Physicians should maintain a log of all patients who have traveled to Zika-endemic regions, as there may be a need for reconsultation with these patients when our knowledge about the virus advances and CDC recommendations are updated.
Providers must reinforce avoidance of travel to endemic regions for patients who are currently pregnant. When necessary, mosquito bite prevention is integral, including use of insect repellent, appropriate attire to shield extremities, and staying in places with windows, screen doors, or air conditioning. Environmental Protection Agency-registered insect repellents containing ingredients such as DEET, picaridin, and IR3535 are safe for use during pregnancy. Patients can also be directed to the CDC website for information on how to avoid mosquito bites: http://www.cdc.gov/features/stopmosquitoes/.
Because of the concern about maternal-fetal transmission of Zika, screening protocols have been established, as illustrated by the case scenarios below.
Case #1: Asymptomatic women with a history of travel to an endemic area.
A pregnant woman presents to your office at 19 weeks with a history of travel to Mexico between 16+0 and 16+5-weeks. She has noted mosquito bites but no illness. How would you manage this patient?
In an asymptomatic patient with a history of travel to an endemic area, serum IgM assay is now recommended between 2 and 12 weeks after exposure. If the IgM result is positive or inconclusive, serial fetal ultrasounds to screen for microcephaly and intracranial calcifications should be performed. It is important for physicians to be aware that fetal ultrasounds may not detect microcephaly or intracranial calcifications until the late second or early third trimester of pregnancy. If there are markers concerning for fetal infection, amniocentesis with RT-PCR testing for Zika virus RNA should also be considered after 15 weeks’ gestation. The sensitivity and specificity of RT-PCR testing on amniotic fluid and the maternal-fetal transmission risks from an invasive procedure are unknown at this time.
Even if the IgM result is negative, a baseline screening ultrasound should be performed, but at this time, multiple serial scans are not believed to have a role. If microcephaly or intracranial calcifications are present, amniocentesis with RT-PCR testing and retesting for IgM assay should be considered. If the patient is negative for both serologic testing and no ultrasound results in no findings, the patient can resume routine prenatal care.
Case #2: Symptomatic women with a history of travel to an endemic area.
A pregnant woman presents to your office at 26 weeks with a history of travel to Colombia on January 12th - 19th. She has noted bites, fever, and a rash. How would you manage this patient?
Clinical illness consistent with Zika virus disease is defined as 2 or more of the following signs or symptoms: acute onset of fever, maculopapular rash, arthralgia, or conjunctivitis. If your patient has a history of travel to an area with ongoing Zika virus transmission and presents with signs of an acute infection within 2 weeks of travel, serologic testing for Zika virus IgM is recommended between 2 and 12 weeks after exposure, along with fetal ultrasound to detect microcephaly or intracranial calcifications. If the serologic testing is positive or inconclusive, or if there are ultrasound findings consistent with Zika virus infection, amniocentesis with RT-PCR testing for Zika virus should be considered.
Case #3: Asymptomatic patients living in areas with endemic Zika transmission.
A pregnant woman who was living in Puerto Rico presents to your office at 32 weeks. You perform an ultrasound, which is normal. How would you manage this patient?
Pregnant women who reside in areas that are endemic for Zika virus and are asymptomatic during clinical evaluation should be offered screening for Zika virus with serologic testing for IgM antibodies at the initiation of prenatal care and again mid-second trimester. In addition, a fetal ultrasound to detect microcephaly and intracranial calcifications should be performed, ideally between 18 and 20 weeks. If these evaluations are negative, the patient should resume routine prenatal care. An additional fetal ultrasound can be considered later in the pregnancy, based on clinical suspicion.
If serologic testing is positive or inconclusive, amniocentesis with RT-PCR testing for Zika virus RNA should be considered after 15 weeks’ gestation. Serial fetal ultrasounds should also be considered to screen for microcephaly and microcalcifications. Whenever these ultrasound abnormalities are present, amniocentesis with PCR testing and retesting for IgM assay should be considered, no more than every 4 to 6 weeks if baseline was normal.
If the patient develops symptoms consistent with Zika virus during her pregnancy, she should be retested for it, even if a previous test was negative. If the symptom onset was within 7 days, amniocentesis with RT-PCR is the preferred test. However, given the possibility of a false-negative result, serologic screening for IgM antibodies should still be performed concurrently. If these evaluations are negative, the patient should resume routine prenatal care. An additional fetal ultrasound can be considered later in the pregnancy based on clinical suspicion.