Reminiscent of the rubella epidemic in the 1960s, in adults Zika infection may be asymptomatic or cause mild symptoms of rash, fever, headache, arthralgia, and conjunctivitis lasting a few days. Virus is typically detectable in blood around the time of symptom onset and may persist days to months in pregnant women (Driggers, 2016; Meaney-Delman, 2016). Serum IgM antibodies typically become detectable within the first two weeks after symptom onset and remain a median of four months (Oduyebo, 2017). Rarely, Guillain-Barre syndrome may develop following infection (da Silva, 2017; Parra, 2016).
The fetus can be severely infected whether or not the mother is symptomatic. Honein and coworkers (2017) describe a fetus with congenital Zika infection. Findings shown include a thin cerebral cortex, increased extraaxial space (, dilated ventricles (F,), and absent cavum septum pellucidum. (Reproduced with permission from Driggers RW, Ho (Y, Korhonen EM, et al: Zika virus infection with prolonged maternal viremia and fetal brain abnor malities, N Engl J Med. 2016 Jun 2;374(22):2142-2151.) a 6-percent overall fetal infection rate. In one report of 134 women with positive RT-PCR results, fetal mortality was 7 percent (Brasil, 2016). Among live births, the rate of fetal birth defects ranges from 5 percent-among women with possible Zika infection-to 15 percent among pregnant women with laboratory-confirmed infection in the irst trimester (Reynolds, 2017). In the most severely afected fetuses, a congenital Zika syndrome has been described that includes microcephaly, lissencephaly, ventriculomegaly, intracranial calcifications, ocular abnormalities, and congenital contractures (Honein, 2017; Moore, 2017; Soares de Oliveira-Szejnfeld, 2016). Sonographic findings from a Zika-infected fetus are shown in 64-5.
Diagnosis of this infection in pregnant women is made with detection of Zika virus RNA in blood or urine or by serological testing. Detection of Zika virus RNA by PCR confirms infection. Serological assays for Zika IgM antibodies may cross react with other flaviviruses. Thus, a positive assay result is followed by another assay containing virus-specific neutralizing antibodies (Oduyebo, 2017) . Testing recommendations and interpretation have evolved for pregnant women who are symptomatic and those who are asymptomatic but have ongoing exposure risk. his risk includes living in or traveling to an area with active local transmission. Large-scale screening programs have been described to identiy women at high risk for travelassociated Zika infection (Adhikari, 2017).
Currently, no specific treatment or vaccine is available for Zika infection, although several vaccine candidates are in development (Beigi, 2017; World Health Organization, 2017). Prophylaxis includes protective netting and insect spray to control the vector mosquito and avoidance of sexual contact with partners recently exposed. he CDC has established a pregnancy hotline (770-488-7100) and U.S. Zika Pregnanc)
Registry (ZikaPregnancy@cdc.gov) for clinicians with concerns related to management of women with Zika infection or exposure.