All HIV-infected and uninfected study participants will be tested for ZIKV. Enrolled women will be followed throughout their pregnancy and up to six weeks postpartum. Infants born to enrolled women will be followed for a full year after birth. Thereafter, the infants born to women at continental U.S. and P.R. sites also implementing the Surveillance Monitoring for Antiretroviral Therapy (ART) Toxicities (SMARTT) study may be followed up yearly until adulthood through SMARTT depending on the availability of funds.