Little is known about Zika virus (ZIKV) biology and its pathogenesis in humans. ZIKV has been detected in blood, urine, semen, cerebral spinal fluid, saliva, amniotic fluid, and breast milk. In most ZIKV infected individuals, the virus is detected in the blood from a several days to one week after the onset of symptoms and has also been found to persist longer in urine and semen. Sexual transmission of ZIKV has been recently documented. Without a more granular understanding of the kinetics of ZIKV infection across biologic compartments it will be difficult to devise rational measures to prevent the transmission of the virus. This will be an observational cohort study of men and women, aged 18 years and above, including symptomatic participants with positive reverse transcriptase-polymerase chain reaction (RT-PCR) test in blood and/or urine and their symptomatic or asymptomatic household/sexual contacts with positive RT-PCR in blood and/or urine. Specimens to be collected at pre-established intervals and tested for ZIKV RNA by RT-PCR are blood, semen, vaginal secretions, saliva, tears, sweat, urine, rectal swab, menstrual blood and breast milk (if applicable). Participants will be recruited from collaborating clinics in selected locations with high population density, high circulation of the virus, strong community network, and serviced by laboratory facilities with capacity to perform the necessary tests. All participants will be followed up for 12 months, to assess detectability at longer time intervals, reactivation or reinfection. Analyses of antibody response, including circulating immunoglobulins M and G (IgM and IgG), will be performed in parallel to RT-PCR tests. Plaque reduction neutralization test will be performed in specimens of participants who are found to be simultaneously positive for ZIKV and dengue. Specific analysis will be performed to determine if socio-demographic characteristics, comorbidities and co-infections influence the persistence of the virus in the body fluids.
