Lymphovascular invasion (LVI) and perineural invasion (PNI) are associated with poorer prognosis in several human malignancies, but their significance in gastric cancer (GC) remains to be clearly defined. Our study aimed to investigate the prognostic value of LVI/PNI in patients with curative resected GC.Records of 1488 patients with stage I‐–III GC and 3327 patients with stage I–III colorectal cancer (CRC) were reviewed retrospectively, and difference in the incidence of LVI/PNI between GC and CRC was compared. Univariate and multivariate analyses were used to evaluate whether LVI/PNI was an independent risk factor for lymph node metastasis (LNM) and overall survival (OS) in GC.p  < 0.001). LVI/PNI was significantly associated with higher CEA, higher CA199, deeper tumor invasion, more lymph node metastasis, and advanced TNM stage in GC ( p  < 0.05). Multivariate logistic regression analysis identified LVI/PNI  as an independent risk factor for LNM in GC. The OS rate was significantly lower in the LVI/PNI‐positive GC group than that in the LVI/PNI‐negative GC group ( p  < 0.001). On multivariate Cox regression analysis, LVI/PNI  was an independent prognostic factor for OS in GC.Patients with stage I–III GC had a significantly higher incidence of LVI/PNI than patients with stage I–III CRC (50.54% vs. 21.91%, GC has a high incidence of LVI/PNI, which was closely associated with disease progression. LVI/PNI could serve as an independent risk factor for LNM and the prognosis of patients with curative resected GC. These findings will be helpful in predicting survival outcomes more accurately and establishing individualized treatment plans. Gastric cancer has a high incidence of LVI/PNI, which was closely associated with disease progression. LVI/PNI could serve as an independent risk factor for lymph node metastasis and the prognosis of patients with curative resected gastric cancer. These findings will be helpful in predicting survival outcomes more accurately and establishing individualized treatment plans. In this study, we first compared the difference in the incidence of LVI/PNI between GC and CRC. Then, we analyzed associations between LVI/PNI and other clinicopathologic features in GC. Next, we identified clinicopathologic prognostic factors for lymph node metastasis. Finally, we evaluated the prognostic significance of LVI/PNI in GC patients who underwent curative gastrectomy.22.1This is a retrospective study. Ethical Committee of The Sixth Affiliated Hospital, Sun Yat‐sen University, had approved this retrospective research, and the requirement for written informed consent was waived. Records of 2474 consecutive patients with GC who had surgical resection from January 2009 to May 2021 at The Sixth Affiliated Hospital, Sun Yat‐sen University were reviewed. The inclusion criteria were as follows: (1) primary adenocarcinoma of the stomach confirmed by histopathology; (2) pathologic stage I–III according to the criteria of the American Joint Committee on Cancer TNM staging system (seventh edition)2, ≥18.5 kg/m2), preoperative hemoglobin (HGB) level , preoperative serum albumin level , preoperative carcinoembryonic antigen (CEA) level , preoperative carbohydrate antigen 125 (CA125) level , preoperative carbohydrate antigen 19–9 (CA199) level , tumor location , pathologic TNM stage, LVI, PNI, and most recent follow‐up data. Postoperative telephone follow‐up by the staff of the Cancer Database took place every 6 months up to 3 years, and annually thereafter. Preoperative laboratory tests were routinely performed for cancer patients, including HGB, serum albumin, and tumor markers. Gastrectomy resection specimens are routinely stained with hematoxylin and eosin (H&E) by Department of Pathology, and all specimens were analyzed by two experienced pathologists. LVI was considered positive when there were tumor emboli in lumina of endothelial‐lined spaces on H&E‐stained slides, and PNI was considered positive when tumor cells were found in perineural or intraneural spaces on H&E‐stained slides. In this study, LVI/PNI (+) means whether LVI or PNI was positive, and LVI/PNI (−) means both LVI and PNI were negative. Overall survival (OS) was calculated from the date of surgical resection to the date of last follow‐up or death for any cause.Demographic and clinicopathologic characteristics were obtained from the Cancer Database of The Sixth Affiliated Hospital, Sun Yat‐sen University, including age , sex , body mass index (BMI)  and R software (version 4.0.2). Comparisons of categorical variables between groups were performed using the chi‐square test. Univariate and multivariate logistic regression analyses were used to identify prognostic factors for lymph node metastasis. Univariate and multivariate analyses of prognostic factors for OS in GC were performed using Cox proportional hazards models. Kaplan–Meier curves were generated for OS. Then differences in survival rates between groups were compared using the log‐rank test. All 33.1p < 0.005). Besides, the overall incidence of LVI/PNI in stage I–III GC patients was also significantly higher than that in stage I–III CRC patients  , higher CA199 level (p < 0.001), deeper tumor invasion (p < 0.001), more LNM (p < 0.001), and advanced TNM stage (p < 0.001) were noted compared to those with LVI/PNI‐negative disease. Besides, the incidence of LVI/PNI was increasing in GC patients with advanced T stage or N stage  cases had LVI/PNI‐positive disease and 736 (49.46%) cases had LVI/PNI‐negative disease. As shown in Table e Figure . There w3.3p < 0.05). In multivariate analysis, positive LVI/PNI  was identified as an independent risk factor for LNM in GC. Besides, lower BMI, higher CA199 level, and advanced T stage were also independent risk factors for LNM in GC.As shown in Table 3.4p < 0.001) . Then multivariate analysis further identified positive LVI/PNI  as an independent prognostic factor for OS in GC patients. Besides, age, BMI, CA199 level, CA125 level, T stage, and N stage were also independent prognostic factors for OS of GC patients (p < 0.05).As shown in Table 4Gastric cancer is the fifth most common malignancy and the fourth leading cause of cancer‐related deaths worldwide.For many malignancies, LVI and PNI have emerged as important pathologic features and they have been identified as a harbinger of poor prognosis.GC is often diagnosed at an advanced stage, and LNM is the major diffusion route that predicts a worse prognosis.Prognostic value of LVI/PNI in GC is still under debate. Some researchers argued that LVI/PNI was not an independent prognostic factor despite its strong association with disease progression, including larger size of the neoplasm, deeper tumor invasion, more lymph node metastasis, and more distant metastasis.The major limitation of the current research is its design. It was a retrospective study from a single institution. Only patients with stage I–III GC who had curative gastrectomy were included in the study, and among them, patients with incomplete data were excluded. All of these can cause bias in the results. In this study, we aimed to demonstrate that GC had an unusually high incidence of LVI/PNI. Due to our limited research conditions, we only compared incidence of LVI/PNI of GC with that of CRC based on the Cancer Database of our hospital. As a supplement, we compared incidence of LVI/PNI of GC with that of other cancers reported by previous works of literature. And the collection time of GC patients and CRC patients was different. These factors might weaken the conclusion. In addition, chemotherapy regimen of patients, including data of neoadjuvant chemotherapy, could not be accurately tracked in the current cancer database and thus was not analyzed, which may have an impact on the survival outcomes in patients with advanced disease.5In conclusion, LVI/PNI is an underreported phenomenon in GC. Our study demonstrated that GC had a high incidence of LVI/PNI, which was closely associated with disease progression. LVI/PNI was identified as an independent risk factor for LNM and the prognosis of patients with stage I–III GC. These findings will be helpful to predict survival outcomes more accurately and establish individualized treatment plans.Fengxiang Zhang: Conceptualization ; data curation ; formal analysis ; investigation ; methodology ; project administration ; resources ; software ; validation ; visualization ; writing – original draft ; writing – review and editing . Huaxian Chen: Conceptualization ; data curation ; formal analysis ; investigation ; methodology ; project administration ; resources ; software ; validation ; visualization ; writing – original draft ; writing – review and editing . Dandong Luo: Conceptualization ; data curation ; formal analysis ; investigation ; methodology ; project administration ; resources ; software ; validation ; visualization ; writing – original draft ; writing – review and editing . Zhizhong Xiong: Data curation (supporting); methodology (supporting); software (supporting); writing – review and editing (supporting). Xianzhe Li: Data curation (supporting); methodology (supporting); software (supporting); writing – review and editing (supporting). Shi Yin: Data curation (supporting); methodology (supporting); software (supporting); writing – review and editing (supporting). Longyang Jin: Data curation (supporting); methodology (supporting); software (supporting); writing – review and editing (supporting). Shi Chen: Conceptualization ; funding acquisition ; resources ; supervision . Junsheng Peng: Conceptualization ; funding acquisition ; resources ; supervision . Lei Lian: Conceptualization ; funding acquisition ; resources ; supervision .This study was supported by the Guangdong Natural Science Fund for Outstanding Youth Scholars (Grant No. 2020B151502067) and National Key Clinical Discipline.The authors have no conflict of interest regarding the content of the article.The current research complies with the standards of the Declaration of Helsinki. Ethical Committee of The Sixth Affiliated Hospital, Sun Yat‐sen University had approved this retrospective research (No. 2022ZSLYEC‐232), and the requirement for written informed consent was waived.


The World Health Organization’s (WHO) Western Pacific Regional Office developed the biennial Healthy Islands Recognition Awards (HIA) in 2009 to reinforce the Healthy Islands vision and encourage countries to continue to innovate and demonstrate effective and efficient ways of promoting and protecting population health. This research aimed to identify characteristics of and challenges for successful health promotion in the Pacific. The research was undertaken to develop practical guidance for other groups in the Pacific Islands interested in supporting Healthy Islands. We used a qualitative case study to review 2013 and 2015 HIA awardees from eight Pacific Island countries and territories using a set of questions drawn from the HIA application criteria. In 2015–2016, 35 key informant interviews and a review of program documents were undertaken. This was followed by a workshop with representatives from three HIA awardees to further develop recommendations. We reviewed eight programs targeting healthy eating, physical activity, healthy settings and sanitation. Using evidence, careful planning, building capacity, developing partnerships, strengthening and reorientating networks, ensuring accountability and conducting evaluation were keys to the success of healthy islands projects. Considering the local setting and community was perhaps the most crucial theme amongst the programs examined. Challenges included funding and capacity constraints, maintaining commitment and prioritisation, maintaining communication and coordination and technical challenges. Success factors, challenges and recommendations aligned well with mainstream health promotion literature, although some important distinctions exist. Further research is needed to guide successful health promotion practice in the Pacific. Yanuca Island Declaration  program was established by the WHO Regional Office for the Western Pacific in 2009 to reinforce the Healthy Islands vision and to encourage communities and countries to continue to innovate and demonstrate effective and efficient ways of promoting and protecting the health of their populations. Visions can be challenging to implement and in 2013, the WHO published a  forward . The WHOMuch of the literature on effective health promotion is based in settings that are contextually different from the Pacific Islands and health promotion literature in the Pacific is scarce. Even though many health promotion programs are delivered on the ground, few are fully evaluated or published in the peer-reviewed literature. The aim of this research was to review 2013 and 2015 awarded programs to identify characteristics of success and challenges for health promotion in the Pacific Islands.A qualitative case study design was utilised, the preferred method when the researcher seeks to investigate in-depth questions on contemporary phenomena where there is little or no control . The suiThe word ‘program’ is used here to describe discrete, planned activities to promote health in various Pacific Island countries and territories. However, this is not intended to perpetuate the myth that health promotion ends when funding runs out. We consider the end point for health promotion interventions to be when the changes sought have become embedded into the systems and structures of society to the extent that related health benefits are continued after the initial program funding ends (adapted from n = 35) were those responsible for coordinating and/or supporting the four HIA awarded programs in 2013 and the four HIA awarded programs in 2015 , was utilised as a framework for direction to appropriate documentation, guidance on the structure and nature of the questions asked in the interviews and to frame the discussion of results.Interviews were audio-recorded, conducted in English  and typically lasted 45 min to 1 h. Three telephone interviews were conducted where a visit was not possible, with questions sent to participants prior to the interview. Interviewers used questions drawn from the HIA application criteria. Participants were also asked to identify potential lessons for those interested in developing similar programs, including perspectives on challenges to effective health promotion in the Pacific and factors influencing sustainability.To provide context and detail to the interview transcripts, documents were obtained from program staff, WHO and websites related to the HIA programs. Documents included HIA applications, organisational and program reports, news articles and website information.Interview data were de-identified, transcribed and stored in an electronic database. Documentation data were collated and stored alongside the interview data. A thematic analysis of primary and secondary data sources was undertaken by CB and EM to describe successful programs within the context of each individual case, followed by a cross-case synthesis. In both of these stages, the simplified health promotion planning and evaluation framework was used to guide the analysis. A draft of the initial findings was prepared, and a workshop was held in June 2016 with, based on availability, representatives from three of the Healthy Islands Recognition Program Awardees. Findings were reviewed and discussed in this workshop. Separately, all participants were offered the opportunity to review and comment on findings to ensure accurate interpretation. Themes are discussed according to the health promotion planning and evaluation framework and illustrated using de-identified quotes.Over 40 documents/websites were reviewed, and 35 interviews (20 women and 15 men) were undertaken over a 5-month period. Eight participants were program leads, while the remaining 27 were implementers and other stakeholders.Program objectives A lack of capacity, especially in terms of funding, resources and staffing, was the most common theme referred by participants and this affected the vast majority of programs.‘There is high demand…but there is not the capacity to provide enough for everyone’. (Interviewee E2)In numerous cases, program and community need exceeded program capacity:As a result, some programs were reliant on short term sources of funding or contracts. Logistical challenges  also affected the reach of some programs. For example, it was very difficult for one program to reach outer islands and such communities were not able to fully benefit from its activities. Participants from one program also cited a particular need for further capacity building of their local volunteers and staff in health promotion and data collection.Commitment to and prioritisation of the program amongst staff, the community and key stakeholders was another theme referred to. For example, one program was severely affected by a typhoon which reoriented community priorities to more immediate concerns during that period of time. Representatives of another program, which was reliant on the work of volunteers, mentioned that motivation from these volunteers ebbed and flowed over time. It was mentioned by participants from two programs that limited commitment from the government was a key challenge, and that initial government support may not necessarily be sustained.In the theme of ‘coordination and communication’, challenges experienced by a small number of programs included maintaining the involvement of key stakeholders after program staff turnover, the need for better coordination between key stakeholders, and the need for improved information systems. For example, participants from one program cited the need to be able to conduct on-going surveys as a way to monitor the effectiveness of the program, which could also inform dialogue with the health department.Some programs experienced other challenges that were unique to their context or specific health issue that they sought to address. For example, variations in access to health care, provision of water, and fresh local foods were occasionally an issue for programs that were dependent on these. In the case of Tokelau, where fizzy drinks were banned, the illicit trade of such beverages has been reported to be a potential challenge .Participants were asked how their programs became successful and how others could emulate this. Their responses are presented within the following stages of the simplified health promotion and evaluation cycle.Three broad themes were identified as contributing to effective situation analysis: building an evidence base; drawing on local practices, experiences and needs; and adapting global targets, issues, tools and approaches.‘When our people have the right information and understanding of their health status, the risk and appreciate where they want to go and the health they wish for, then they are empowered to make healthy decisions’. (Interviewee G1)In most cases, programs assessed the current health situation and its causes by conducting desk-based reviews of scientific and other sources of information, and discussing and sharing this information with their communities. In Tokelau for example, evidence on the prevalence of overweight and obesity from a WHO STEPwise approach to Surveillance (STEPS) survey stimulated action on reducing sugar-sweetened beverages. This was supported by data collected by the Ministry of Health in Tokelau which found that soft drink consumption was approximately 43 L per person per annum .This evidence was presented to the leaders (Taupulega), of each atoll. As a consequence, one atoll (Fakaofo) completely banned carbonated soft drinks in 2011. Local bans were subsequently introduced to Nukunonu and Atafu, and a national policy that banned imported fizzy drinks was introduced in 2013.‘[It’s important to] explain it in the context that it’s from the locally community’s perspective. It’s the reason why [the Island Food Community of Pohnpei] emphasise culture, as opposed to an economic perspective. They use that as an entry point to garner support from the community. In the [Island’s] culture, if you engage in their cultural activities and respect [it], they recognise you’re being serious…it gains your credibility and because of [that] it gives them a means to advocate on your behalf to other communities’. (Interviewee A5)Participants recognised that while evidence is helpful for pointing them in the right direction, local knowledge was also critical for engaging the community and achieving shared responsibility. Local people often have the best understanding of community needs and offered creative solutions . DrawingParticipants explained that linking with global targets, issues, tools and approaches gave them direct access to international best practice. Aspirational targets Participants suggested that in the planning stage, information and partners should be brought together to identify, consider and prioritise possible solutions . For exa‘A major learning for me was planning, planning, planning. We in the Pacific are talking people and we don’t write things down. But I realised how important it was to plan and record as you go along. I use the documents we developed now for other areas. I had more professional growth from being involved in the project than from doing a [university] degree’ (Interviewee B2)Most participants considered a written plan essential for achieving a common understanding of the program goal and strategies . It was They also recommended that the plan detail how the program will be evaluated to measure the overall success of the program but also to inform its delivery along the way. Finally, it was suggested that the ‘plan should be frequently updated, so that it can respond to new information, events, or changes to the health issue’ . Good pl‘One very important thing is collaboration with stakeholders and the partnership with other agencies that are involved…in the market itself, there are lots of issues to be addressed, so there have been meetings with other partners on how we can integrate into a working partnership to help develop the market…the [government health department] does the implementation, but they’ve had a series of meetings with other partners [that are involved in the management of the market]’. (Interviewee H2)To implement a planned program, participants emphasised being realistic and flexible enough to make adjustments where necessary. For example, stakeholders involved with the Tasa Role Models program needed to adjust plans, timelines and budgets after a typhoon caused significant disruption. Another key to implementation was the reorientation of networks, communities and systems. Reorientation helped to embed the changes in the systems (such as the food system) and settings (such as retailers) so that they become the norm. Achieving reorientation required continuous communication, as evident in the Honiara Central Market Healthy Setting Project:‘Project management mechanisms worked really well. It is hard to operationalise multisectoral interventions because organisations have different values. It worked in this project through:An overarching partnership agreement among key implementing partners• Shared logic models• Clear tasks for each organisation• Aligning interests so that the supply side and the demand side were funded• Shared monitoring and evaluation framework.• Ministry of Internal Affairs would write up the work. This documentation of what we were doing created a shared view. Transparent with documentation, budgets, progress reports’.• (Interviewee B3)Building the capacity and number of stakeholders was also key as this led to shared workloads, ownership, as well as expanding the reach of the program and resources. Finally, participants identified accountability as essential for effective implementation. A variety of accountability structures were evident in the programs including management and governance structures, reporting procedures and memorandums of understanding guiding how partners worked together. These structures were not necessarily started from scratch and, in fact, existing structures were used in many cases. The Kau Mai Tonga program provided a good example of implementation that was well planned and that had clear accountability.Participants pointed out the value of evaluation by describing it as telling their story. Some used logic models to help evaluate various stages of the program, including what worked and what didn’t work in terms of process, impacts and outcomes . ParticiA key observation was that program leaders did not wait until the ‘end’ of the implementation period before evaluation commenced. In fact, workshop participants recommended that evaluation is conducted from the beginning, as having baseline data prior to any proposed interventions was vital. For example, in the PEN Fa’a Samoa program, successes measured in pilot villages were important to support the program’s expansion to the national level. Representatives of the Kau Mai Tonga program tested social marketing advertisements in focus groups and reported back to stakeholders before the final version went to air so they could ensure they had messages that resonated with the target audience.A formal, rigorous evaluation was noted by participants as potentially a resource-intensive and overwhelming task for smaller programs in the Pacific. For example, there was little evidence of the use of evaluation frameworks like RE-AIM. To overcome this, workshop participants emphasised to simply ‘start somewhere’  and garner support from other stakeholders. Universities or non-government organisations can bring a wide range of technical expertise to evaluation and may also be able to attract additional resources. In starting on a small scale, the simple observation of children playing on playground equipment built as part of the Tasa Role Models program was used to demonstrate effectiveness. Another strategy was drawing on existing data. The Tokelau program used WHO STEPs data to justify the ban on sugar-sweetened beverages, and further iterations of WHO STEPs data can also be used to evaluate the impact. If existing surveys do not exist, the logistics, infrastructure and expertise of institutions that already run other surveys could still be utilised to either arrange for a new survey to add new questions/measurements to an existing survey.From document analysis and interviews with leaders and representatives of eight health promotion programs, we have described key challenges and success factors in the reviewed health promotion programs in the Pacific to inform best practice. These are summarised in Although framed within the Healthy Islands vision, the factors for success embedded within the programs examined align well with the existing  evidence on what makes for successful health promotion programs. Amongst the programs examined in this study, the need for local community input, engagement, participation, leadership and ownership stood out as critical for success, supporting observations from various other studies in the Pacific region  and the While there are similarities between what works in mainstream health promotion practice and the programs explored in this Pacific study, there are some differences. Capacity and limited resourcing constrain many health promotion programs globally  and therA key strength of this study is the diverse range of programs and participants involved. The programs span various health issues, operated at different levels, were at different stages of the health promotion planning and evaluation cycle, and a wide range of Pacific Island countries and territories were included. Finally, the qualitative case study design enabled rich and detailed data directly from program leaders.Framework of Action for Revitalization of Healthy Islands in the Pacific  was perhaps the most prominent theme. It is important to recognise that this study explored a selection of programs in the Pacific, however, it is far from all-encompassing and nor should all countries, territories, islands and communities of the Pacific be treated homogenously. Whilst this study adds to the scant amount of literature on health promotion on the Pacific, it is explorative and there is a vast need for further research in this area, which should allow for greater coverage of a wider range of health topics/issues and levels  across the various stages of the health promotion and evaluation cycle.This work was undertaken with funding support from the Government of Korea's Ministry of Health and Welfare through the World Health Organization's Division of Pacific Technical Support.


This article reviews the current state of practice in seismic risk mitigation, focusing on policies in ten of the most earthquake-prone countries around the world. In particular, the review compares policies to retrofit existing buildings and mechanisms for financing seismic risk mitigation, within the context of seismic risk and design standards for each country. The goal of the review is to identify policy best practices that may be useful for national and local governments that are interested in improving their earthquake resilience. The result is a set of best practice recommendations that are organized conceptually around key stages of the seismic retrofit process: (1) risk assessment; (2) knowledge transfer; (3) setting targets; (4) implementation; and (5) monitoring. While these lessons may be valuable to any earthquake-prone country, the recommendations are framed with particular attention to the United States where seismic risk mitigation is primarily the responsibility of local governments. China, Older buildings are typically constructed using adobe or masonry without reinforcement, using concrete with insufficient reinforcing steel, using steel with deficient connections, or using wood frames with open ground floors, which make them prone to failure when there is ground shaking. This situation has been improved as new seismic codes were developed to provide higher standards. However, the shortage of technical manpower, the deficiency in regulatory mechanisms to ensure that new construction is fully compliant with seismic codes, and economic constraints may still exist in some countries and lead to inadequate earthquake-resistant capacities of newly constructed buildings.Seismic retrofitting does not usually make older buildings as strong as new ones. Standards typically require that retrofitted buildings have enough capacity to remain standing so occupants can safely evacuate, but those buildings may be damaged beyond repair (ICC 2017a). Current codes for most new buildings target preserving the lives of occupants by minimizing the likelihood of building collapse under significant shaking, i.e., the maximum considered earthquake . Some bu1.1.Although strengthening older buildings helps protect life and property, most building owners are reluctant to make such changes. A seismic retrofit is a major financial investment with no immediate returns on which to capitalize and the value of such an depends on the building’s ability to generate future returns . Moreove2.2.1.The States of California, Oregon, and Washington have the highest risk of earthquake damage in the United States, accounting for 80% of annual nationwide earthquake losses . Out of In contrast to other earthquake-prone countries, seismic risk mitigation policy in the United States is primarily the responsibility of state and local governments. This is because there is no federal mandate for building codes and standards to be adopted across all jurisdictions. Building codes, such as the International Building Code (IBC) and the International Existing Building Code (IEBC) are the foundation for many building codes and standards across the U.S.  1953, the 1994 amendment to the Hospital Facilities Seismic Safety Act of 1983 that mandated the seismic retrofit of hospitals in California . SB 19532.1.1.1.Unreinforced masonry (URM) bearing wall buildings have long been recognized as the most prone to damage structure type in earthquakes. After the 1933 Long Beach Earthquake (M 6.4), the California State Legislature passed the Field Act, which banned the construction of new URM buildings . HoweverThe City of Long Beach passed a mandatory ordinance to strengthen URM buildings shortly after the 1971 San Fernando Earthquake . The ordIn the U.S. state of Washington, the risk of a catastrophic earthquake was not known until the 1990s, when research that uncovered the massive Cascadia Earthquake of 1700 revealed the risk . As the 2.1.1.2.Soft-story buildings are weak at the ground level due to large openings in perimeter walls for garage doors and store windows and few interior partition walls. After the 1989 Loma Prieta Earthquake (M 6.9) and the 1994 Northridge Earthquake (M 6.7), which left thousands of housing units uninhabitable, soft-story buildings were recognized as hazardous. In 2005, the California State Legislature amended the Health and Safety Code and expressly authorized cities to adopt seismic retrofit standards that comply with nationally recognized codes through ordinances. The Code also identified wood-frame, multi-unit residential buildings, constructed before January 1, 1978, with soft, weak or open-front wall lines as potentially hazardous buildings. In 2003, the first edition of the IEBC was published, providing guidelines for “Earthquake Hazard Reduction in Existing Wood-Frame Residential Buildings with soft, weak, or open-front walls.” The Code was amended in a three-year cycle and used as the model code for seismic retrofit in California .P-807 method to provide detailed procedures on seismic analysis and retrofit for vulnerable wood-frame buildings  Program, in which the State provides a grant of $3,000 to homeowners in a few designated areas that are at high risk for earthquakes. The program has been expanded to include more than a hundred zip code areas to date. Eligible houses are made of wood frames with cripple walls . Since 2In addition to state-level incentives, cities in California have employed various financial measures to promote seismic retrofit. The City of Almeda offers up to 100% fee waiver for engineering report review and construction permits for soft-story buildings. The City of Berkeley provides a retrofit grant that covers up to 75% of design and 40% of construction costs for non-ductile or tilt-up concrete buildings and soft-story buildings with three or four units. URM and soft-story buildings with five or more units can receive a grant that covers up to 75% and 30% of design and construction costs, respectively. The Cities of Fremont and Pasadena waive plan review and building permit fees and construction taxes as they have relatively few soft-story buildings. The City of San Francisco allows soft-story building owners to pass 100% of total seismic retrofit cost to tenants over 20 years, whereas the City of Los Angeles limits the amount to 50% of retrofit cost, passed to tenants over 10 years.2.2.New Zealand is located along the boundary between the Indo-Australian Plate and the Pacific Plate. Every year over 15,000 earthquakes are detected in New Zealand, and about 100 to 150 of these quakes are large enough to be felt. Historical trends and records suggest that New Zealand would experience several magnitude 6 earthquakes every year, a magnitude 7 earthquake every decade, and a magnitude 8 earthquake every century .Similar to the U.S., seismic design standards and retrofit policies are adopted at the local jurisdiction level. However, unlike the U.S., the national government can mandate adoption or development of a code or standard. After the 1931 Napier Earthquake (M 7.7), New Zealand developed its first seismic code. By 1979, a patchwork of building codes and bylaws was administered across several layers of central and local government . The Bui2.2.1.The Building Act 2004, the first regulation addressing existing buildings, recommended that the minimum level for seismic retrofit of existing buildings should be 34% of the code requirement for a new building standard (denoted 34% NBS). The Building Code for new construction is contained in the Act. A 34% NBS represents the minimum requirement necessary for ensuring safety in an earthquake event. A score lower than 34% NBS indicates high risk, while a score greater than 34% NBS implies moderate risk. The New Zealand Society for Earthquake Engineering argues that 67% NBS is a more suitable minimum level for seismic retrofit, because the Act’s minimum requirement (34% NBS) is inadequate to eliminate non-ductile failure in earthquake-prone buildings. A score of 67% NBS or above is typically considered a minor risk . DependiThe Building Act 2004 also stipulated that altering or changing the use of an existing building should comply with the Building Code for new construction. Moreover, local or territorial authorities were mandated to develop a policy to mitigate earthquake risks for their jurisdictions. By 2013, 73% of territorial authorities adopted seismic retrofit levels between 33% and 67% NBS, and 27% of them approved 67% NBS. In addition, 45% of local authorities chose an active approach to implement retrofit policies, 32% of them used a passive approach, and 23% of them employed a combined active-passive approach. The active approach includes a rigorous identification and detailed assessment of potential hazardous buildings and time limits for retrofitting or demolishing those buildings. The passive approach requires structural strengthening when alternating or changing the use of an existing building .The Christchurch Earthquake (M 6.2) in February 2011, part of the 2010–2011 Canterbury Earthquake Sequence (CES), resulted in 185 fatalities and substantial damage due to its proximity to the central business district . The CES2.2.2.New Zealand established the Heritage Earthquake Upgrade Incentive Programme (EQUIP) in 2016 to support earthquake strengthening work for heritage buildings. Owners of heritage buildings can receive a grant from EQUIP that covers up to 50% of retrofit cost. Some local authorities, such as the Cities of Dunedin, Auckland, and Wellington, offer additional incentive funds to non-heritage buildings, but such assistance programs only exist in large cities where building owners are relatively wealthy and able to pay retrofit costs. This leads to a high retrofit rate in cities, but a low rate in small towns as they cannot afford strengthening costs . Thus, n2.3.Many cities in Japan are located on coastal plains formed by sandy sediments and clay soil deposits at the mouths of rivers, which are weak and tend to liquefy during earthquakes. The Tokyo metropolitan area, the capital of Japan, is located on three layers of plates that rub or collide frequently, causing massive earthquakes. The probability of a magnitude 6 or stronger earthquake occurring in the next 30 years is 45 to 70% for the Tokyo metropolitan area (Headquarters for Earthquake Research Promotion 2018).Japan has uniform national building standards implemented by both the national and local governments. Building standards are defined under the Building Standard Law, which facilitates compliance and control and ensures minimum specifications for safety . This isIn 1971, Japan amended the Building Standard Law and improved seismic design standards for reinforced concrete structures in response to the 1968 Tokachi Earthquake (M 8.3). Shortly thereafter, the 1978 Miyagi Earthquake (M 7.7) hit the northern region of Japan and caused the collapse of many buildings constructed under the 1971 Building Standard Law. In response, Japan modified design standards to not only prevent the collapse of buildings but also to secure the safety of people inside buildings during earthquakes, which enabled buildings constructed after 1981 to resist earthquakes that are one level higher (M 6) compared to previous requirements (M 5).2.3.1.Retrofit policy in Japan targets buildings by occupancy. The catalyst for modern retrofit policy was the 1995 Great Hanshin-Awaji Earthquake (M 6.9), which was centered in the southern region of Japan and resulted in 6,437 deaths and the collapse of 100,000 houses. A post-earthquake study reported that 76% of the collapsed buildings were constructed before 1971 and 21% between 1971 and 1981. This demonstrated that updating design standards alone is not enough to secure the safety of people and property. As a result, Japan adopted a set of provisions, including “The 1995 Act for Promotion of the Earthquake Proof Retrofit of Buildings” and “The 1998 Act for Support for Reconstructing Livelihoods of Disaster Victims,” to promote and support seismic retrofit for buildings constructed before 1981 .The 1995 Seismic Retrofitting Promotion Law provided measures and guidelines for identifying and strengthening seismically deficient existing buildings. The Law also contained retrofitting targets devised by the national government, such as raising the proportion of seismic-resistant houses and designated buildings  to 75% and 80% by 2003 and 2008, respectively. The Law was amended in 2005 to include the retrofitting promotion plans of local governments. Local governments tailored retrofitting targets to their conditions and needs, planned actions to be taken to achieve those targets, and designated emergency routes and evacuation facilities for their territories. In addition, the Ministry of Education, Culture, Sports, Science & Technology (MEXT) established policies for the structural and nonstructural retrofit of schools in Japan . The LawThe procedure for determining whether to retrofit or demolish a building in the diagnosis stage is as follows. A building that has an earthquake-resistant capacity equivalent to or above 60% of the requirement for new construction does not require strengthening. The decision to retrofit is affected by preservation needs, the target level of retrofitting, the availability of retrofitting methods, the costs of retrofit and demolition, the level of satisfaction with the building’s current functions and facilities, and the plan for future use of the building.2.3.2.Japan has implemented a system of financial incentives to encourage buildings owners to carry out needed retrofit measures see . For detJapan conducts various surveys to acquire data for formulating housing-related policy measures, including the Housing and Land Survey, Building Dynamic Statistics Survey, Comprehensive Survey of Living Conditions, and Housing Market Trend Survey . For insIn addition to promoting building owners to comply with current building standards, Japan provides financial incentives for meeting higher than the mandatory standard. The Government Housing Loan Corporation, which provides long-term, low-interest loans for new construction, renovation, and retrofit, has established technical criteria beyond the mandatory minimum standard of the Building Standard Law. This enables buildings to achieve higher structural performance in a sustainable way, because enhanced construction quality triggers additional financing from private banks, and additional financing can fill funding gaps to ensure the completion of construction.2.4.Italy faces substantial seismic risk due to its position in the Mediterranean where the African and Eurasian tectonic plates converge . From 19The first seismic provision in Italy was issued in 1909 after the great Messina Straits Earthquake. The provision was revised several times, and the 1974 version can be considered the first modern building code. After the 1980 Irpinia Earthquake (M 6.9), a new seismic classification method was introduced into the seismic provision. Based on this method, about 45% of the Italian territory was classified in Seismic Zones 1, 2, and 3.2.4.1.Italy has one of the world’s oldest building stocks, with a large number of unreinforced masonry (URM) and reinforced concrete (RC) buildings. In the northern cities of Concordia della Secchia and Mirandola, for example, URM buildings account for about 87% and 70% of the building stock, respectively . Such buThe first seismic code addressing existing buildings was published in 1986, and the code did not change substantially until 2003, when a new code based on Eurocode 8 was drafted and enacted. Eurocode 8 (EN 1998) is a harmonized technical rule that applies to the design and construction of buildings and civil engineering works in seismic regions. The code consists of six parts dealing with different types of construction, with EN 1998–3 providing technical standards for the seismic assessment and retrofit of existing buildings. The code defines basic performance requirements for structures under three limit states , and provides compliance criteria including ensuring that the demands do not exceed corresponding capacities at each limit state. The code also depicts the information needed and the methods used for structural analysis, as well as safety verification criteria for reinforced concrete structures .The 2008 update introduced the “local strengthening” method for both public construction and private buildings to enable strengthening single structural elements or portions of a structure, without varying the global structural behavior. Moreover, a new seismic hazard map created using the micro-zonation method was adopted for a better identification of seismic hazards . InitialShortly after the enactment of the 2003 seismic code, Ordinance No. 3274 required local governments to complete seismic safety verification for all public strategic buildings and infrastructure in medium and high hazard regions within five years. The Law 326, enacted the same year, allocated a fund of €200 million to support the verification and seismic retrofit for buildings found deficient. By 2012, the number of verified buildings was far short of the requested 35,000, and thus the government decided to use the list of buildings to be verified to support the ongoing National Seismic Prevention Program . The maj2.4.2.After the 2009 Abruzzo Earthquake, the Law 77 granted €1 billion to the Department of Civil Protection for a seven-year National Seismic Prevention Program. The program funded seismic micro-zonation studies, retrofitted or reconstructed public strategic buildings and infrastructure, strengthened or reconstructed private buildings that are used by a large number of people, and developed emergency management tools and plans for urban communities . By 2018In 2017, Italy adopted the “Sismabonus” (or “quake bonus”), a tax incentive policy to motivate building owners to strengthen their buildings . The pol70% for independent/detached houses or manufacturing buildings that improve one class of risk;80% for independent/detached houses or manufacturing buildings that improve two or more classes of risk;75% for apartments that improve one class of risk;85% for apartments that improve two or more classes of risk.The Italian government grants tax reimbursements to building owners as follows:The amount of tax reimbursement cannot exceed 96,000 Euros for each real estate unit . While cFinally, Italy also encourages building owners to improve energy efficiency along with the seismic upgrade of existing buildings . Similar2.5.Like Japan, China defines building standards under the Law to enforce compliance. The first seismic design standard (GBJ 11–89) came into effect in 1989. The standard was updated every ten years with minor amendments in between. Between the 1950s and 1980s, a large number of masonry and reinforced concrete buildings were constructed, designed to resist gravity loads without considering the effect of seismic loads. Today, those older buildings not only fail to meet seismic requirements, but are also subject to degradation due to aging and are unfavorable for energy conservation .China is one of the most seismically active countries in the world, as it lies on multiple active tectonic plates. The most devastating earthquake in recent decades, the 1976 Tangshan Earthquake (M 7.6), hit the most densely populated region of the country. More than 242,000 people died, 85% of buildings collapsed or were unusable in the City of Tangshan, and 10% of buildings collapsed in the capital, Beijing. In response, Beijing established an Earthquake Risk Reduction Council to repair damaged buildings and strengthen vulnerable structures in its district . More re2.5.1.Similar to Japan, retrofit policy in China targets buildings by occupancy and potential earthquake risk. In China, the Department of Building and Development is responsible for building regulation and code enforcement. The Department issues the National Plan for Earthquake Hazards Reduction every five years. The 2016 Plan included the objectives of advancing the regulatory system, identifying high-risk buildings, retrofitting or reconstructing hazardous public buildings and residential buildings, strengthening heritage buildings, using informative tools to support seismic risk management, and promoting the development and deployment of earthquake-resistant techniques .2.5.2.In China, the cost for seismic retrofit, as well as the cost for improving building energy efficiency and upgrading non-structural components, is fully funded by local governments. Buildings are retrofitted based on government plans and budgets, which saves building owners time and money in submitting retrofit plans and applying for building permits. However, this policy greatly increases the financial burden of governments and hence has been implemented in a limited number of communities. By the end of 2017, Beijing had retrofitted more than two million square meters (21 million square feet) of housing .In 2016, the Chinese central government initiated a five-year plan to improve the seismic safety of high-risk buildings across the country. Since the plan was drafted at the national level, it allowed for allocation of funding and resources to urgent projects, such as buildings that were most vulnerable to earthquakes, or under-developed areas where local governments could not afford large-scale retrofitting . Moreove2.6.Iran is located on the active Alpine Belt. From 1990 to 2005, Iran experienced 14 earthquakes of magnitude 7.0 or above and 51 earthquakes of magnitude 6.0 to 6.9, which claimed more than 180,000 lives in total. Adobe and masonry buildings are the major type of structure in Iran and suffered the highest level of damage in historical earthquakes . After tThe first Iranian Code of Practice for Seismic Resistant Design of Buildings was published in 1988, also known as Iran national standard No. 2800. The mandatory code has been updated three times, and the current version was released in 2015. Post-earthquake studies indicated that the damage rate of buildings constructed after 1990 is significantly lower than that of older buildings . In 19972.6.1.Iran established a national earthquake hazard mitigation program in 2000, aiming to improve the resilience of critical buildings and lifelines across the country. The main objective of the “Doable Initiative and Momentum for Earthquake Hazard Reduction” was achieving seismic safety in Iran by 2020 . In 2003In Iran, most retrofit activities occur for critical structures , whereas older residential buildings are typically demolished and reconstructed because retrofitting is time-consuming and costly . In 20042.6.2.In 2007, the Iranian Parliament granted 4 billion U.S. dollars to reconstruct or retrofit those hazardous schools . The Hou2.7.Turkey is located in a seismically active area where the Eurasian Plate collides frequently with the African and Arabian Plates. Two major fault lines, the North Anatolian Fault and East Anatolian Fault, pass through the country. In the last century, Turkey endured 111 earthquakes with a magnitude of 5 or more, and 55 earthquakes of a magnitude greater than 6.8 occurred between 1932 and 1999 . The 199The first national seismic design code was published in 1944 after the 1939 Erzincan Earthquake (M 7.9), and the 1998 version can be considered the first modern seismic code. The Construction Inspection Law passed in 2001 led to better quality control of construction. Therefore, buildings constructed before 1980 are most vulnerable and need to be seismically upgraded, buildings constructed between 1980 and 2000 have a low risk of collapse during earthquakes, and buildings constructed after 2000 are considered to have sufficient earthquake-resistant capacities . It was 2.7.1.Until the 2011 Van Earthquake, Turkey’s seismic policy for existing buildings relied on post-earthquake recovery insurance and thus was largely reactive. The National Earthquake Insurance Program, established after the 1999 Kocaeli Earthquake, built a two-level earthquake insurance system to transfer risks via financial methods. Level one is the national compulsory earthquake insurance, called Turkish Catastrophe Insurance Pool (TCIP) and developed under the guidance of the World Bank to addresses structural damages. Level two is a private homeowner’s earthquake insurance, which covers structural, non-structural, and business interruption losses that exceed the TCIP’s limit. The premiums of the two levels of insurance are fixed by the government, and all companies in the market with a valid license are allowed to sell TCIP and private homeowners’ insurances . The covAfter the 2011 Van Earthquake, the Turkish Parliament adopted the Urban Transformation Law, which required the Ministry of Environment and Urbanization (MEU) to identify and retrofit hazardous buildings in high-seismicity regions. The law established technical standards and procedures for seismic assessment, retrofit, and reconstruction of existing buildings, based on EN1998–3. Local technical commissions were formed, comprising ministry employees and professors in colleges, to evaluate and determine whether a building is hazardous.2.7.2.In 2005, Turkey initiated the Istanbul Seismic Risk Mitigation and Emergency Preparedness Project (ISMEP), intended to enhance emergency preparedness, enforce building codes, and to mitigate seismic risks for critical public facilities. This project was funded by loans provided by several international funding institutions . About 2Turkey’s Urban Transformation initiative is partially funded by the European Investment Bank. According to official estimates, about 9 million buildings have insufficient seismic resistance capacities, which constitutes one third of the entire building block in Turkey. Retrofitting or reconstructing those buildings would cost $500 billion and need at least 20 years . For bui2.8.Romania is periodically subject to strong earthquakes. The 1940 Vrancea Earthquake (M 7.7) caused considerable damage to masonry buildings in the southeast of the country. The tallest reinforced concrete building  in the City of Bucharest collapsed entirely. After the earthquake, Romania adopted a tentative earthquake-resistant design code. The code was enacted in 1942, but the design code was not endorsed as a mandatory regulation until 1963 .The 1977 Vrancea Earthquake (M 7.4) led to the collapse of 28 high-rise buildings that were slightly damaged in the 1940 earthquake. In addition, 156,000 apartments in urban areas and 21,500 buildings in rural areas were severely damaged or collapsed, and 366,000 urban apartments and 117,000 rural houses had to be repaired. About 1,578 people died, and more than 11,300 people were injured. After the earthquake, Romania updated the seismic zonation map to raise the seismic-resistant level of new construction  and intr2.8.1.Romania planned to strengthen 122 buildings designated as the most vulnerable structures in Bucharest  following the 1977 earthquake. However, due to lack of experience in seismic retrofit, the Romanian government requested technical assistance from Japan in 1978, aiming to transfer Japanese seismic technology to its country .R (a parameter for a building’s ability to dissipate energy) to assist decision making for rehabilitation. In the mid-1990s, Romania started to incorporate European regulations into its building code. The 2008 Romanian Code for seismic assessment and retrofitting of existing buildings included the notions and concepts of European Standard EN 1998–3. The code also preserved the quantitative assessment approach based on the seismic safety factor and a three-tier approach, which is similar to that of the ASCE 31–02 standard, formerly FEMA-310.Following the 1986 and 1990 Vrancea Earthquakes (M 7.1 and M 6.9), the 1992 Romanian Building Code introduced a quantitative assessment approach, based on the seismic safety factor 2.8.2.In 1992, the Romanian government initiated a National Seismic Assessment and Rehabilitation Program for existing buildings. The government fully funded seismic assessment and regularly published the list of assessed buildings and their risk classes. For buildings identified to be at risk, owners were responsible for retrofit cost. The government offered a low-interest loan to motivate building owners to strengthen their buildings . By 20132.9.India is prone to devastating earthquakes caused by the collision of the Indian Plate and the Eurasian Plate, which has formed the Himalaya Mountains. Seven earthquakes between 1988 and 2005 of M 6.0 or greater claimed more than 25,000 lives and rendered approximately a million houses uninhabitable in India. Over 95% of the fatalities were found in non-engineered houses, which were constructed in a traditional manner without the design of qualified architects and engineers .India published the first seismic code (IS 1893) in 1962, which was not mandatory until 2001. In 1991, the code was split to address four structural groups . Two new codes for non-engineered construction (IS 13827 and IS 13828) were published in 1993, providing seismic provisions for earthen buildings and low-strength masonry buildings, respectively. The two codes were intended to improve the seismic performance of non-engineered structures rather than to stop the construction of such buildings .About 95% of buildings in India are made of mud, stone, bricks, timber, and bamboo, while concrete or steel structures constitute 3.6% of entire building stock . ReinforA national Earthquake Engineering Training program was implemented during 2003–2007 by the Indian Institutes of Technology and the Indian Institute of Science, with financial support from the government. The program offered training to more than a thousand teachers in Civil Engineering and Architecture colleges, which enabled the concepts and techniques of seismic engineering to be taught in the classroom .2.9.1.The code for seismic evaluation and strengthening of existing buildings (IS 15988) was published in 2013. In 2014, the Indian government published the National Disaster Management Guidelines on Seismic Retrofitting of Deficient Buildings and Structures, which recommended making seismic retrofit mandatory for existing government-owned buildings and privately-owned buildings that are critical to industrial and commercial activities, safety and security, health care, and education. The guidelines also encouraged the retrofit of (1) buildings located in high-risk seismic zones, (2) unreinforced masonry buildings and reinforced concrete buildings with open ground floors or soft stories, and (3) buildings not designed by appropriately credentialed engineers or constructed based on improper designs. Moreover, a cost-based decision-making method was provided for building owners to determine whether to retrofit or reconstruct their buildings, as described in 2.9.2.The 2.10.Nepal lies on two active tectonic plates, the Indian Plate and the Tibetan Plate, which have produced frequent, devastating earthquakes. The 1988 Nepal Earthquake (M 6.9) killed 721 people and destroyed more than 7,000 buildings. The 2015 Nepal Earthquake (M 7.8) caused the collapse of 500,000 residential buildings and 2,656 office buildings, with an additional 200,000 residential buildings and 3,622 office buildings damaged. An estimated 8,790 people died and 22,300 people were injured .The National Building Code was adopted in 2003, providing the first seismic design standard for new buildings in Nepal. However, the code was not enforced effectively because monitoring the implementation of the regulation proved challenging. Some municipalities around Kathmandu Valley, the most developed and populated region in Nepal, allowed voluntary compliance with the code . In geneOver the last two decades, the United Nations Development Programme (UNDP) assisted the Government of Nepal in preparing the National Building Code, developing curricula and manuals for engineers and masons to properly implement the Building Code, and establishing code-compliant building permit systems in several municipalities. In 2011, the UNDP launched the Comprehensive Disaster Risk Management Programme (CDRMP) to improve resilience and strengthen the institutional and legislative sectors of Nepal for disaster risk management. This involves building the capacity of government ministers, departments and agencies, and local governments, and strengthening the partnership between governments and private sectors .2.10.1.After the 2011 Sikkim Earthquake (M 6.9), the UNDP, in collaboration with Nepal’s Department of Urban Development and Building Construction and Center of Resilient Development, developed the first seismic retrofit guidelines for three dominant building categories: adobe, masonry, and reinforced concrete structures. After the 2015 Nepal Earthquake (M 7.8), the Government of Nepal realized the importance and urgency of strengthening existing buildings and adopted the seismic retrofit guidelines . The gui2.10.2.Nepal’s National Society for Earthquake Technology (NSET), with the support of the Asian Development Bank (ADB), developed a five-year plan to strengthen 900 schools in the Kathmandu Valley at an estimated cost of $30 million. Funding was provided by the national and local governments, the ADB, Aus Aid, the government of Japan, and the World Bank . In addi3.The key takeaway that emerges is that adoption of retrofit policies has historically been driven by earthquake impacts. Major earthquakes have been followed by significant policy changes that seek to protect life and property. Countries in this study have recently experienced, or continue to experience, destructive earthquake events while the United States has not endured one since Northridge in 1994.National, state, and local governments need not to wait for another catastrophe to mitigate risk from seismic impacts. Engineering and implementation knowledge necessary for effective retrofit interventions is available and can prevent many deaths and injuries in inevitable future earthquake events. For example, from Japan comes the knowledge that rigorous monitoring and regular policy updates are essential. Japan not only amends building regulations after an earthquake to prevent structural defects in new construction, but also conducts periodic surveys such as the Housing and Land Survey to formulate housing-related policies to enhance seismic resilience. The government also adjusts incentive policies to close a critical gap between planned and actual rates of retrofit .Design standards and retrofit policies are adopted at the local level in the United States, which is very different from procedures in other countries. Nevertheless, lessons from other countries may prove useful to state and local governments attempting to enhance seismic resilience in the United States, as well as governments in any earthquake-prone country. Based on the lessons learned from the preceding comparative study of seismic retrofit policies, recommendations are organized around key stages of the seismic retrofit process. It is important to note that this process should not be seen as one-time or linear, but instead should be part of a recurring cycle, from risk assessment through monitoring, to continue improving the seismic resilience of the building stock. In this way, governments can continue to find appropriate solutions that will help prevent deaths, injuries, destruction, and downtime.3.1.The first step in designing a retrofit policy is to identify the problem. Thus, seismic evaluation of buildings is seen to be an integral component of retrofit policies around the world. The lessons learned suggest the following best practices for assessing risk.Support for seismic evaluation: Japan’s Seismic Retrofitting Promotion Laws and Romania’s National Seismic Assessment and Rehabilitation Program provide generous subsidies to building owners for seismic evaluation, which is less expensive and thus easier for local governments to partially or fully fund than the retrofit itself . In addiPublic results: Information about the potential risk posed by buildings should be available and accessible to the community, as in Japan and Romania. In the U.S., cities and counties in California with retrofit mandates identified properties that must be retrofitted and made lists publicly available so that building users and community members were informed about high-risk buildings in their community. In addition, data repositories should have procedures to record updated information regarding retrofit or reconstruction.Communicate results: It is imperative to explain risk from seismic events to non-technical audiences in a clear and simple way. Currently, the U.S. does not use a comprehensive mechanism to communicate to the public, even implicitly, a building’s anticipated performance or risk level in an earthquake event. Italy uses the seismic class to describe the risk level of a building . New ZeaInvisible risk: Buildings that have undergone some level of shaking should be evaluated even if no damage is apparent. A building that survives an earthquake could still result in substantial losses in a subsequent event. In Romania, buildings that survived an earthquake with only slight damage collapsed 37 years later in another earthquake .3.2.Decision-support tools: Communities and building owners can make informed decisions with the right tools. For example, India , Japan , and NewPublic-private partnerships: Partnerships with the private sector and academia can be invaluable for expanding the local knowledge base, educating the public, and increasing technical training. In Turkey, seismic evaluation procedures under the Urban Transformation Law were developed and conducted collaboratively between ministry employees and scholars in the field . Such paLocal knowledge: No one understands the risk to a community better than the community itself. In Italy, the Civil Protection Department educates the public on seismic, flood, and landslide risk during public awareness days called “I do not risk” . MoreoveFederal guidelines and provisions, together with the national model building code, often provide the foundation for local retrofit policy in the United States. Nevertheless, state and local governments may benefit from technical knowledge and support from experts in the field. In addition, information sharing regionally, nationally, and internationally is an important mechanism by which the field of earthquake risk mitigation evolves. The following best practices are identified:3.3.Traditionally, the most vulnerable buildings have been prioritized and selected based on construction type; for example, unreinforced masonry buildings are well documented as some of the most vulnerable . Beyond Prioritize building use: In addition to targeting vulnerable buildings by construction type, policies can target building use. For instance, China’s National Plan for Earthquake Hazards Reduction, Iran’s Doable Initiative, and Japan’s Seismic Retrofitting Promotion Law target “critical” buildings such as hospitals and schools through either mandatory retrofits or incentives. It is also important for recovery, a primary motivation for the mandated retrofit of hospitals in California .Prioritize public buildings: Another important category that is often targeted by retrofit policies is that of government buildings . In the U.S., Presidential Executive Order (EO 13717) recommends that federal buildings be retrofitted to improve the seismic resilience of the nation, while San Francisco retrofitted over 100 of its public buildings.3.4.Financial support: It is difficult to monitor and enforce retrofit standards on residential properties. Several countries thus offer financial support for voluntary residential retrofits, such as Japan’s system of subsidies  and ItalNormalize retrofit procedures: Part of the reason that retrofit is so costly is because it is unique to each building. In China, buildings are retrofitted based on government plans and budgets, which saves building owners time and money in submitting retrofit plans and applying for building permits . SimilarTriggers: a seismic retrofit can be conducted as a standalone process. However, it may be more effective when coupled with another activity already taking place and can therefore be administratively folded into existing work. New Zealand’s Building Act 2014 stipulates that structural alteration to a building’s function, including expanding rooms or adding new rooms, triggers a seismic retrofit. Similarly, in the U.S., alterations, additions, change of occupancy, and change of use may trigger a retrofit . One wayIntegration with other objectives: Countries such as China  and ItalPerhaps the most challenging stage of the retrofit process is making sure a retrofit happens. Even under retrofit mandates, compliance is not always ensured. However, financial support has been shown to increase compliance rates. Another route to compliance is to bundle seismic retrofit with other upgrades for which a building owner is willing to pay. In many countries, including the U.S., buildings that sustain damage in an earthquake, as well as buildings that are being renovated, can trigger a mandatory retrofit. An extension of this idea leverages interest in sustainable infrastructure by pairing energy-efficiency upgrades with seismic retrofit. The lessons suggest the best practices for implementation of retrofit policy:3.5.Monitoring and evaluation: Risk mitigation is not a one-time process. Regular monitoring and evaluation are necessary to ground-truth retrofit efforts. In addition to the collection of information at the time of retrofit construction application or completion, there are other methods by which to gather relevant information. For example, Japan conducts regular surveys to collect information on structures, assess impacts and deficiencies, and help to inform policy updates . EnsurinHolistic perspective: Retrofit of individual building assets is incredibly important, particularly for building occupants, users, residents, or owners. However, building failure and collapse can have significant consequences not only for individuals associated with that building, but for those nearby, in addition to other cumulative consequences of building failure across the area, city, or region. Any jurisdiction looking to mitigate risk may want to consider what geographic or demographic areas of the city or region should be targeted for retrofit activities in order to ensure the best post-earthquake outcomes. Japan’s 2005 Seismic Retrofitting Promotion Law designated emergency routes and evacuation facilities specific to the earthquake hazard. These routes and infrastructure would have retrofit actions considered to ensure their usability. In Turkey, some buildings are considered to be so risky to the population that they are mandated for demolition, with the government providing rent assistance to displaced residents . The U.SAssuring recovery: Knowing that retrofit policies take time to yield results, and that some kinds of buildings may not be suitable for retrofit, policy makers may also consider the utility of earthquake insurance. In the event of an earthquake, insurance can enable repairs or reconstruction, and help ensure community continuity that could be in danger following a large-scale earthquake with regional impacts. Turkey offers compulsory earthquake insurance for residential buildings, the Turkish Catastrophe Insurance Pool (TCIP). While this kind of requirement may not be appropriate in all areas of the U.S., for those places with significant risk, or with significant risk particularly from older buildings, mandatory earthquake insurance may provide some protection to communities and building owners in cases where retrofits cannot reasonably be applied, or older buildings are able to avoid retrofit triggers.Once a retrofit policy is in place, it is important to ensure that policies and activities are having their intended effect. Is seismic risk reduced? Can we reasonably assume that deaths, injuries, or downtime have been reduced? Policy development alone is insufficient to ensure impact. The lessons learned from other countries suggest that continuous monitoring and updating is a best practice:4.In countries that have proactive retrofit policies in place, including Japan, Italy, and New Zealand, the number of collapses and severely damaged buildings in recent earthquakes is lower than would have been expected. This suggests that improved seismic design, including retrofits, can have a meaningful impact on building performance during an earthquake event. The lessons learned suggest several recommendations for state and local governments designing seismic retrofit policy to improve their seismic resilience. The recommendations are organized around key stages of the retrofit process, with the understanding that risk mitigation planning is a nonlinear and recurring process. While the experiences of other countries with retrofit policy are instructive for the United States, several gaps remain.Across the countries in the study, retrofit policies have largely targeted the most vulnerable buildings: masonry and adobe, older concrete, and wood-frame buildings, depending on their prevalence. Beyond addressing the most vulnerable buildings, retrofit policies tend to focus on “critical” buildings for which failure would pose significant risk to public safety. The question of how to prioritize buildings is highly context-specific to each country. There seems to be consensus around schools and hospitals, but some countries may consider buildings that host large numbers of people, such as high-rise office buildings, department stores, and hotels in Japan, while others may consider critical infrastructure, such as nuclear facilities in Iran. A potential direction for future research is to investigate and identify parameters for the spectrum of retrofit interventions, from minimum standards (focusing on those buildings posing the greatest risk) to the maximum application (going beyond which will provide little return or benefit).Questions also remain about how to ensure compliance, especially under voluntary policies. Even under mandatory policies, compliance is not always 100%. Another obstacle is that not enough is known about retrofit cost, which tends to be variable across countries, and therefore, designing appropriate incentives is challenging. For the U.S., methods exist for estimating structural retrofit cost e.g., , but theFinally, timing is an important concern. Several cities in the U.S. have set compliance timelines only to revise them due to low rates of compliance. Countries such as Japan continually update their targets by collecting data. The tradeoff between providing sufficient time for compliance and ensuring sufficient compliance rates has not been investigated in the literature.


Necator and Oesophagostomum were the most prevalent genera, and we commonly observed mixed infections of more than one strongylid species. Human strongylid communities were dominated by the human hookworm N. americanus, while great apes were mainly infected with N. gorillae, O. stephanostomum and trichostrongylids. We were also able to detect rare strongylid taxa (such as Ancylostoma and Ternidens). We detected eight ASVs shared between humans and great apes . Our results show that knowledge of strongylid communities in primates, including humans, is still limited. Sharing the same habitat, especially outside protected areas (where access to the forest is not restricted), can enable mutual parasite exchange and can even override host phylogeny or conserved patterns. Such studies are critical for assessing the threats posed to all hosts by increasing human-wildlife spatial overlap. In this study, the term "contact" refers to physical contact, while "spatial overlap" refers to environmental contact.Rapid increases in human populations and environmental changes of past decades have led to changes in rates of contact and spatial overlap with wildlife. Together with other historical, social and environmental processes, this has significantly contributed to pathogen transmission in both directions, especially between humans and non-human primates, whose close phylogenetic relationship facilitates cross-infections. Using high-throughput amplicon sequencing, we studied strongylid communities in sympatric western lowland gorillas, central chimpanzees and humans co-occurring in an unprotected area in the northern periphery of the Dja Faunal Reserve, Cameroon. At the genus level, we classified 65 strongylid ITS-2 amplicon sequencing variants (ASVs) in humans and great apes. Great apes exhibited higher strongylid diversity than humans.  Strongylid nematodes are common intestinal parasites, infecting a wide range of mammalian taxa, including humans and non-human primates (NHPs). They have evolved to live in vertebrate hosts for months or years and form complex communities within these hosts. Heavy strongylid infections can cause severe intestinal inflammation, intestinal lesions, respiratory difficulties, iron deficiency anemia, weight loss, childhood stunting, and adverse birth outcomes. As human population and human settlements have grown rapidly in recent decades, people often live in close proximity to wildlife, allowing for cross-transmission of soil-transmitted helminths. Because humans and NHPs  are closely related to one another evolutionarily, it is easy for strongylids infecting one primate species to jump to a different primate host. This evolutionary relationship can result in overlap and reciprocal exchange of pathogens and can have a damaging effect both on humans and NHP endangered species populations. As DNA-based diagnosis has become a routine part of modern parasitology, we employed a modern high-throughput sequencing approach to describe complex communities and zoonotic patterns of parasitic strongylid nematodes infecting humans and great apes in Cameroon. Necator americanus, Ancylostoma duodenale, and A. ceylanicum), infecting over 400 million people worldwide [Necator hookworms and the nodule worm of the genus Oesophagostomum are considered the most prevalent helminths in great apes [Among parasites, strongylid nematodes are of high importance to research, because they cause one of the most common but neglected tropical diseases in humans associated with the occurrence of pathologies ,2. They orldwide . Necatoreat apes .Unfortunately, identification of distinct strongylid taxa from feces using microscopy is essentially impossible, as strongylid eggs are morphologically indistinguishable . Thus, sOesophagostomum species were found to be shared between humans and great apes in Eastern Africa [Necator species are shared in Central African Republic and Gabon [Necator spp. as a main driving force of overlap between different hosts.The close phylogenetic relationship between NHPs and humans significantly facilitates the overlap and transmission of pathogens and can have a damaging effect on populations of both humans and endangered NHPs ,26. The n Africa ,32 and and Gabon ,34. UsinWe explored strongylid nematode diversity in humans and great apes cohabiting an unprotected area in the northern periphery of the Dja Faunal Reserve, Cameroon. We evaluated possible zoonotic transmission patterns and assessed the impact of behavioral/hygiene habits of the local people on their strongylid infections. We employed an ITS-2 metabarcoding approach and predicted differences in strongylid nematode communities between different primate hosts.The research complied with the legal requirements of the Cameroon and was approved by Ministère de la Recherche Scientifique et de l’Innovation (permit number 0000105/MINRESI/B00/C00/C10/C12) and Ministère des Forêts et de la Faune (permit number 1371/PRS/MINFOF/SG/DFAP/SDVEF/SC). The ape samples were collected noninvasively and did not affect the animals. Human sampling and data collection followed the protocol approved by the Ethics Committee of the Biological Centre of Academy of Sciences, České Budějovice, Czech Republic and was approved by the local authorities. Sampling was performed after obtaining oral and written informed consent of all registered volunteers. Samples were numbered, paired with questionnaires and anonymized.2), comprising the target area of Project Grands Singes (PGS), under Antwerp Zoo Society, Belgium included the research camp La Belgique and three village settlements approximately 25 km from the camp. Several ethnic groups  live in the periphery of the reserve in close coexistence with wildlife [Pan troglodytes troglodytes) and western lowland gorillas (Gorilla gorilla gorilla) were recorded in the reserve as well as in the unprotected area around the camp La Belgique [Our study took place in the northern periphery of the Dja Faunal Reserve (Dja FR), located in South-East Cameroon. The reserve is part of a semi-deciduous lowland forest (500–700 m above sea level) with an equatorial and humid climate characterized by one short and one long dry season in between two rainy seasons (February–July/August–November) . The unpwildlife . Althougwildlife , huntingwildlife ,39 and lwildlife  remain tBelgique .n = 139) were collected non-invasively from humans (n = 48), median age 26 years, and free-ranging great apes: central chimpanzees (n = 31) and western lowland gorillas (n = 60). Human participants were provided with sampling tubes and samples were then gathered by researchers in the villages. Samples of great apes were collected from the ground under morning nests, a maximum of three hours after individuals left their nests. To reduce the risk of re-sampling of the same individuals and groups of individuals, only groups of different sizes  or groups of the same size  were sampled, and one sample per nest was taken. The samples were immediately fixed in 96% ethanol and stored at room temperature for a maximum of two weeks until they were sent to the Department of Pathology and Parasitology of University of Veterinary Sciences Brno, where they were stored at -20°C.Human sampling was carried out in three villages–Duomo-Pierre, Malen V, and Mimpala –and great ape samples were collected in secondary forest areas between the villages and around La Belgique research camp during September and October 2014 (major wet season peak). Fresh fecal samples  and amplified ribosomal DNA (rDNA), specifically the variable section of rDNA . We prepared sequencing libraries according to the protocol of Pafčo et al. , using tth February 2020); we excluded environmental or uncultured samples from the database and filtered out all blast hits with < 85% identity and < 90% coverage from the file. We downloaded taxonomy for blast hits using taxize package [We trimmed raw.fastq sequences using Skewer  and foll package , and use package .https://www.rstudio.com); into a single phyloseq object, suitable for downstream analyses. We executed all data analyses in the statistical software RStudio. We de-noised the raw dataset (variants unclassified up to “family” level and “non-strongylid” were removed from the dataset) and used a generalized linear model (GLM) with quasipoisson error distribution to test differences in alpha diversity, evaluated as number of ASVs per sample, among the studied hosts. Additionally, we employed post-hoc testing (Tukey) to identify levels of factorial response that differ from each other. Moreover, we measured the alpha diversity by Shannon’s and Simpson’s indexes; we defined community composition as prevalence and relative representation of ITS-2 ASVs using Jaccard and Bray-Curtis ecological distances. In order to prevent negative eigenvalues during computation, we performed square root transformation of the dataset. We then performed Principal coordinate analysis (PCoA) on both Jaccard and Bray-Curtis dissimilarities. To test the interspecific differences in strongylid nematode community compositions among the hosts, we executed permutational analysis of variance (PERMANOVA), followed by analysis of similarity (ANOSIM). We implemented Multivariate general linear models (GLMs) from the R package mvabund [We merged the resulting taxonomy table with our metadata table in RStudio ( mvabund  to searcn = 48), western lowland gorillas (n = 60) and central chimpanzees (n = 31). In total, 2,943,087 high-quality reads were identified, with a median sequencing depth per sample of 15,612 . After duplication of the obtained sequencing data from negative control samples, no ITS-2 strongylid reads were found. Taxonomic assignment revealed 65 ITS-2 amplicon sequencing variants (ASVs), including at least five strongylid genera , thus those variants probably do not represent these genera and could possibly indicate novel nematode species in the sample.We analyzed fecal samples of humans , while N. gorillae variants were less common . A significant portion of human infections also included O. stephanostomum type I . Trichostrongylus sp. type II  and four unassigned variants  were also found in humans. Strongylids in great apes were dominated by variants of N. gorillae , Oesophagostomum stephanostomum type I , Trichostrongylus sp. type II  and unassigned variants . Necator americanus variants were found only in gorillas , while there was no evidence for N. americanus in chimpanzees. Additionally, unidentified variants of Necator species (neither N. americanus nor N. gorillae) were detected in great apes . Three taxa were recorded in low prevalence and with reads only evident in gorillas  and one taxon was detected only in a chimpanzee (Ancylostoma sp. 228 reads). We found eight ASVs shared between humans and great apes , suggesting zoonotic transmission: two N. gorillae variants, one O. stephanostomum type I variant, and one Trichostrongylus sp. type II variant were found in humans, gorilla and chimpanzees, while four N. americanus variants were shared only between humans and gorillas.The most prevalent variants belonged to three genera: rongylus . A bar grongylus . Humans x′ = 7; min. = 1, max. = 17) differed among the studied hosts  = 203.36, p < 0.0001). Variant diversity in humans was lower compared to both species of great apes   = 11.655, p = 0.001; Bray-Curtis: F = 14.644, p = 0.001) and ANOSIM  tests. Tukey post-hoc testing revealed significant differences between humans and other great apes for both Jaccard and Bray-Curtis  distances. Within great apes, there was no statistically significant result for Jaccard (p = 0.36) indicating roughly the same composition of strongylid ASVs; however, results for Bray-Curtis indicated differences in relative abundances (proportion) of ASVs between great apes (p < 0.001). Mvabund testing confirmed the interspecific differences  and identified 17 ITS-2 ASVs with whose different relative abundances were the main driving force of diversity between different host species in contrast to shared haplotypes  , while tarisons) . Signifiplotypes . DiffereWe found no significant impact of behavioral or hygiene habits of the local people on either strongylid alpha or strongylid beta diversity .We explored strongylid diversity and transmission patterns in humans and great apes sharing the same habitat in an unprotected area at the northern border of the Dja Faunal Reserve (Dja FR), Cameroon. Using the ITS-2 locus for identification, general taxonomic assignment revealed 95 strongylid ITS-2 amplicon sequence variants (ASVs), of which we could classify 65 at the genus/species level. We are aware of the limitations of the ITS-2 marker –19 and aIn contrast to our previous study in Dzanga Sangha Protected Areas (DSPA), Central African Republic, where only two variants  remained unassigned , our datNecator and Oesophagostomum are the most prevalent strongylid genera in African apes and humans [Trichostrongylus and unassigned genera. Dja apes were mostly infected by variants of O. stephanostomum and N. gorillae, both commonly found in great apes [N. americanus variants, confirming that N. americanus is the dominant human-specific hookworm in general [Entamoeba (protozoan parasite) communities in people living in the Dja compared to co-occurring great apes.Overall, the composition of strongylid communities found in Dja remained generally consistent with previous studies, suggesting that d humans ,34,49,50eat apes ,24,32,50 general . Great a general  used theMason et al.  employedNecator spp.  being shared between multiple hosts. Besides the human hookworm N. americanus, other Necator species  have been reported in great apes [N. americanus and two variants of N. gorillae were found co-infecting humans and great apes, suggesting ongoing transmission events previously described in the tropical forest ecosystem in DSPA and Moukalaba-Doudou National Park [N. americanus variants were found mostly in humans, four of them were shared with gorillas; this demonstrates that N. americanus is not a solely human-specific parasite. Moreover, such a finding was previously observed in African great apes [Necator gorillae variants were found predominantly in great apes, suggesting its probable ape origin, but they were also shared with humans. The N. gorillae variants corresponded to those previously found in gorillas in Gabon [N. americanus infecting wild chimpanzees, which supports a previous hypothesis of a lower susceptibility of chimpanzees to N. americanus infections [Necator sp. in Dja apes corresponding to variant III-1 first found in humans in DSPA by Hasegawa et al. [N. congolensis or N. exilidens, previously described in chimpanzees [N. congolensis or N. exilidens were made at the beginning of the last century, and even “traditional” morphology-based taxonomy of Necator non-americanus species remain unclear [Necator species are clearly capable of infecting both humans and NHPs, at least in habitats where they share the same environment. However, the exact species diversity is not known, nor is the epidemiology and ability (particularly of the non-americanus species) to spread in human populations. Therefore, large-scale studies covering multiple populations of wild great apes, other NHPs and humans, with utilization of advanced HTS tools combined with modern morphological characterizations will be required for better understanding of Necator epidemiology.We discovered six ASVs of eat apes –58 and aeat apes ,33,59. Fnal Park ,16,33,34eat apes ,33,34. Nfections . Additioa et al. ,34. Hasempanzees ,57; howeOesophagostomum species are commonly found in great apes and humans throughout Africa–O. stephanostomum [O. bifurcum in humans, especially in West Africa [Oesophagostomum species have been recorded, but they are much rarer [O. stephanostomum type I shared among great apes and humans in Dja, corresponding to the variant infecting NHPs and humans in Kibale, Uganda [O. stephanostomum in humans, providing evidence that Oesophagostomum species have zoonotic potential under suitable circumstances. Pafčo et al. [O. stephanostomum infecting NHPs in DSPA but not in humans, thus suggesting its ape origin. This is also supported by Mason et al. [O. stephanostomum in high prevalence in western lowland gorillas across several African localities. We only found the second Oesophagostomum group (Oesophagostomum stephanostomum type II) in great apes; this group was previously described in western lowland gorillas in Moukalaba-Doudau National Park (MDNP), Gabon [Oesophagostomum sp. in one gorilla. They correspond to Oesophagostomum sequences from humans and NHPs in Kibale, Uganda [O. bifurcum infecting mangabeys in DSPA, but not great apes; we also found no evidence of this species in great apes or humans in Dja FR, although it is known to commonly infect both humans and NHPs in Africa [Two nostomum ,50 in grt Africa ; other Och rarer ,13. We r, Uganda . This meo et al.  also repn et al. , who fou), Gabon  and in D), Gabon ). We onl, Uganda , further, Uganda  in olive, Uganda , found On Africa ,61,63.Ternidens deminutus, the cyathostomine worm Murshidia spp. [Mammomonogamus [Trichostrongylus spp. being harbored by Dja FR great apes (their strongest BlastN matches were to trichostrongylids parasitic in sheep), and we found one variant to be shared between great apes and one human at Dja FR, corresponding to the Trichostrongylus variant from chimpanzees living in degraded forest fragments in Bulindi, Uganda [Trichostrongylus were reported by Pafčo et al. [Trichostrongylus worms were found in necropsied mountain gorillas in Rwanda [Trichostrongylus infections have been reported in humans in north-eastern Thailand, Lao People’s Democratic Republic (PDR) and urban areas of Salvador City, Brazil [Trichostrongylus infections are considered rather incidental. We found one variant of Ternidens deminutus infecting western lowland gorillas, closely similar to the one from Mona monkeys (Cercopithecus mona) found in Ghana [T. deminutus variants infecting great apes, being closely related to the same sequence. T. deminutus is considered to be a neglected parasite of humans [Ancylostoma duodenale is considered a human-specific parasite and was found by Pafčo et al. [Ancylostoma sp. ever recorded; however, we could not specifically assign the variant to a known Ancylostoma species, and it was found in only one chimpanzee sample, representing 100% of total sample reads. Such homogeneity in chimpanzees is rather unusual, according to our dataset.Other strongylid nematodes also infect humans and NHPs in Africa, such as the “false hookworm” dia spp. , strongydia spp. ,65, and onogamus . We foun, Uganda . Varianto et al.  and Masoo et al.  in lowlan Rwanda . Althoug, Brazil ,69, humain Ghana ; this fiin Ghana , who fouf humans  and has f humans , thus rao et al.  in humanN. americanus variants in both prevalence and relative abundance (measured as the proportion of sequencing reads assigned to this species). On the other hand, the strongylid communities of the two great ape species overlapped and were dominated by variants belonging to N. gorillae, O. stephanostomum, Trichostrongylus type II and unclassified variants. Our results corroborate those from DSPA, CAR [Entamoeba communities in Dja FR overlapped, while that of gorillas formed a clearly separated cluster, displaying a pattern that reflects the phylogenetic distance between the hosts [In Dja FR, humans exhibited lower strongylid alpha diversity than great apes and formed a separate cluster distinct from great apes, which was caused by dominance of SPA, CAR , where tSPA, CAR , thus haSPA, CAR . Intereshe hosts . Mann ethe hosts  analyzedhe hosts , these rhe hosts . More stNecator, Oesophagostomum and Trichostrongylus are parasites transmitted by skin penetration or oral ingestion [In Dja FR, we found no impact of frequency of entering the forest, interaction with great apes, clothing, hygiene, anthelmintic treatment or dietary habits; however, the implementation of questionnaires was a pilot activity, and a more detailed and rigorous social science approach would be needed to explain differences in strongylid infections among Dja FR humans. We recorded higher numbers of strongylid ASVs shared between humans and great apes in Dja FR in comparison to DSPA. This is quite surprising as the majority of human respondents in Dja FR were agriculturists while in DSPA the studied humans were contemporary BaAka hunter-gatherers and some were even employed as gorilla trackers for the Primate Habituation Programme ,73. Our ngestion . People Future research should include analyses of the strongylid communities of apes from multiple areas of varying conservation status. For example, it is necessary to sample gorillas from the special reserve in DSPA, multiple-use zone with human activities surrounding the national park and Bantu people following agricultural lifestyle co-habiting DSPA, to better understand the drivers of transmission patterns in various host cohorts ,77. ImpoOesophagostomum and Necator were the dominant components of strongylid communities in all studied hosts, and the driving force of strongylid overlaps. Human communities were dominated by Necator americanus; although generally thought to be human-specific, this parasite was also shared by gorillas. Necator gorillae, originally thought to be a parasite confined to NHPs, was widespread across all studied host species, including humans. We observed a second case of O. stephanostomum infection in humans. In contrast to previous studies conducted in the DSPA, CAR, we recorded more genera and variants being shared between humans and great apes, which might be due to significant anthropogenic pressure in the periphery of the reserve, which is not protected. Most African apes occur outside protected areas [We reveal complex strongylid nematode communities of great apes and humans sharing an unprotected tropical forest habitat in Cameroon. The great apes exhibited a greater diversity of the strongylid fauna harbouring more amplicon sequencing variants (ASVs) and rare variants in comparison to humans. ed areas  and thusS1 FigAll participants spoke French and researchers assisted them to fill in the questionnaires.(JPG)Click here for additional data file.S1 Table(XLSX)Click here for additional data file.