It is difficult to diagnose<unk>  virus infection based on clinical signs and symptoms alone due to overlaps with other arboviruses that are endemic to similar areas. The US Centers for Disease Control and Prevention (CDC) advises that "based on the typical clinical features, the differential diagnosis for<unk>  virus infection is broad. In addition to dengue, other considerations include leptospirosis, malaria, rickettsia, group A streptococcus, rubella, measles, and parvovirus, enterovirus, adenovirus, and alphavirus infections (e.g., chikungunya, Mayaro, Ross River, Barmah Forest, O'nyong'nyong, and Sindbis viruses)." In small case series, routine chemistry and complete blood counts have been normal in most patients. A few have been reported to have mild leukopenia, thrombocytopenia, and elevated liver transaminases.<unk>  virus can be identified by reverse transcriptase PCR (RT-PCR) in acutely ill patients. However, the period of viremia can be short and the World Health Organization (WHO) recommends RT-PCR testing be done on serum collected within 1 to 3 days of symptom onset or on saliva samples collected during the first 3 to 5 days. When evaluating paired samples,<unk>  virus was detected more frequently in saliva than serum. Urine samples can be collected and tested up to 14 days after the onset of symptoms, as the virus has been seen to survive longer in the urine than either saliva or serum. The longest period of detectable virus has been 11 days and<unk>  virus does not appear to establish latency. Later on, serology for the detection of specific IgM and IgG antibodies to<unk>  virus can be used. IgM antibodies can be detectable within 3 days of the onset of illness. Serological cross-reactions with closely related flaviviruses such as dengue and West Nile virus as well as vaccines to flaviviruses are possible. As of 2019, the FDA has authorized two tests to detect<unk>  virus antibodies. Screening in pregnancy The CDC recommends screening some pregnant women even if they do not have symptoms of infection. Pregnant women who have traveled to affected areas should be tested between two and twelve weeks after their return from travel. Due to the difficulties with ordering and interpreting tests for<unk>  virus, the CDC also recommends that healthcare providers contact their local health department for assistance. For women living in affected areas, the CDC has recommended testing at the first prenatal visit with a doctor as well as in the mid-second trimester, though this may be adjusted based on local resources and the local burden of<unk>  virus. Additional testing should be done if there are any signs of<unk>  virus disease. Women with positive test results for<unk>  virus infection should have their fetus monitored by ultrasound every three to four weeks to monitor fetal anatomy and growth. Infant testing For infants with suspected congenital<unk>  virus disease, the CDC recommends testing with both serologic and molecular assays such as RT-PCR, IgM ELISA and plaque reduction neutralization test (PRNT). RT-PCR of the infants serum and urine should be performed in the first two days of life. Newborns with a mother who was potentially exposed and who have positive blood tests, microcephaly or intracranial calcifications should have further testing including a thorough physical investigation for neurologic abnormalities, dysmorphic features, splenomegaly, hepatomegaly, and rash or other skin lesions. Other recommended tests are cranial ultrasound, hearing evaluation, and eye examination. Testing should be done for any abnormalities encountered as well as for other congenital infections such as syphilis, toxoplasmosis, rubella, cytomegalovirus infection, lymphocytic choriomeningitis virus infection, and herpes simplex virus. Some tests should be repeated up to 6 months later as there can be delayed effects, particularly with hearing. Infant feeding in areas of<unk>  virus transmission In response to the widespread transmission of<unk>  virus during the 2016 outbreak and concerns of viral genetic material detected in breast milk the World Health Organization (WHO) released a Guideline of infant feeding in areas of<unk>  virus transmission, first in 2016 and updated in 2021, where the evidence showed that despite the detection of<unk>  virus in breast milk, there is unclear evidence of transmission to the infant, and considering that<unk>  virus infection among infants is mild, the balance between desirable and undesirable effects favours breastfeeding versus not breastfeeding. According to the 2021WHO guidelines: * Infants born to mothers with suspected, probable or confirmed<unk>  virus infection or who reside in or have travelled to areas of ongoing<unk>  virus transmission should be fed according to normal infant feeding guidelines. They should start breastfeeding within one hour of birth, be exclusively breastfed for six months and have timely introduction of adequate, safe and properly fed complementary foods, while continuing breastfeeding up to two years of age or beyond. * Infants fed with expressed breast-milk from mothers with suspected, probable or confirmed<unk>  virus infection or who reside in or have travelled to areas of ongoing<unk>  virus transmission should be fed according to normal infant feeding guidelines (strong recommendation, very-low certainty of evidence). * Among infants (0–12 months) affected by complications associated with<unk>  virus infection, infant feeding practices should be modified (such as adjusting the environment, postural correction or thickening feeds) to achieve and maintain optimal possible infant growth and development (strong recommendation, very- low certainty of evidence). * Mothers and caregivers of infants affected by complications associated with<unk>  virus (such as feeding difficulties) should receive skilled support from health-care workers to initiate and sustain optimal infant feeding practices
Zika fever
Chikungunya
Leptospirosis
Yellow fever
Dengue fever
Blackwater fever
Malaria
Trench fever