We aimed to determine the association between the stepwise increase in the sustained viral response (SVR) and Swiss and United States (US) market prices of drug regimens for treatment-naive, genotype 1 chronic hepatitis C virus (HCV) infection in the last 25 years. We identified the following five steps in the development of HCV treatment regimens: 1) interferon (IFN)-α monotherapy in the early '90s, 2) IFN-α in combination with ribavirin (RBV), 3) pegylated (peg) IFN-α in combination with RBV, 4) the first direct acting antivirals (DAAs) (telaprevir and boceprevir) in combination with pegIFN-α and RBV, and 5) newer DAA-based regimens, such as sofosbuvir (which is or is not combined with ledipasvir) and fixed-dose combination of ritonavir-boosted paritaprevir and ombitasvir in combination with dasabuvir.We performed a linear regression and mean cost analysis to test for an association between SVRs and HCV regimen prices. We conducted a sensitivity analysis using US prices at the time of US drug licensing. We selected randomized clinical trials of drugs approved for use in Switzerland from 1997 to July 2015 including treatment-naïve patients with HCV genotype 1 infection.We identified a statistically significant positive relationship between the proportion of patients achieving SVRs and the costs of HCV regimens in Switzerland (with a bivariate ordinary least square regression yielding an R2 measure of 0.96) and the US (R2 = 0.95). The incremental cost per additional percentage of SVR was 597.14 USD in Switzerland and 1,063.81 USD in the US.The pricing of drugs for HCV regimens follows a value-based model, which has a stable ratio of costs per achieved SVR over 25 years. Health care systems are struggling with the high resource use of these new agents despite their obvious long-term advantages for the overall health of the population. Therefore, the pharmaceutical industry, health care payers and other stakeholders are challenged with finding new drug pricing schemes to treat the entire population infected with HCV. The development and market approval of novel direct-acting antivirals (DAAs) have dramatically changed the hepatitis C virus (HCV) treatment landscape. For the first time, chronic HCV infection, a major human pathogen responsible for cirrhosis and hepatocellular carcinoma and a leading indication for liver transplantation, may be eradicated in all patients using an all-oral, short-duration, well-tolerated, safe, and highly efficacious treatment.A new nosological entity first identified in the 1970s, the so-called non-A, non-B hepatitis, was discovered as HCV in 1989., 3 The fhttp://www.swissmedicinfo.ch) for treatment-naive, genotype 1 chronic hepatitis C patients, corresponding to the most prevalent patient subgroup in our country.[Therefore, a better understanding of the determinants of HCV drug pricing is essential. Key elem country. We also We classified the different treatment regimens into five steps, as suggested by the literature .3, 24, , 24, 25st 1997 to July 31st 2015. For each of these drugs regimens, we used the SVR rate as reported in the studies at the time of the Swissmedic marketing authorization request (http://www.swissmedic.org); Swissmedic is the Swiss agency that authorizes and supervises drugs. The drug price, dosage and duration were based on the recommended Swissmedic guidelines for HCV treatment-naive patients with genotype 1 infection during the study period. For older drug regimens that are not listed in the Swissmedic database, we used data from the corresponding US agency . Finally, because data for IFN-α were not recorded in either database, we contacted the pharmaceutical companies to determine which published studies contributed to drug marketing. [We selected all phase 3 randomized clinical trials (RCT) that enrolled previously untreated patients with chronic HCV genotype 1 infection and tested drugs that were approved by Swissmedic, which were therefore marketed in Switzerland from January 1rketing. ,5 SVR warketing. In Switzerland, market access is conditional on a two-step decision process. First, a drug must be approved by Swissmedic. Then, thfxtop.com/en/inflation-calculator.php). Likewise, for steps 2 and 3, we used the January 2003 prices of IFN-α, pegIFN-α and RBV, which were adjusted by the inflation rate. For the first and second wave DAAs included in steps 4 and 5, we used the launching market price and current price for pegIFN-α and RBV without adjusting for inflation. For the comparison of prices adjusted to the 2015 level, we considered an exchange rate of one CHF equal to one USD. Although RBV administration is usually weight-adapted, we arbitrarily considered a standard daily dose of 1,000 mg for all recipients. We assumed that the US drug costs were equal to the wholesale acquisition costs (WAC) as listed in the Red Book Online (http://www.redbook.com/redbook/online). For regimens requiring RBV, and when many manufacturers shared the RBV market, we selected the cheapest regimen. We also calculated the ratio of costs per SVR (costs/SVR) for each regimen, representing the costs to cure one patient.The market prices of IFN-α, pegIFN-α and RBV have changed throughout the past 25 years. Therefore, we controlled for inflation by using the market price of IFN-α for step 1 in 1997, which was adjusted by the inflation rate for both Swiss and US pricing using an online calculator , two stu patients2 of 0.96 for Switzerland and 0.95 for the US.  The incremental costs per additional percentage point of SVR were estimated as 597.14 USD in Switzerland and 1,063.81 USD in the US by the slope coefficient of the respective regression model  have remained relatively stable over time, at least in Switzerland.For the HCV market, pharmaceutical companies price their drugs based on the value of SVR and profit maximization rather than the costs of R&D, production, marketing and distribution or the volume of drugs used., 34, 35 Drug prices evolved in line with the cure rate from a mere 10% to almost 100% over a 25-year period. Therefore, we could argue that the “very high” nominal prices of the recently introduced HCV DAAs are justifiable. On the other hand, DAAs have other significant advantages, such as improved safety and tolerability, shorter treatment durations, and entirely oral administration. These strong advantages–not present at the time of poorly tolerated IFN-α-based regimens–were not factored into the price of the first DAAs or into the price of the DAAs for the newer wave. Additionally, the purported innovation conferred by the introduction of long-awaited, IFN-free regimens was not responsible for boosting the market price.® , offering a high rebate while subsequently increasing prices if the new drug reduces hospitals visits.[Some antiviral therapies have not only unprecedented high cure rates but are also safe and well tolerated, which makes them theoretically useful for treating nearly the entire infected population, at variance with the IFN-based therapies used in the early 1990s, which were associated with many safety issues and therefore of relatively limited use. Also, ans visits.Our study had limitations. First, we included only treatment-naive patients infected with HCV genotype 1. However, this is the largest subgroup of hepatitis C patients in Switzerland, and it is sufficiently representative for studying the pricing business model. MoreoverIn conclusion, there is a relatively stable ratio of costs per cured patient over time, resulting in a strong positive correlation between the HCV cure rate and costs per treatment. This is an indication that pharmaceutical companies used a value-based pricing model for HCV treatments. The finding is in line with a claim by Ezekiel J. Emanuel, who stated that high HCV prices are not fully accounted by high costs of R&D or risks associated with drug development.  Health cS1 FileTable A in S1 File: Data set: SVR, Swiss costs (USD), United States (US) costs (USD), cost per SVR in Switzerland (USD), costs per SVR in US (USD), stepping stones dummy variables. Table B in S1 File: The Swiss incremental costs per additional percentage point of SVR regression coefficients. Table C in S1 File: The Swiss incremental costs per additional percentage point of SVR regression table output. Table D in S1 File: The US incremental costs per additional percentage point of SVR regression coefficients. Table E in S1 File: The US incremental costs per additional percentage point of SVR table output. Table F in S1 File: Mean SVR, 95% CI output. Table G in S1 File: Mean costs and 95% CI in Switzerland output. Table H in S1 File: Mean costs per SVR and 95% CI in Switzerland output. Table I in S1 File: Mean costs and 95% CI in the US output. Table J in S1 File: Mean costs per SVR and 95% CI in the US output.(DOCX)Click here for additional data file.


Research on morbillivirus infections has led to exciting developments in recent years. Global measles vaccination coverage has increased, resulting in a significant reduction in measles mortality. In 2011 rinderpest virus was declared globally eradicated – only the second virus to be eradicated by targeted vaccination. Identification of new cellular receptors and implementation of recombinant viruses expressing fluorescent proteins in a range of model systems have provided fundamental new insights into the pathogenesis of morbilliviruses, and their interactions with the host immune system. Nevertheless, both new and well-studied morbilliviruses are associated with significant disease in wildlife and domestic animals. This illustrates the need for robust surveillance and a strategic focus on barriers that restrict cross-species transmission. Recent and ongoing measles outbreaks also demonstrate that maintenance of high vaccination coverage for these highly infectious agents is critical. This introduction briefly summarizes the most important current research topics in this field. Morbillivirus belongs to the virus family Paramyxoviridae, a group of enveloped viruses with non-segmented, negative strand RNA genomes. It contains viruses that are highly infectious, spread via the respiratory route, cause profound immune suppression, and have a propensity to cause large outbreaks associated with high morbidity and mortality in previously unexposed populations. In populations with endemic virus circulation, the epidemiology changes to that of a childhood disease, as hosts that survive the infection normally develop lifelong immunity. The genus Morbillivirus include peste des petits ruminants virus (PPRV), which causes disease in small ruminants, such as goats and sheep; canine distemper virus (CDV), which causes distemper in dogs and a large number of other carnivore species; phocine distemper virus (PDV), which leads to distemper in several seal species and cetacean morbilliviruses (CeMV), which cause disease in dolphins and whales. As shown in Morbillivirus [Measles virus (MV) is the prototype morbillivirus, and causes disease in primates. Rinderpest virus (RPV) is closely related to MV and used to cause severe disease in cattle. Other viruses in the genus llivirus . Yet agaMeasles remains a significant cause of childhood morbidity and mortality in humans. The disease is characterized by fever, skin rash, cough and conjunctivitis, and a generalized immune suppression . The resMorbillivirus genus, MV is most closely related to RPV. It has been postulated that RPV or a closely related ancestral cattle virus crossed the species barrier into humans 1000–5000 years ago [Within the ears ago . At the ears ago ,10. In cears ago .Viruses [PPRV is referred to as “the plague of small ruminants” and is a highly contagious and fatal disease for sheep and goats. Being closely related to RPV, and considering the importance of sheep and goats to farmers in Africa and South Asia, PPRV may also become a potential candidate for global eradication . A comprViruses .Canine distemper has been described as an infectious disease of dogs since the 17th century, but CDV has the capacity to infect a wide range of carnivores. Since distemper is associated with high morbidity and mortality , most doPDV and CeMV, two phylogenetically distinct morbilliviruses, have caused significant disease outbreaks in marine mammals. PDV mainly infects seals, and two large outbreaks have been reported thus far. In 1988, approximately 18,000 harbor seals died in northwest Europe. A second, and equally devastating outbreak, occurred in the same area in 2002 . NotablyOver the last three decades CeMV has been responsible for large disease outbreaks among cetaceans, including harbor porpoises, striped dolphins, bottlenose dolphins, and pilot whales. Two comprehensive reviews of morbillivirus infections in seals and cetaceans can be found in this issue ,21.Recently, novel morbilliviruses were detected in felines and bats. FmoPV was first described in 2012 as a morbillivirus of cats, and has thus far only been identified in China and Japan. Phylogenetically FmoPV is distantly related to the other morbilliviruses . In addiInfection of cells by morbilliviruses is initiated by binding of the hemagglutinin (H) glycoprotein to cellular receptors. Two cellular receptors have been described for wild-type morbilliviruses: CD150  in 2000  and poliInterestingly, the phylogenetic relationships of the morbilliviruses largely parallel those of their respective host species ,26. The Of all the morbilliviruses CDV is the most promiscuous, infecting many different carnivore species. Even though initially less pathogenic in new carnivore hosts, the virus caused large disease outbreaks in phocids and felids . CDV alsVaccination is the most effective intervention strategy to combat morbillivirus infections. Morbilliviruses are even considered as vectors for protection against other infectious diseases . In receIn recent years, MV has extensively been tested as a potential oncolytic virus . These tThe identification of cellular receptors and improvement of animal models has provided important new insights into the pathogenesis of morbillivirus infections. It has become clear that all morbilliviruses initially infect cells of the immune system, before they spread to epithelial, endothelial and/or neuronal cells. Morbilliviruses remain a potential cause of disease outbreaks in previously unexposed populations. However, they can also be used to our advantage, as vaccine vectors or as oncolytic viruses. Sustained vaccination coverage and surveillance of circulating morbilliviruses will remain of critical importance for years to come .


CCR5 gene encodes a cytokine receptor important for cell-mediated immune response against H1N1pdm09. A 32-bp polymorphic deletion in the coding sequence of CCR5, the so-called CCR5Δ32 allele, segregates in populations of European ancestry with a frequency of 8-15%. A high proportion of CCR5Δ32 heterozygotes was reported in a sample of white Canadian critically-ill H1N1pdm09 infected subjects, suggesting an association with disease severity.Host genetic factors are thought to modulated the severity of disease caused by infection with the 2009 H1N1 pandemic influenza virus (H1N1pdm09). The human We recruited 29 H1N1pdm09 infected subjects from Southern Europe  with a wide clinical spectrum of disease symptoms; the sample included 7 subjects who developed acute respiratory distress syndrome requiring extracorporeal membrane oxygenation. The CCR5Δ32 variant was genotyped in all subjects.The CCR5Δ32 allele was found in one single subject, who developed a very mild form and was not hospitalized.The CCR5Δ32 allele was not found to be associated with the risk of H1N1pdm09 infection or with a severe disease course. The swine-origin H1N1 influenza A virus that appeared in Mexico in 2009 (H1N1pdm09) caused the first flu pandemic of the 21st century. H1N1pdm09 infection resulted in a substantial diseases burden with a minority of infected subjects developing life-threatening respiratory complications. Estimates of H1N1pdm09-associated mortality are similar in magnitude to that of seasonal influenza, but most deaths occurred in healthy people younger than 65 years old [Indeed, studies based on historical registries indicated that genetic factors affect the risk of death due to influenza virus infection . LikewisClearly, the identification of host genetic factors that modulate the susceptibility to and the severity of influenza virus infection is of paramount importance to develop preventive strategies and therapeutic interventions.IFITM3 gene (rs12252), was originally described in a cohort of 53 influenza UK cases who developed severe respiratory complications [CCR5 gene, the so-called CCR5Δ32 allele, which is almost exclusive to individuals with European ancestry. In a Canadian sample of 9 Caucasian patients with severe H1N1pdm09 infection Keynan et al. [Ccr5−/− mice have indicated that, when infected with influenza A virus, these animals display accelerated macrophage accumulation in the lungs and increased mortality compared to wild-type mice [Recently, a case–control study of 91 Mexican patients with confirmed severe pneumonia from H1N1pdm09 infection identified three independent association signals . Neverthications . The assications . Nonethen et al. . Also, sype mice .Herein we investigated whether the CCR5Δ32 associates with disease severity in H1N1pdm09 infected southern European patients.We analyzed 29 subjects with laboratory confirmed H1N1 infection who were referred to the Infectious Disease Unit of the San Gerardo Hospital, Monza, Italy, in winter 2009–2010. Most patients described herein were recruited immediately after the H1N1 outbreak in a relatively short time period. Peripheral blood samples were obtained from H1N1pdm09 infected patients as part of their care pathway. All patients signed an informed consent allowing leftover blood samples to be used for research purposes. The informed consent form was approved by the Internal Review Board of the San Gerardo Hospital and explicitly mentioned the use of leftover samples for genetic research. Samples were stored and processed anonymously. The authors have presently no access to identifying information and cannot relate genetic data to individual subjects. The study was conducted in accordance with the ethical standards of the Helsinki Declaration. All subjects were of European ancestry  with the exception of a Chinese patient (in the mild form group). The clinical characteristics of these subjects are summarized in Table For all subjects genomic DNA was obtained from peripheral blood mononuclear cells. The CCR5Δ32 variant was genotyped by PCR amplification using a forward primer (CCR5-D32-F: TTTACCAGATCTCAAAAAGAAG) and a fluorescently labelled reverse primer . PCR-amplified fluorescently tagged samples were run on 3500xL Genetic Analyzer (Life Technologies) using the GeneScanTM 600 LIZ® size standard (Life Technologies). The PCR amplicons were separated by size electrophoresis and the dye labeled products were identified by fluorescence detection. GeneMapper® Software Version 4.0 was applied to size the alleles Figure .CCR5 gene was genotyped.We recruited 29 subjects with laboratory confirmed H1N1 infection. Twenty-one of these patients were hospitalized; seven of them developed acute respiratory distress syndrome (ARDS) and required extracorporeal membrane oxygenation (ECMO). These subjects are referred to as having a severe flu form  , resultiIFITM3 previously associated with H1N1pdm09 disease severity shows strong frequency variation depending on ancestry. Its frequency is very low in Europe (but much higher in Asia) and a recent analysis of 34 severe H1N1pdm09 patients from the UK detected no association (whereas an effect of the rare homozygous genotype was detected for mild influenza) [We evaluate the possible association between the CCR5Δ32 allele and severe H1N1pdm09 infection in patients form Southern Europe. CCR5 has been shown to be important for cell-mediated immune response against H1N1pdm09 ,14 and tfluenza) .Overall, results from these previous analyses together with those reported herein indicate that larger sample sizes will be required to perform robust association studies for H1N1pdm09 disease severity. Thus, provided that host genetics play a role in the susceptibility to this condition, most of its determinants in European ancestry subjects remain to be identified.ARDS: Acute respiratory distress syndrome; ECMO: Extracorporeal membrane oxygenation.The authors declare that they have no competing interests.MS, MC, and AG conceived and designed the study; RC and CP performed molecular genetic analyses; GM and MR recruited patients and provided clinical data; MS, MC, and AG wrote the manuscript. All authors read and approved the final manuscript.


After a 16-year interval, foot-and-mouth disease virus serotype SAT 3 was isolated in 2013 from an apparently healthy long-horned Ankole calf that grazed close to buffalo in Uganda. The emergent virus strain is ≈20% different in nucleotide sequence  from its closest relatives isolated previously from buffalo in Uganda. Picornaviridae family) (http://www.wrlfmd.org/fmd_genotyping/2013.htm).Foot-and-mouth disease (FMD) remains one of the most economically important diseases of livestock, costing ≈US $10 billion annually  (Syncerus caffer), and domestic animals, 20 long-horned Ankole cattle (≈6 months of age) were introduced as sentinel animals into Nyakatonzi (Kasese District), in close proximity to the QENP. At the time they were transported, these animals, originating from another area where FMD outbreaks had not been reported for ≈10 years, had no circulating antibodies against FMDV nonstructural proteins (NSPs) . Blood and probang samples  were obtained from individual animals at 2-week intervals after their entry to the farm from which they moved regularly into the QENP for pasture and water. These sentinel animals freely mixed and grazed with buffalo (observed within a few meters of each other) and other local cattle. More than 6,000 buffalo are present within the QENP.In 2013, as part of a study of FMDV transmission between wildlife, especially African buffalo ; RNA was extracted from the probang samples and analyzed for FMDV genomes by using pan-serotypic real-time reverse transcription PCR (RT-qPCR) , and we An aliquot of the probang sample from calf no. 34 was inoculated onto primary bovine thyroid cells for virus isolation. We observed cytopathic effects within 48 hours and assayed the virus harvest using serotype-specific antigen ELISAs. We observed a strong signal , indicating SAT 3 FMDV with no significant signal for other serotypes (data not shown). The presence of FMDV RNA in the cell harvest was demonstrated by using RT-qPCR (cycle threshold 11), indicating isolation and growth of FMDV; the isolate was named SAT 3 UGA/1/13. To characterize this strain, we amplified the RNA region encoding viral protein (VP) 1 by RT-PCR; the amplicon (821 bp) was sequenced with a BigDye Terminator v. 3.1 Cycle Sequencing Kit and an ABI PRISM 3730–DNA Analyzer .http://blast.st-va.ncbi.nlm.nih.gov/Blast.cgi) in MEGA5  was obtained from an apparently healthy long-horned Ankole calf that was newly introduced into the QENP. To our knowledge, this is the first isolation of SAT 3 FMDV from cattle in East Africa. The VP1 coding sequence was ≈20% different from the most closely related virus strains within Uganda and up to 36% divergent from SAT 3 viruses from southern Africa. The Ugandan SAT 3 viruses should be classified within a single topotype (V), but this requires modification of the topotype definition used previously (


Reliable estimates of the impacts of chronic kidney disease (CKD) stage, with and without cardiovascular disease, on hospital costs are needed to inform health policy.The Study of Heart and Renal Protection (SHARP) randomized trial prospectively collected information on kidney disease progression, serious adverse events and hospital care use in a cohort of patients with moderate-to-severe CKD. In a secondary analysis of SHARP data, the impact of participants’ CKD stage, non-fatal cardiovascular events and deaths on annual hospital costs  were estimated using linear regression.7,246 SHARP patients  from Europe, North America, and Australasia contributed 28,261 years of data. CKD patients without diabetes or vascular disease incurred annual hospital care costs ranging from £403  in CKD stages 1-3B to £525 (449-602) in CKD stage 5 . Patients in receipt of maintenance dialysis incurred annual hospital costs of £18,986  in the year of initiation and £23,326  annually thereafter. Patients with a functioning kidney transplant incurred £24,602  in hospital care costs in the year of transplantation and £1,148  annually thereafter. Non-fatal major vascular events increased annual costs in the year of the event by £6,133  for patients on dialysis and by £4,350  for patients not on dialysis, and were associated with increased costs, though to a lesser extent, in subsequent years.Renal replacement therapy and major vascular events are the main contributors to the high hospital care costs in moderate-to-severe CKD. These estimates of hospital costs can be used to inform health policy in moderate-to-severe CKD.The online version of this article (doi:10.1186/s12882-015-0054-0) contains supplementary material, which is available to authorized users. In the United Kingdom (UK), the age-standardized prevalence of chronic kidney disease (CKD) stages 3 to 5 not on renal replacement therapy (RRT) has been estimated at 11% for females and 6% for males . The annThe estimate of NHS expenditure on CKD in England in Kerr et al.  was deriDetails of the design of the SHARP trial and its main results have been reported previously ,16. BrieFollowing randomization, patients were followed up at study clinics at 2 and 6 months, and then every 6 months. At each follow-up visit, information on all hospital admissions and possible study outcomes was recorded. If a patient became unwilling or unable to attend follow-up visits, information was sought from them (or a relative or carer) by telephone or from their doctor until the scheduled study end. Further information was sought from hospital records and other appropriate sources for all events that might represent an important study outcome. Trained clinicians adjudicated important study outcomes in accordance with pre-specified definitions. All diagnoses were subsequently coded into the International Classification of Diseases (ICD-10) system and all procedures into the Operating Code Supplement (OPCS-4.5) system. For the purpose of the hospital cost analysis, follow-up time was divided into annual periods from the date of randomization to the end of study. Only fully observed annual periods and annual periods shorter than one year due to death were included in the cost analysis.Cardiovascular disease and vital status were determined for each patient at the end of each annual period and categorized into a mutually exclusive hierarchy (in descending order): i) vascular death during the current annual period; ii) non-vascular death during the current annual period; iii) a non-fatal major vascular event  during the current annual period; iv) most recent non-fatal MVE in the preceding annual period; v) most recent non-fatal MVE occurred in the annual period before last; vi) most recent non-fatal MVE occurred more than two annual periods previously; vii) prior vascular disease at randomization but no MVE since; and, viii) no vascular disease at randomization and no subsequent MVE.2); CKD stage 4 ; CKD stage 5 not on RRT (eGFR <15 ml/min/1.73 m2); maintenance dialysis initiated in the current annual period; maintenance dialysis initiated in a preceding annual period; kidney transplantation in the current annual period; or, functional kidney transplant from an earlier annual period. In the cases in which information was absent, the latest information on CKD stage was carried forward for up to two years .Renal status was determined at each follow-up visit using local measurements of serum/plasma creatinine, or, where relevant, current RRT modality. For each annual period, the mean of all recorded creatinine results in the period was used to calculate the CKD Epidemiology Collaboration (CKD-EPI) estimated glomerular filtration rate (eGFR)  and cateAll serious adverse events related to hospital care use were classified into one of four mutually exclusive categories: i) atherosclerotic events; ii) non-atherosclerotic vascular events; iii) renal events; or iv) other events  ) and greatest in those with CKD stage 5 not on RRT (0.59 ppy). Hospital episodes for both atherosclerotic and non-atherosclerotic vascular disease per patient-year more than doubled from 0.02-0.03 ppy among those in CKD stages 1-3B to 0.08 ppy in those on dialysis at baseline  annual periods, ranging from 24% of annual periods among those in CKD stages 1-3B at baseline to 91% of annual periods in those on maintenance dialysis at baseline  in CKD stages 1-3B to £525 (449-602) in CKD stage 5. This was mainly due to 19% of annual periods in CKD stage 5 containing admissions for the formation/insertion of dialysis access, compared to 2% in CKD stage 4. CKD patients in receipt of maintenance dialysis incurred £18,986  costs in the year of initiation and £23,326  in each subsequent year. Average annual hospital care costs in the year of transplantation were £24,602 , largely due to the costs of admission for the transplant operation itself  and £1,391  respectively. Non-fatal MVEs increased annual hospital care costs in the year of the event by £4,350  for individuals not on dialysis (including those with a functioning transplant) and by £6,133  for those receiving dialysis. The effect of a vascular event on hospital costs remained, but was diminished, in subsequent years: in the absence of further MVEs, the effect of a non-fatal MVE on hospital costs in the following year was £738  and £172 (57-286) in each year thereafter. Having prior diabetes at entry into the study was associated with additional annual hospital costs of £171 (54-288) , but also costs of other related health problems in the year. Consequently, the average estimated additional cost of a major vascular event in the annual period in which it occurred  are substantially higher than the separate reference costs of vascular events . MoreovRenal replacement therapy has a substantially greater impact on annual hospital costs than vascular events. Although the annual hospital care cost in the year of kidney transplantation was about 10% greater than the cost in a year of initiating dialysis, in subsequent years, kidney transplantation was associated with substantially lower hospital care costs compared to maintenance dialysis.2) and CKD stage 4 in SHARP. Patients with CKD stage 5 not on RRT were estimated to incur a small additional cost relative to earlier CKD stages, mainly attributable to access procedures performed in preparation for dialysis. There are a number of analytical differences between the SHARP cost study and previous studies that might explain this. First, unlike previous studies in which resource use and costs were summarized according to each patient’s baseline CKD stage, irrespective of further CKD progression, in SHARP costs were attributed to the actual stage of CKD at the end of each annual period. Second, in SHARP, the hospital costs of cardiovascular complications and deaths were evaluated separately from other hospital care. Third, this SHARP cost analysis focused on hospital care costs , but unlike in previous studies, other healthcare costs relevant to a CKD population (and increasing with kidney disease severity) such as costs for routine outpatient appointments, transport to and from hemodialysis units, primary care and prescription drugs [In contrast to previous studies which reported increasing trends in healthcare costs by CKD stage ,12, theron drugs ,12-14 weSHARP recruited patients aged 40 years and older with moderate-to-severe CKD (mostly at stages 3B or worse) without a prior myocardial infarction or coronary revascularization. Consequently, SHARP is not representative of the full CKD population where CKD stage 1-3A predominates and the prevalence of coronary (and other comorbidities) is greater and increases with kidney disease severity . As a coA further potential limitation is that data on hospital resource use from the UK and other countries was used to inform UK costs. Preliminary work found no heterogeneity in hospital episode rates between countries conditional on events, except for patients recruited in Asia, who were excluded. The cost model using only UK patients produced similar results but was of limited power . The UK hospital care costs in CKD, presented here, are likely also to be of limited generalizability to other countries contributing patient data for the analysis, as the respective costs of hospital services in these countries might differ from those in the UK.http://www.herc.ox.ac.uk/downloads/supportingmaterial.The UK annual hospital care costs model in moderate-to-severe CKD presented here identifies renal replacement therapy, major vascular events and deaths (vascular and non-vascular) as the key determinants of costs. The model allows reliable evaluation of effects of interventions and policies to modify rates of vascular events, progression of CKD, kidney transplant survival or access to transplantation in this population on hospital costs. To assist such efforts, a downloadable cost calculator is available at Additional file 1:Supplementary material to “What is the impact of chronic kidney disease stage and cardiovascular disease on the annual cost of hospital care kidney in moderate-to-severe disease?”.


It is well known that search costs and switching costs can create market power by constraining the ability of consumers to change suppliers. While previous research has examined each cost in isolation, this paper demonstrates the benefits of examining the two types of friction in unison. The paper shows how subtle distinctions between the two costs can provide important differences in their effects upon consumer behaviour, competition and welfare. In addition, the paper also illustrates a simple empirical methodology for estimating separate measures of both costs, while demonstrating a potential bias that can arise if only one cost is considered. ► We show the benefits of studying search costs and switching costs in unison. ► The two costs have different effects on competition and welfare. ► In most cases, search costs are the more anti-competitive and welfare damaging. ► We also offer a methodology to estimate separate measures of the two costs. For example, in order to change suppliers in a market for a financial product or utility, consumers may have to first spend time searching for information about an alternative, before then incurring switching costs by completing the necessary paperwork. Indeed, the importance of considering both forms of friction within the same market is highlighted by a number of competition policy investigations, not least in the banking sector, where the UK and EU authorities remain concerned over both the transparency of price information and difficulties within the switching process , our methodology emphasises the potential importance of accounting for both frictions. Indeed, by attributing any market imperfection to only one cost, we demonstrate how some ‘single-cost’ measures can exhibit an upward bias.c per firm, consumers can search firms sequentially in order to learn each firm's price and their willingness to pay for each firm's product. After having stopped searching, each consumer must then decide whether to remain with their existing supplier or to trade with a previously searched alternative firm for an extra switching cost, s. We present the equilibrium of a game where firms select prices and consumers simultaneously select their search and switching strategies. The equilibrium generalises the results of some standard models that consider only one cost, such as The theoretical model is presented in In Finally, 2Two previous papers have offered a theoretical analysis of search costs and switching costs. both search costs and switching costs.The empirical literature has received somewhat more previous attention. In addition to some studies that use reduced form analysis to analyse both costs,In the previous literature, only 3While previous papers appear to agree on the differences between search costs and switching costs, this section attempts to offer a more formal distinction between the two costs. Search costs are the costs incurred by a consumer in identifying a firm's product and price, regardless of whether the consumer then buys the product from the searched firm or not.Switching costs are the costs incurred by a consumer in changing suppliers that do not act to improve the consumer's pre-purchase information.Finally, while it is possible that firms may be able influence the level of search costs and switching costs in practice, our later model will follow the tradition within the literatures by treating the two costs as exogenous. Like other standard models, this implies that the costs of switching are best interpreted as exogenous forms of real social costs rather than as contractual costs . For exa4m gain an indirect utility (excluding any search or switching costs) of i at price Let there be m is local to firm i, she can learn her match value and the price at firm i, i. However, in order to switch to any non-local firm j and firm j's price, j. Search is assumed to be sequential with costless recall. Hence, consumer m is able to search any number of non-local firms one by one, incurring a cost of c each time, before choosing whether to purchase from her local firm i or, for an extra cost of s, from a searched non-local firm The market is assumed to be mature in the sense that each consumer is already partially locked-in to their ‘local’ firm. Each consumer is free to search and trade with their local firm but faces costs of searching and switching in regard to any other ‘non-local’ firm. In line with standard search models e.g. , the maim should start searching beyond her local firm (Step 1), when to stop searching amongst non-local firms (Step 2) and which firm to then trade with (Step 3).A one-shot static game is considered where the players select the following strategies simultaneously. Firms each select a single price, 55.1This section begins the equilibrium analysis by considering the optimal search to switch strategy for a given consumer. For simplicity, we will assume that the consumer correctly conjectures that all her non-local firms set a price equal to the symmetric equilibrium price, Definition 1x that solves The reservation utility, To ease the exposition, it is first worth recalling a well-known feature of the optimal strategy in the standard case without switching costs. In particular, suppose a consumer has previously searched a number of non-local firms and that her highest discovered non-local offer, c, a new offer of The derivation of this stopping rule is surprisingly simple. First, suppose that the number of remaining unsearched non-local firms, Lemma 1Given a search cost, c, and switching cost, s, the optimal search to switch strategy consists of the following.Step1: Refrain from searching any non-local firm iforOtherwise search any unsearched non-local firm.Step2: Stop searching amongst the non-local firms only if some firm j is found such thator if all firms have been searched.Step3: Having stopped searching, trade with the searched firm offering the best deal, iffOtherwise take the zero outside option.The derivation of Steps 1 and 2 is now discussed in detail. However, a consideration of their implications and the roles played by Distinctions 1–4 is best left until we cover the comparative statics of the full model in s, then drops out and the expression reduces to the same reservation utility, First, consider Step 2. Having started a non-local search, c in order to discover a single offer, denoted by Let us now move back to the original decision of whether to initiate a non-local search in Step 1. In contrast to Step 2, switching costs now become important because the consumer must compare between (i) collecting the existing local offer (or outside option) which excludes switching costs, 5.2This section considers the firms' optimal pricing decisions. As adopted in other recent search models e.g. , attentiCondition 1In equilibrium, From i. Given a price of i and a price of i, Under this condition, one can establish the equilibrium price by first deriving the residual demand for firm i's local fresh demand, i's i if Firm i's non-local fresh demand, i but choose to visit firm i during their search process and find it optimal to stop and buy. The total number of visits to firm i made by non-local consumers can be expressed as i conditional on visiting, equals i it will then be optimal to buy from firm i:Firm i's return demand consists of consumers who start searching but never find an offer worth stopping for. They end up searching the entire market before then realising that firm i offered the best deal and returning to buy from firm i. Depending upon whether such consumers are local or non-local to firm i, this demand is denoted as local return demand, In contrast to these two components of fresh demand, firm Proposition 1When a symmetric equilibrium exists, the equilibrium price is unique and is characterised bywhereiffand zero otherwise:Given the residual demand function presented in In the first case, when In the second case, where Finally, before examining the comparative statics in detail, it is worth considering some special cases. First, if one sets switching costs to zero, the price derived in 6In this section, we examine the relative mechanisms by which changes in the level of search costs and switching costs affect the equilibrium price and welfare. 6.1Proposition 2The equilibrium price under non-market coverage, is increasing in the level of search costs, c, for alland increasing in the level of switching costs, s, for alland forifThe case of non-market coverage is easiest to analyse. As a preliminary step, Proposition 3Under non-market coverage, the marginal effect from an increase in search costs on the equilibrium price is always larger than the marginal effect from an increase in switching costs.Of more interest are the different underlying mechanisms that generate such price effects. To gain an understanding of s. This follows from the assumption that only search costs can be incurred across multiple suppliers (Distinction 4).The first expression relates to the effect of search costs on increasing the equilibrium price by reducing the extensiveness of consumers' non-local search activity. Holding constant the fraction of consumers who start searching, The second expression concerns the net impact of search costs relative to switching costs on increasing the equilibrium price by deterring consumers from initiating any non-local search activity. Holding constant the extensiveness of any search, Finally, the last expression relates to the effect of an increase in switching costs on consumers that have searched the entire market. An increase in switching costs makes such fully informed consumers less likely to switch to a non-local firm and here, under non-market coverage, more likely to leave the market without making a purchase. This reduces each firm's demand, As a simplified summary, we can see that the relative power of search costs largely derives from the following. A consumer who searches beyond her local firm (i) must incur a search cost and yet may not choose to later incur a switching cost (via Distinctions 2 and 3) and (ii) may choose to incur multiple search costs (via Distinction 4). Many remaining results in the paper will build on this foundation intuition.6.2Proposition 4The equilibrium price under market coverage, is increasing in both the level of search costs, c, and the level of switching costs, s, for allWe now move on to the setting of market coverage. The mechanisms by which search and switching costs affect the equilibrium price are very similar to those under non-market coverage. Consequently, it can be shown again that the equilibrium price is increasing in each friction. increase their price. This change in mechanism makes any difference in magnitude between the marginal effects of search costs and switching costs less stark. However, n, is sufficiently large. Proposition 5Under market coverage, the marginal effect of search costs on the equilibrium price is always larger than the marginal effect of switching costs when the number of firms is greater than or equal to four.However, there is one difference in the mechanism regarding the effect of switching costs on deterring fully informed consumers from trading with non-local firms. Under non-market coverage, this made such consumers more likely to exit the market and gave firms an incentive to decrease their price. Now, under market coverage, this makes such consumers more inclined to purchase from their local firm and gives firms an incentive to When there are two or three firms, either cost can have the larger marginal effect. However, when the number of firms is larger, search costs have the consistently bigger impact on market power. Intuitively, this follows from two effects. First, as the number of options grows, consumers that have searched the entire market become more price sensitive and are less affected by the loyalty-inducing effects of switching costs. Second, an increase in the number of firms tilts the relative composition of each firms' demand towards non-local consumers and enhances the effects of search costs on deterring the initiation and extensiveness of any search activity.6.3Proposition 6If the marginal effect from an increase in search costs on price is larger than the marginal effect from an increase in switching costs, then, relative to a unit increase in switching costs, a unit increase in search costs generates a greater reduction in aggregate consumer surplus, CS, a greater decrease in total welfare, W, and a greater increase in industry profits, In most cases, search costs appear to be the relatively more powerful determinant of market power. To be able to provide better policy advice, this subsection considers their relative effects on welfare. We now state directly in two ways. It will (i) increase the price paid by existing buyers and (ii) increase the cost of switching to existing switchers. If one denotes the number of existing switchers as indirectly by changing consumers' behaviour. In particular, while an increase in switching costs will have no effect on the extensiveness of consumers' search activity, it will (iii) decrease the number of consumers who choose to search beyond their local firm, via a reduction in the local reservation utility, The effects on aggregate consumer surplus are more complex. Consider a marginal increase in switching costs. This will affect consumer surplus With the application of an envelope-style argument, related to that used in A similar argument can be used in respect to an increase in search costs. By denoting This implies that Finally, one can use similar arguments to show that search costs also provide the relatively larger marginal effect on total welfare. As the loss in consumer surplus from an increased price for existing buyers is appropriated by firms in industry profits, the only (first-order) effects on total welfare stem from the increased cost of existing search and switching activity, such that To summarise, 7This section now investigates the robustness of the results by presenting a variety of extensions. Most importantly, we first consider the introduction of dynamic effects. We then investigate the possibility of costly local search, asymmetric consumer locations, price discrimination and switching without searching.7.1In order to provide a clear analysis of the subtle differences between the two frictions, the model has deliberately neglected any consideration of dynamic competition. However, we expect that it would only strengthen the findings. To illustrate, consider a two-period version of the model where each consumer enters the market in period 1 with no switching costs, makes an initial purchase at some firm and then finds it costly to switch away from that firm in period 2. In effect, our model has only analysed period 2, where firms have an incentive to exploit or ‘harvest’ their locked-in  consumers. Now consider period 1. If the firms are myopic and do not consider the impact of their period 1 decisions on their period 2 profits, then it is clear that the comparative statics would remain consistent with our original model. If, instead, the firms are forward-looking, then the comparative statics are likely to be strengthened. To understand why, note that the introduction of dynamic competition often erodes the anti-competitiveness of switching costs by prompting firms to lower their initial (period 1) prices in order to ‘invest’ in market share and earn higher future ‘lock-in’ profits (in period 2) . However7.2x that solves this expression, It was originally assumed that consumers could search their local firms without cost. We will no show that the introduction of costly local search makes no difference to the pricing equilibrium and actually strengthens the comparative static results on welfare. If a local search now costs the same as a non-local search, 7.3same firm. For example, after a monopoly market has been liberalised all consumers may face costs of search and switching away from the incumbent. To show how our results are robust in such a setting, consider an equilibrium where the incumbent, say Firm 1, sets a price, n is large. Proposition 7Consider the incumbent model withandThen, relative to a unit increase in switching costs, a unit increase in search costs generates a larger increase in equilibrium prices and industry profits, and a greater reduction in consumer surplus and total welfare.As in standard search models, the basic model assumed that each firm was endowed with a symmetric share of local consumers. However, in practice, it may be the case that all consumers are local to the n is large, any consumer who searches beyond the incumbent will always find an attractive non-local offer and never return to the incumbent. This makes Distinction 1 inactive. Now consider the incumbent's choice of price. Its demand derives solely from consumers that wish to buy without starting a non-local search. From previous results, we know that an increase in search costs provides the relatively stronger effect in deterring consumers from starting such a search via Distinctions 2 and 3. Consequently, an increase in search costs will provide the relatively stronger effect in raising the incumbent's price. To consider the entrants' price, note that each entrant's demand derives solely from consumers that started to search beyond the incumbent and decided to stop after visiting the entrant. A rise in search costs deters consumers from pursuing further non-local searches and allows each entrant to increase its price. However, a rise in switching costs has no such effect on the incentives to further search via Distinction 4 and so leaves entrants' prices unchanged. Finally, having confirmed the relative effects on prices, the relative effects on welfare can also be established using similar arguments to those used in To understand why the incumbent's price and the entrants' prices are more sensitive to search costs rather than switching costs, note that when 7.4i can set a price, n is large. Within this setting, it is also possible to allow a very general configuration of consumer locations, where firm i has a proportion of local consumers equal to Proposition 8Consider the price discrimination model withandThen, relative to a unit increase in switching costs, a unit increase in search costs generates a larger increase in equilibrium prices and industry profits, and a greater reduction in consumer surplus and total welfare.Contrary to the original model, it is sometimes possible for firms to discriminate between their local and non-local consumers. We will now demonstrate that our results remain robust when any firm n is large, there is no return demand and so each firm's local demand derives only from consumers that wish to purchase without starting a non-local search. Via Distinctions 2 and 3, a rise in search costs deters consumers from starting to make a non-local search and raises the optimal local price by an amount greater than that generated by a rise in switching costs. Second, consider non-local prices. Each firm's non-local demand derives from consumers that have started a non-local search and then decided to stop. A rise in search costs deters consumers from pursuing further non-local searches and raises the equilibrium non-local price, but an increase in switching costs has no such effect via Distinction 4. Finally, the results on welfare again follow easily using similar arguments to those used in The intuition for this result is surprisingly similar to that in 7.5Finally, in the vast majority of industries, it is clear that consumers will necessarily have to incur positive costs in gathering and processing some information before switching suppliers. However, in some cases it may be possible for a consumer to bypass any such activity by blindly switching to an alternative firm without first knowing its price or characteristics. For example, this possibility is discussed in 8both search costs and switching costs. While the model's underlying assumptions are clearly restrictive in a real-world context, the resulting empirical methodology is extremely simple and requires only minimal data. It is hoped that further work may expand the current methodology to improve its generality and enable it to become a practical measurement tool for competition authorities in the future. After presenting the methodology in As a secondary contribution, this final section considers a data application. In the spirit of 8.1a, should be described by the following equation:The methodology is able to generate separate estimates for the two costs, b, should be described by the following equation:Second, provided there are more than two firms, the model suggests that consumers will switch after making exactly one non-local search if they receive a local match value lower than b can be divided by a to suggest that the fraction of searching consumers who are observed to switch after only one search, One can now use Having constructed the measure of search costs for a given a and b. However, the interpretation of the measures will remain limited because the maximum gains from search, To calculate numerical values for the two measures for an actual market, one can then use aggregate survey data about the levels of a, the implied condition, Finally, it is useful to highlight the importance of accounting for both forms of friction separately within the methodology. To illustrate, suppose a researcher falsely believes that search costs are negligible. The condition in 8.2a and b. The survey values and the resulting measures are presented in the first five columns of a and b should be measured is three years. In some markets, such as the market for mortgages, this may be appropriate.As an example, the proposed measures are now calculated for eight different markets from the UK using responses from a survey of 2027 consumers.a, which suggests switching costs are high.Several observations can be made. First, the results suggest that the ratio of switching costs to search costs in the benchmark case, a, is lower under the annual assumption and the model explains this by raising the estimated level of switching costs.Second, the relative size of switching costs is estimated to be even larger under the assumption of an annual decision period, As detailed below, these initial estimates are open to many limitations. However, the finding that switching costs may be so large relative to search costs does raise the possibility that authorities may prefer to lower switching costs rather than search costs. While our previous theoretical results suggested that the marginal benefits from a reduction in search costs are often larger than those from a reduction in switching costs for any levels of the two costs, the overall net welfare effects could be reversed if switching costs are sufficiently easier to reduce. Authorities should bear this point in mind when making their policy decisions.Finally, one can confirm the potential upward bias of the single-cost measures, 8.3The finding that switching costs are larger than search costs does not seem inconsistent with the existing literature.i such that s, from the preference parameter, Some major limitations arise from the assumptions regarding consumers' product valuations. First, the methodology relies heavily on the unrealistic assumption that the product valuations are drawn from a uniform distribution. More substantially, the methodology is also limited by the assumption that the product valuations are independently drawn from an identical distribution. This implies that any excessive reluctance by consumers to search or switch away from a supplier is automatically attributed to the existence of market frictions. However, in practice, such inertia could also be explained by heterogeneous consumer preferences and yet, the methodology offers no account for this. A simple form of this issue can be illustrated as follows. Suppose each consumer places an (unobserved) premium, More sophisticated methodologies are able to distinguish between market frictions and consumer heterogeneity using more detailed data. Typically, in addition to data on firms' prices and possibly, product characteristics, such studies employ further data on individual consumer's choices over time to estimate switching costs e.g.  or extraA further limitation from the use of a static model also arises from the implicit assumption that consumers are myopic. Consumers only take into account current variables when making their decisions, while ignoring any future expected differences between firms. Most empirical studies ignore these effects but 9To help better understand and measure market frictions, this paper has offered a unified analysis of search costs and switching costs. In its main contribution, the paper has documented the theoretical mechanisms by which the two frictions can affect competition and welfare. Far from being equivalent, these mechanisms are so different that the effects of the two costs can consistently differ in magnitude. Indeed, the paper has shown that, per unit, search costs are often the more anti-competitive and welfare-damaging. While the optimal policy intervention will also depend upon the associated resource costs, this suggests that, in response to the concerns about market frictions in markets such as those for banking in Europe, the benefits from reducing search costs may outweigh the benefits from reducing switching costs.As a secondary contribution, the paper has used insights from the theoretical model to construct separate empirical measures for search costs and switching costs. It has also highlighted the importance of accounting for both frictions in empirical work by showing how some ‘single-cost’ measures can exhibit an upward bias.Overall, it is hoped that the paper may prompt researchers to think further about search costs and switching costs. Empirically, we hope that future work will continue to develop more sophisticated estimation methodologies that account for the existence of both costs. Theoretically, the finding that search costs are often particularly anti-competitive and welfare-damaging underlines the importance of consumer search as an ongoing and increasingly active field of study. Finally, it is hoped that our results could also be extended to help explore the role of search costs and switching costs in labour markets.


These results highlight the ease of spread of this group of H9N2 viruses between domesticated poultry and sparrows and show that sparrows need to be considered as a high risk species for transmitting H9N2 viruses between premises.Genetic changes in avian influenza viruses influence their infectivity, virulence and transmission. Recently we identified a novel genotype of H9N2 viruses in widespread circulation in poultry in Pakistan that contained polymerases  and non-structural (NS) gene segments identical to highly pathogenic H7N3 viruses. Here, we investigated the potential of these viruses to cause disease and assessed the transmission capability of the virus within and between poultry and wild terrestrial avian species. Groups of broilers, layers, jungle fowl, quail, sparrows or crows were infected with a representative strain (A/chicken/UDL-01/08) of this H9N2 virus and then mixed with naïve birds of the same breed or species, or different species to examine transmission. With the exception of crows, all directly inoculated and contact birds showed clinical signs, varying in severity with quail showing the most pronounced clinical signs. Virus shedding was detected in all infected birds, with quail showing the greatest levels of virus secretion, but only very low levels of virus were found in directly infected crow samples. Efficient virus intra-species transmission was observed within each group with the exception of crows in which no evidence of transmission was seen. Interspecies transmission was examined between chickens and sparrows and  There are seventeen antigenically distinct haemagglutinin (HA) and ten neuraminidase (NA) subtypes of influenza A viruses ,2. With The continued circulation of novel reassortant H9N2 viruses depends on many factors but the efficiency of transmission within and between susceptible species is key. A number of studies describe the infectivity and transmissibility of different LPAI and HPAI viruses in different poultry and related land-based wild bird species ,24-26 buGallus gallus, broilers, layers, and jungle fowl; Coturnix coturnix, the common quail; Passer domesticus, the house sparrow; and Corvus splendens, the house crow) and between species, from infected broilers to naïve sparrows and vice versa. The choice was made to represent the breeds of poultry reared in commercial and backyard flocks, and wild-bird species that routinely intermingle with poultry in the Middle East and parts of the Indian sub-continent.To date, limited data are available that describe the relative infectivity and transmissibility of H9N2 viruses in different poultry breeds and terrestrial wild bird species. Here, we examined the infection and transmission of a novel genotype of H9N2 virus that was first detected in 2005 and representative of viruses now circulating in poultry in Pakistan and neighbouring Iran, Afghanistan and other regions of Middle East ,19,21. T50) were determined by the Reed and Muench method [The UDL-01/08 H9N2 virus was a field isolate made in University of Veterinary and Animal Sciences, Lahore, Pakistan. The intravenous pathogenicity index (0.00), antigenic and genetic properties (accession no. CY038455 to CY038462) of this virus have been reported . Virus sh method .Coturnix coturnix) were acquired from a local supplier. House sparrows (Passer domesticus) and house crows (Corvus splendens) were captured from the wild in the surrounding areas of Lahore, Pakistan. Blood, and buccal and cloacal swab samples were taken from all birds and analysed by haemagglutination inhibition (HI) and virus isolation (VI) in 9-day-old EHE using standard methods [ad libitum, and general animal care was provided by the animal house staff as required for each species.Three-week-old white leghorn , broiler chickens , red jungle fowl (hen pullets) and common quail  and buccal and cloacal swabs were taken at regular intervals on 2–7, 9, 11, 15, 19, 23, 27 and 29 days post infection (dpi). Each experiment lasted for a maximum of four weeks and all surviving birds at end of the experiment were humanely killed.In each experiment, each species of birds were divided into two groups, an infected group and a contact group. For experiments in which transmission within a species or bread was investigated, each infected group contained ten birds and each contact group contained five birds, housed in cages of 2.23 mBuccal and cloacal swabs collected in 1 mL of 15% BHIB with antibiotics (10 000 IU/mL Pencicillin G + 100 μg/mL Gentamycin + 20 μg/mL Amphotericin B) were kept on ice, and then filtered through a 0.2 μm filter. The filtered material was divided into two aliquots and stored at -80°C until virus isolation.Virus isolation was performed by inoculating swab samples into 9-day-old EHE and the presence of virus in the allantoic fluids was determined by virus haemagglutination activity using standard procedures .Blood samples from all birds were collected one day before infection (pre-infection) and on 7, 14, 21, 28 dpi for determination of HI antibody titres against H9N2 virus challenge using the standard HI test .P values) between the groups were compared using one-way analysis of variance (ANOVA) and Turkey’s multiple comparison test.Statistical analysis and graphical presentation was performed using GraphPad Prism 6 software. H9N2-specific antibodies titres in serum were calculated as geometric means and viral titres in buccal and claocal swabs were calculated as medians with standard deviations. Statistical significance  in the serum samples recovered from this control group just before termination of the experiments.The analysis of pre-inoculation swab and serum samples by virus isolation and HI tests revealed that all birds used in this study had no detectable infection with H9, H7 or H5 viruses and the levels of HI antibody titres were < 2 Log6.6 EID50 of UDL-01/08. After four hours, the infected birds were co-housed with an additional five naïve uninfected birds of same species in the same cage.Clinical signs and the susceptibility and transmission of H9N2 virus from infected to naïve contact birds in different species was examined following the inoculation of groups of ten birds  with 10Considerable variation in clinical disease signs  were observed depending on breed of chickens and wild bird species infected directly with UDL-01/08 or by contact infection from infected birds. The number of birds in each group that showed clinical disease signs is summarised in Table All 10/10) of the broilers and layers were successfully infected and the presence of virus both the buccal cavity and cloaca was from 3 dpi which resolved by days 11 or 15. Only eight of the ten broilers showed clinical signs; these varied in severity and the signs that were apparent were only observed on days 3 to 5. All layers also showed clinical signs, with the disease signs observed between days 1 to 5, but with the majority of signs being seen, like in the broilers, on days 2 to 5  sparrows had virus in their buccal and cloacal cavities from 3–8 dpi and all contact broilers showed presence of virus in both buccal cavity and cloaca on 6–8 dpi. These results indicate that virus can pass from sparrows to broilers and 3.5 EID50/mL  in buccal swabs of infected broilers and 101.9 EID50/mL  in contact sparrows. Median viral titres in buccal swabs were 102.2 EID50/mL  on 3 dpi in infected sparrows and 103.2 EID50/mL  on 4 dpi in contact broilers . The cloacal swabs recovered from the infected sparrow group and the contact broiler group contained median viral titres 103.4 EID50/mL  and 102.6 , respectively  and 105.0 EID50/mL , respectively, which were significantly greater (p < 0.05) than the viral titres observed in buccal and cloacal swabs taken from broilers and sparrows  virus from oral route compared with broilers and quail but there were no significant differences (P > 0.05) in cloacal shedding between infected sparrows and broilers; thereby efficient virus transmission was possible between infected sparrows and contact chickens.In order to determine levels of virus replication in the respiratory and gastrointestinal tract in infected broilers and contact sparrows, infected sparrows and contact broilers, and infected quail, six virus positive buccal and cloacal swabs taken on 3 dpi from infected birds and 4 dpi from contact birds were titrated in EHE. Median viral titres were 102 HI geometric mean titre (GMT). Infected crows were positive for HI antibodies from 21–28 dpi with of 6.9 – 7.7 GMT. In contact groups, broilers showed the presence of antibody from 7–28 dpi and layers, jungle fowl, quail and sparrows contained positive HI titres from 14–28 dpi. No antibodies against H9N2 virus were detected in the contact crow group, suggesting that crows are relatively resistant to H9N2 infection and inter-host transmission of H9N2 viruses in crows is inefficient compared with that observed in chickens, quail and sparrows.Detection of virus-specific antibodies in infected animals was examined as evidence for the establishment of infection. Serum samples taken from both the directly inoculated groups and the contact groups at one day before infection (pre-infection samples), 7 dpi, 14 dpi, 21 dpi and 28 dpi were analysed by HI assays  and non-structural (NS) gene segments identical to H7N3 virus, is prevalent in poultry in regions of the Indian subcontinent and the Middle East ,19,21. TUnder our experimental conditions, it is highly likely that chickens, quail and sparrows showed clinical disease signs directly due to H9N2 virus infection and not with secondary infections. Importantly, the birds in the control uninfected group remained healthy throughout the experiment and showed no apparent clinical disease signs. Nevertheless, we have not undertaken tests to screen these birds for any subclinical disease. Previously, it was widely believed that H9N2 infections are not the main cause of the induction of disease signs in chickens, but instead farm conditions  were important contributing factors for higher morbidity and mortality -37. LikeOur data indicate that sparrows are highly susceptible to H9N2 infection and infected sparrows can transmit virus not only to contact sparrows but also to contact chickens. However, crows were relatively resistant to H9N2 virus infection and showed only very low levels of virus multiplication resulting in a low amount of virus being shed and no virus transmission to contact crows. Our studies did not quantify very low levels of virus RNA in the swabs by real-time PCR which was not used in the analyses; moreover, the quantitative results for virus infectivity shown in Figure vice versa suggest a worrying scenario in which quail and sparrows could be potential intermediate hosts for maintenance of viruses and the transmission of these viruses to poultry. Crows seem less of a problem because, although they became infected, they did not transmit the virus to contacts and had only low virus titres in swabs. In light of these results, there is a need for increased surveillance of circulating H9N2 and other low pathogenicity AIV such as the novel H7N9 viruses detected in poultry, ducks and pigeons in China, a virus with six RNA segments derived from H9N2 viruses [In conclusion, our results indicated that reassortant H9N2 viruses currently circulating in the Indian sub-continent and the Middle East can cause clinical disease in experimentally infected commercial and backyard chicken breeds as well as in quail and house sparrows. Our observations of efficient transmission between different chicken breeds, from quail to quail, and from chickens to sparrows or  viruses ,52. FurtNS: Non-structural; HA: Haemagglutinin; NA: Neuraminidase; HPAI: Highly pathogenic avian influenza; UDL-01/08: A/chicken/UDL-01/08; EHE: Embryonating hens’ eggs; EID50: 50% egg infectious dose; HI: Haemagglutination inhibition; VI: Virus isolation; dpi: Days post infection; BHIB: Brain heart infusion buffer; GMT: Geometric mean titre.The authors declare that they have no competing interests.Conceived and designed the experiments: MI, JWM. Performed the experiments: TY, NM, MZS. Analysed the data: MI, TY, NM, MZS, JWM. Wrote the paper: MI, JWM. All authors read and approved the final manuscript.Clinical disease signs and presence of virus in buccal and cloacal swabs collected from infected and contact broilers. Infected broilers were inoculated with 106.6 EID50 UDL-01/08 virus and after four hours the uninfected contact broilers were mixed in the same cage with the virus inoculated broilers. Swab samples were inoculated in EHE and virus in the harvested allantoic fluid was detected by HA assay. Y, denotes presence of clinical disease signs and presence of virus in buccal and cloacal swabs. -, denotes absence of clinical disease signs and virus in buccal and cloacal swabs.Click here for fileClinical disease signs and presence of virus in buccal and cloacal swabs collected from infected and contact layers. Infected layers were inoculated with 106.6 EID50 UDL-01/08 virus and after four hours the uninfected contact layers were mixed in the same cage with the virus inoculated layers. Swab samples were inoculated in EHE and virus in the harvested allantoic fluid was detected by HA assay. Y, denotes presence of clinical disease signs and presence of virus in buccal and cloacal swabs. -, denotes absence of clinical disease signs and virus in buccal and cloacal swabs.Click here for fileClinical disease signs and presence of virus in buccal and cloacal swabs collected from infected and contact Jungle fowl. Infected Jungle fowl were inoculated with106.6 EID50 UDL-01/08 virus and after four hours the uninfected contact Jungle fowl were mixed in the same cage with the virus inoculated Jungle fowl. Swab samples were inoculated in EHE and virus in the harvested allantoic fluid was detected by HA assay. Y, denotes presence of clinical disease signs and presence of virus in buccal and cloacal swabs. -, denotes absence of clinical disease signs and virus in buccal and cloacal swabs.Click here for fileClinical disease signs and presence of virus in buccal and cloacal swabs collected from infected and contact quail. Infected quail were inoculated with106.6 EID50 UDL-01/08 virus and after four hours the uninfected contact quail were mixed in the same cage with the virus inoculated quail. Swab samples were inoculated in EHE and virus in the harvested allantoic fluid was detected by HA assay. Y, denotes presence of clinical disease signs and presence of virus in buccal and cloacal swabs. -, denotes absence of clinical disease signs and virus in buccal and cloacal swabs.Click here for fileClinical disease signs and presence of virus in buccal and cloacal swabs collected from infected and contact sparrows. Infected sparrows were inoculated with 106.6 EID50 UDL-01/08 virus and after four hours the uninfected contact sparrows were mixed in the same cage with the virus inoculated sparrows. Swab samples were inoculated in EHE and virus in the harvested allantoic fluid was detected by HA assay. Y, denotes presence of clinical disease signs and presence of virus in buccal and cloacal swabs. -, denotes absence of clinical disease signs and virus in buccal and cloacal swabs.Click here for fileClinical disease signs and presence of virus in buccal and cloacal swabs collected from infected and contact crows. Infected crows were inoculated with 106.6 EID50 UDL-01/08 virus and after four hours the uninfected contact crows were mixed in the same cage with the virus inoculated crows. Swab samples were inoculated in EHE and virus in the harvested allantoic fluid was detected by HA assay. Y, denotes presence of clinical disease signs and presence of virus in buccal and cloacal swabs. -, denotes absence of clinical disease signs and virus in buccal and cloacal swabs.Click here for fileMean viral titers in buccal and cloacal swabs taken from the infected groups on 3 dpi and from contact groups on 4 dpi. Viral titres are presented as log10 EID50/mL determined in EHE inoculated with buccal and cloacal swabs taken from the infected groups on 3 dpi and from the contact groups on 4 dpi. SD, denotes standard deviation.Click here for file


Pediatric antiretroviral therapy (ART) has been shown to substantially reduce morbidity and mortality in HIV-infected infants and children. To accurately project program costs, analysts need accurate estimations of antiretroviral drug (ARV) costs for children. However, the costing of pediatric antiretroviral therapy is complicated by weight-based dosing recommendations which change as children grow.We developed a step-by-step methodology for estimating the cost of pediatric ARV regimens for children ages 0–13 years old. The costing approach incorporates weight-based dosing recommendations to provide estimated ARV doses throughout childhood development. Published unit drug costs are then used to calculate average monthly drug costs. We compared our derived monthly ARV costs to published estimates to assess the accuracy of our methodology.The estimates of monthly ARV costs are provided for six commonly used first-line pediatric ARV regimens, considering three possible care scenarios. The costs derived in our analysis for children were fairly comparable to or slightly higher than available published ARV drug or regimen estimates.The methodology described here can be used to provide an accurate estimation of pediatric ARV regimen costs for cost-effectiveness analysts to project the optimum packages of care for HIV-infected children, as well as for program administrators and budget analysts who wish to assess the feasibility of increasing pediatric ART availability in constrained budget environments. Currently, 3.4 million children are living with HIV throughout the world . Early aTo inform the scale-up of pediatric HIV care in the context of budget constraints, policy makers need accurate projections of antiretroviral drug (ARV) costs and a clear analysis of the cost-effectiveness of alternative ART strategies -8. Thereet al. completed a similar analysis for two dedicated pediatric care sites in South Africa, and further calculated the proportion of total treatment costs pertaining to ART costs [Pediatric antiretroviral therapy use is further complicated by the need for increasing drug doses as children grow. Patients must be consistently monitored for changes in weight to ensure that they are receiving adequate doses of each drug to reach therapeutic levels and fully suppress the virus, while also avoiding toxicities related to excess dosing . To evalRT costs . HoweverHere, we propose a step-by-step approach for determining the monthly costs of ARV medications for children ages 0–13 years in resource-limited settings. We use published ARV price lists as a basis, and account for changes in dosing as children grow, as well as the possible lack of availability of pediatric tablets or co-formulations in some settings and for some groups of patients. This methodology can be easily updated using a simple online tool as new ARV prices are released by international agencies ,25 or arTo estimate the monthly cost of specific ART regimens for children ages 0–13 years in resource-limited settings, we developed a 7-step approach.Weight-based doses for pediatric ARV were taken from Annex E of the 2010 World Health Organization (WHO) Pediatric Guidelines and Annex 7 of the upcoming WHO 2013 Consolidated Pediatric and Adult Guidelines . We next identified publicly available unit costs for each medication. Unit costs are defined as cost (in 2012 USD) per tablet, per capsule or per milliliter of liquid formulation. Due to the wide variety of drug prices available to resource-limited countries based on individual agreements with pharmaceutical companies, we used the CHAI May 2012 ceiling price list as the basis for drug cost estimates [2. stimates . These cstimates . Any othstimates . This anCalculation of monthly costs for each medication by weight (Table 3). Assuming an average of 30.4 days in a month, we calculate the monthly cost for each medication by WHO weight band as follows:3. Average daily dose  is found in Table Probability of being in each WHO weight band by age (Table 4). Although most clinical guidelines regarding ARV dosing recommendations are based on a child’s weight, rather than current age [4. rent age , most porent age . Thus, irent age ,31. Bothrent age .HIV) was equal to that of the general population. To examine the impact of these assumptions, we conducted sensitivity analyses in which we recalculated drug costs after varying both the shifted weight distribution z-score (z-scores of -3 to 0) and the coefficient of variation . These parameters can also be modified by use of the online tool.Although few data are available on how the weight distribution of HIV-infected children compares to the weight distribution of the general population of children the same age, one study found that on average, HIV-infected children are of lower weight . To accoUsing these new weight-by age distributions, we calculated Z-scores for the upper and lower bounds of the weight bands used in the WHO dosing recommendations . An automated calculation function in Excel was then used to convert the z-scores into cumulative probability estimates. Finally, the probability of being in each weight band (by age and gender) was calculated as the cumulative probability of being above the upper bound of the weight band subtracted from the cumulative probability of being below the lower bound of the weight band (or the area under the curve within the upper and lower bounds). Assuming an equal proportion of males and females, these final probabilities by gender were averaged to estimate the probability of being in each weight band by age . We then used the newly defined probabilities of being in each weight band by age . To determine the monthly costs of complete ART regimens, we combined the monthly costs by age for each of the component medications. The WHO 2013 HIV treatment guidelines currently recommend a first-line, PI-based regimen (LPV/r + 3TC + ABC or ZDV) for all HIV-infected children less than three years of age. However, previous WHO guidelines had recommended an NNRTI-based regimen for children who had not been exposed to NNRTIs to prevent mother-to-child transmissions, and in many countries, NNRTI-based regimens remain the most readily available first-line option for children. Here, we present examples of monthly regimen cost calculations for six commonly used ART regimens: lopinavir/ritonavir (LPV/r) with zidovudine (ZDV) and lamivudine (3TC), LPV/r with abacavir (ABC) and 3TC, LPV/r with stauvudine (d4T) and 3TC, nevirapine (NVP) or efavirenz (EFV) with ABC and 3TC, NVP or EFV with ZDV and 3TC, and NVP or EFV with d4T and 3TC. Although d4T is no longer recommended as a first-line medication, it remains an option to use in case of anemia where access to ABC is limited; d4T is commonly used throughout Africa, largely because of its availability in inexpensive FDC formulations [6. ulations ,35.For each regimen, we derived costs for three key scenarios that reflect setting-specific variations in the availability of co-formulated FDCs and the age at which children are assumed to transition from liquid to tablet formulations:Scenario 1 : Coformulations are not available. Liquid formulations of all drug components are used until 4 years of age, and then children switch to pediatric/adult tablets as recommended by weight-based dosing.Scenario 2 : Coformulations are not available. Liquid formulations of all drug components are used until 6 months of age, and then children switch to pediatric/adult tablets as recommended by weight-based dosing.Scenario 3 : Coformulations are available. Coformulated pediatric tablets, if they exist, are used from birth. If all drug components are not included in the coformulation, liquid formulations of the remaining drugs are used until 6 months of age, and then children switch to pediatric/adult tablets as recommended by weight-based dosing.For example, South Africa currently has access to most pediatric liquid and tablet formulations, but co-formulations are not widely available ,18. TherComparison of derived to published costs. After completion of the six steps above, we compared our calculated monthly ART costs (by weight) to other published costs. The WHO has compiled a Global Price Reporting Mechanism (GPRM) database, which contains average yearly costs for both adult and pediatric ARVs, based on international transactions of HIV, tuberculosis and malaria medications purchased in resource-limited settings [7. settings . Costs fWeight-based doses for each antiretroviral drug (Table1). Table 1. Assignment of unit costs for each antiretroviral drug (Table 2). Unit costs for each drug, using CHAI and MSF costs as an example, are shown in Table 2. Calculation of monthly costs for each medication and weight band (Table3). With daily dosing recommendations and unit costs by drug, we then calculated monthly costs for each drug, stratified by weight band. Monthly costs for each drug formulation are shown in Table 3. Probability of being in each WHO weight band by age (Table4).The probability of being in each WHO weight band by current age and gender was calculated as described in the Methods. Results are shown in Table 4. HIV) also demonstrated minimal change in monthly drug costs estimates. First, assuming that SHIV was equal to half the coefficient of variation of the general population, we found that monthly drug costs changed by 4.2%, on average. Second, assuming SHIV was double the coefficient of variation of the general population, we found that monthly drug costs changed on average by 6.4%.Sensitivity analyses on weight distributions demonstrated that monthly drug cost estimates were fairly robust to changes in assumptions regarding the weight distribution for HIV-infected children (z-scores). Assuming no change in weight distribution between HIV-infected children and the general population (z-score = 0), monthly drug costs by age changed on average by 9.7%. Monthly drug costs changed substantially from our original estimates (>10%) only when we assumed much lower weights among HIV-infected children (z-score ≤ -3). With improvements in early infant diagnosis and access to antiretroviral therapy (ART), we anticipate that the growth distribution for HIV-infected children will shift toward the WHO growth curves for the general population, and thus drug costs will remain similar to those calculated in this manuscript. Sensitivity analyses on the coefficient of variation of the weight distribution among HIV-infected children . Using the probabilities of being in each weight band . Monthly costs for complete regimens are shown in Table 6. Comparison of derived to published costs. Compared to the pediatric drug costs reported in the WHO GPRM database (based on children weighing 10 kg), the costs derived in our analysis for children in weight bands 6–9.9 kg and 10–13.9 kg were fairly comparable or slightly higher for most formulations (Table 7. ns Table .et al. focused their analysis on calculating the average cost of HIV treatment care across at two pediatric care sites in South Africa [In this paper, we have provided a standardized methodology for estimating monthly pediatric ARV costs that could allow for greater comparability between future analyses of cost-effectiveness. Our approach incorporates changing dosing requirements as children grow, and accounts for a range of scenarios for the availability of pediatric ARV formulations in different countries and settings. To date, there have been no other published procedures for estimating pediatric ART costs by age and by drug regimen. Meyer-Rath h Africa . They fuIn addition, the WHO has compiled average monthly costs for several pediatric and adult drug formulations in their GPRM database based on records of international transactions of HIV, tuberculosis and malaria products purchased in low- and middle-income countries , focusedOur costing procedure has several limitations. First, we describe a step-by-step approach for calculating drug-related pediatric ART costs. These costs do not take into consideration equipment, personnel, overhead, shipping or opportunity costs that may also be involved in the delivery of ART to pediatric patients. We have also excluded the costs of establishing and maintaining a cold chain store needed for drugs that require refrigeration. The costs of these components are infrequently reported, but will likely inflate LPV/r liquid formulation costs by 5-50% depending on program level cold chain storage capabilities. Although we have chosen to exclude these variable costs from our analysis, the investments needed to establish a cold chain facility may be available at the program level and will be important considerations for program planners to include. In addition, because entire bottles of liquid formulation must be dispensed monthly, often exceeding the total needed quantity, there will likely be some wastage associated with the distribution of liquid drugs. Our current methodology excludes wastage costs, but these will need to be considered by program planners as well. Our costs estimates, however, will allow providers to incorporate drug-related pediatric ART costs into their existing budget and thus permit this methodology to apply to a variety of clinical settings. And finally, pediatric ART costs will likely change over time with the addition of new formulations of existing drugs or the development of new pediatric and adult medications. For example, LPV/r sprinkles and modifiable-dose ARV sachets are currently under development . These fThe number of children living with HIV is growing each year, and will likely continue to grow until efforts to prevent perinatal HIV infection reach target goals . Antiret3TC: Lamivudine; ABC: Abacavir; ART: Antiretroviral therapy; ARV: Antiretroviral; CDC: Center for Disease Control; CHAI: Clinton Health Access Initiative; D4T: Stauvudine; EFV: Efavirenz; FDC: Fixed dose combination; GPRM: Global Price Reporting Mechanism; LPV/r: Lopinavir/ritonavir; MSF: Mèdecins Sans Frontières; NVP: Nevirapine; PEPFAR: The U.S. President’s Emergency Plan for AIDS Relief; WHO: World Health Organization; ZDV: Zidovudine.Dr Holmes was employed by Gilead Sciences from July 2006-January 2008 and was a stockholder during that time. All other authors declare they have no competing interests.AC and KD developed the costing methodology and drafted the manuscript. SR developed the methodology for weight-to-age standards. SE, MP, CH and SR provided critical support to the costing procedure and revising the manuscript. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1472-6963/14/201/prepubCalculate monthly ART costs by regimen and age.Click here for file


Caused by the Zika flavivirus it consisted of a mild and self-limiting illness of rash, low-grade fever, conjunctivitis, headache and myalgia. Two strains of Zika virus were subsequently identified (African and Asian) with transmission via mosquito or sexual contact. Since 2007 there have been several epidemics of the Asian strain including in French Polynesia  and Brazil , and these outbreaks have been associated with increased incidence of Guillain–Barré syndrome (GBS) in adults and microcephaly in infants.Proving a causative link between an infectious agent and subsequent neurological damage is not straightforward. This month’s journal club examines three papers that attempt to provide evidence connecting Zika virus to neurological sequelae. The first is a case–control study of GBS during the Zika virus epidemic in French Polynesia. The second is a prospective cohort study reporting foetal growth defects in pregnant women in Brazil, some of whom had been infected with Zika virus. The third is a cellular paper looking at neural expression of AXL, a receptor that could mediate Zika virus entry into cells.Campylobacter jejuni gastroenteritis being the most common). French Polynesia  typically reports between three and ten cases of GBS per year , but during 4 months of the Zika epidemic (2013–2014) there were 42 cases . This paper compared these 42 consecutive GBS cases with two control groups from the same hospital: first, patients with non-febrile illness (n = 98); second, patients with confirmed Zika virus infection but no neurological sequelae (n = 70). Cases and controls were matched for age, sex, and island of residence.GBS is a rare condition that encompasses various forms of acute immune-mediated polyradiculoneuropathy. It commonly presents as a monophasic, progressive symmetrical weakness with depressed or absent reflexes, often after an antecedent infection  with a median age of 42 years. Clinical characteristics included a viral prodrome (88 % of cases), lag of 4–10 days between viral syndrome and neurological symptoms, symmetric muscle weakness (79 %), areflexia or hyporeflexia (48 %), and facial palsy (79 %). Lumbar puncture showed increased protein only (93 %). Nerve conduction studies showed prolonged distal motor latencies (DMLs) and reduced compound muscle action potential (CMAP) amplitudes at diagnosis, with marked improvement at 3 months following treatment with intravenous immunoglobulin. Sensory potentials were unaffected. Clinical recovery was generally good , although 38 % required intensive care admission for ventilatory and/or nutritional support.C. jejuni, HIV, CMV, and EBV. No association was found between previous dengue infection and GBS.Virological testing revealed IgM against Zika (i.e. evidence of recent infection) in 93 % of GBS cases but just 17 % of non-febrile controls. However, there was no evidence of acute viraemia in any of the cases, consistent with patients rapidly clearing virus and being afebrile at presentation. Important negative serological tests included Comment. This paper shows a convincing correlation between the Zika epidemic in French Polynesia and increased incidence of GBS. The cases are consistent with the acute motor axonal neuropathy (AMAN) subtype of GBS, particularly the relatively preserved reflexes (52 %) and rapid recovery. Zika virus may well be the causative agent, but it is not possible to conclude this from a small observational study. Another unidentified (and untested) aetiological agent could exist. In addition, the controls were suboptimal: control group 1 was selected from non-febrile patients whereas 58 % of the GBS cases had fever as part of a viral prodrome; control group 2 (acute Zika infection) was not tested for Zika IgM/IgG nor followed up to assess for neurological sequelae.Cao-Lormeau V-M et al (2016) Lancet 387:1531–1539.n = 42), but normal in all Zika-negative women tested (n = 16). Various foetal abnormalities were observed including microcephaly (four cases), intrauterine growth restriction (IUGR), cerebral calcifications, oligohydramnios and cerebral blood flow abnormalities. Microcephaly, where present, tended to be part of a wider spectrum of neurodevelopmental problems. There was no specific correlation between gestational age at infection and foetal abnormalities. Interestingly, of the six babies born so far following abnormal ultrasound scans in utero, two have had microcephaly but in conjunction (and proportion) to IUGR, and another has done well following anhydramnios.Phylogenetic analyses suggest that Zika virus was introduced to Brazil in late 2013. The first case was diagnosed in May 2015, and an increase in neonatal microcephaly identified in September 2015. To investigate a possible link between Zika infection and foetal abnormalities, this prospective cohort study recruited 88 pregnant women  who presented with a new maculopapular rash during the epidemic of 2015. Seventy-two patients (82 %) were Zika-positive and had non-specific symptoms such as arthralgia, conjunctival injection, and pruritus. Standard pre-natal care in all 88 women documented immunity to rubella and CMV, a negative syphilis test, and positive dengue IgG  in 88 %. Foetal ultrasonography was abnormal in 29 % Zika-positive women , the numbers are small (particularly the control group), many Zika-positive women refused ultrasonography (42 %), and other causes of microcephaly have not been exhaustively investigated. In particular, other causes of rash (the study’s inclusion criterion) are not explored, and important possible confounding congenital infections such as acute dengue (measured by IgM) or HIV are not documented. In addition, many of the Zika-positive women were from rural, lower income areas, which could implicate other environmental factors.Brasil P et al (2016) NEJM. doi:10.1056/NEJMoa1602412.AXL (previously shown to mediate Zika and dengue virus entry into skin cells) was more highly expressed in radial glia than other receptors. Immunohistochemistry confirmed enrichment of AXL in radial glia and developing human retinal cells when compared to mature neurons. These expression patterns are conserved in mice and ferrets, and can also be seen in human iPSC-derived cerebral organoids suggesting model systems to assay inhibitors of Zika cell entry. A testable hypothesis that the neurotropism of the Zika virus is mediated via AXL is proposed.Zika virus can directly infect human cortical neural progenitor cells in vitro, cause transcriptional dysregulation, and attenuate cell growth. How Zika targets neural progenitors is unknown. The authors postulate that selective receptor expression in radial glia  could mediate Zika virus entry, making these cells particularly susceptible to infection. Single-cell RNA sequencing of foetal human cerebral cortex  enabled typing by genome-wide expression signatures, and assessment of putative Zika virus receptor expression. Multiple possible entry receptor genes were specifically enriched in radial glia, astrocytes, endothelial cells, and microglia. In particular, Comment. This preliminary paper shows that AXL and numerous other putative Zika entry receptors are enriched in various neural cell types, particularly stem cells. It does not show any direct link between Zika virus and AXL, nor does it exclude any of the other receptors as mediators of Zika entry. Further work is needed to investigate how (and whether) AXL is involved in Zika neurotropism and stem cell selectivity, and whether blocking cell entry is a reasonable therapeutic avenue.Nowakowski TJ et al (2016) Cell Stem Cell 18:1–6.Conclusion. The timing of GBS a few days after Zika virus infection, and the discovery of foetal abnormalities following Zika infection in pregnancy similar to those seen in gestational rubella or CMV infections seem to incriminate Zika virus as the aetiological agent. It is, however, very difficult to prove a causative link, as these three papers illustrate. However, whilst larger studies are conducted a lack of scientific proof should not delay public health measures to reduce risk—for example, use of mosquito nets and insect repellent. It should also be remembered that even in the presence of Zika virus infection these remain rare neurological events: the approximate risks of GBS and microcephaly are 0.024 and 1 %, respectively.