Zika is a generally mild illness caused by a virus primarily transmitted through the bite of infected Aedes mosquitoes. The U.S. has 318 reported travel-associated cases; all were travel-associated/imported and included 11 reports of sexual transmission, 157 pregnant women and 1 Guillain Barre syndrome. Approximately one in five people infected with the virus develop the disease, and most people who are infected do not develop symptoms. The most common symptoms of Zika virus are fever, rash, joint pain, and conjunctivitis (red eyes). Symptoms typically begin two to seven days after being bitten by an infected mosquito. In some cases, Zika virus may be transmitted sexually in semen. It can also be transmitted from a pregnant mother to her baby during pregnancy or around the time of birth. Fetuses and infants of pregnant women infected with Zika virus are at increased risk for microcephaly, intracranial calcifications, central nervous system abnormalities and other severe brain defects. The CDC recently estimated that women infected during pregnancy may have a 13% chance of giving birth to a child with microcephaly.
In the recent publication in the NEJM Zika, Virus and Birth Defects — Reviewing the Evidence for Causality, Rasmussen et al. demonstrate that there is “sufficient evidence has accumulated to infer a causal relationship between prenatal Zika virus infection and microcephaly and other severe brain anomalies”. According to the SMFM’s current guidelines, all women who are at risk of infection due to a travel history to an endemic area (http://www.cdc.gov/zika) or exposure through unprotected sex with an infected individual should be offered serum serological screening for Zika virus regardless of whether they are presenting with symptoms. Patients whose serological testing is IgM positive or inconclusive may be offered amniocentesis in combination with serial ultrasounds to assist in identifying microcephaly and microcalcifications. A positive Zika virus RT-PCR result from amniotic fluid would be suggestive of intrauterine infection. This information would be useful for pregnant women and their health care providers to assist in determining clinical management (e.g., antepartum testing, scheduling serial ultrasounds, delivery planning). A negative Zika virus RT-PCR result from amniotic fluid may prompt a work-up for other causes of microcephaly (e.g., other infections, genetic disorders).
CytoGenX is actively coordinating with local health departments and the CDC for Zika testing in pregnant women. Recently the CDC issued guidelines for the prevention of Zika virus infection in pregnant women.