Zika virus is a single-stranded RNA virus that is transmitted to humans primarily through the bite of an infected Aedes species mosquito. In January of 2015, the CDC first reported on local transmission of the virus in the Western Hemisphere and confirmed the presence of the virus is several infants with microcephaly and in fetal losses in women infected during pregnancy. Clinical manifestations have now expanded to include other central nervous system abnormalities, growth restriction, and positional anomalies of the extremities prenatally and ocular abnormalities, hearing loss, and cardiac defects postnatally. While some patients infected with the virus show clinical symptoms such as fever, maculopapular rash, arthralgia, or conjunctivitis, other patients are asymptomatic. There is also currently no treatment, so care is focused on supportive care including rest, fluids, and analgesics and antipyretics.
For patients who are currently pregnant, the CDC recommends Zika virus testing for the following exposed patients. Exposure includes living in, traveling to, or having unprotected sex with someone who lives in or traveled to an area with risk of Zika. We usually refer patients to the CDC website for the most updated list of areas with local Zika transmission. Of note, Brownsville, TX and Miami-Dade County are no longer Zika cautionary areas.
- Symptomatic pregnant women with possible Zika exposure
- Asymptomatic pregnant women with ongoing possible Zika exposure
- Pregnant women with a possible exposure who have a fetus with prenatal ultrasound findings consistent with congenital Zika virus infection.
For patients who are currently pregnant with recent possible exposure to Zika (for example, travel to a Zika area) but no ongoing exposure, some patients may choose to be tested based on personal values and preferences. A discussion of the risks and expected outcomes of testing is recommended for these patients.
Essentially, testing of serum and urine by Zika virus RNA nucleic acid testing (NAT) is recommended for symptomatic women with specimen collection <14 days after symptom onset, asymptomatic women with specimen collection <14 days from exposure, and women with ongoing exposure. Zika virus IgM testing of serum is recommended for specimen collection ≥ 14 days from symptom onset or exposure.
The CDC recommends serial ultrasounds every 3-4 weeks for women with laboratory evidence of Zika infection. For our patients with an exposure but no laboratory evidence of Zika infection or no testing, we recommend the detailed anatomy scan at 20-22 weeks and a follow up growth scan at 28-32 weeks with possible repeat at term to evaluate for fetal anomalies associated with the Zika virus.
For patients who plan to conceive, the CDC recommends that women wait for at least 2 months after the date of her last possible Zika virus exposure and men wait for at least 6 months. Pre-conceptional Zika virus IgM testing is no longer recommended for asymptomatic patients who are planning to conceive. This change in IgM testing for asymptomatic patients without ongoing exposure is due to the high false positive rate of IgM testing and the prolonged presence of IgM in serum after exposure.
Carnegie Imaging for Women blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!