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EMERGENCY
MEDICINE
tions from the outbreak which started in Brazil in 2015, noted a and treated with permethrin and use of mosquito repellent with
large surge in the cases of fetal microcephaly from an annual inci- DEET (N,N-diethyl-m-toluamide), picaridin, oil of lemon euca-
dence of 0.05/1000 live births in 2010-2014 to over 1/1000 live lyptus (OLE) or IR3534 should be used regularly when outdoors.
births in 2015. Small numbers of cases have documented evidence These measures can be used safely during pregnancy.
of Zika vertical transmission to the fetus. Zika virus RNA has been
identified in fetal tissue from early missed abortions, amniotic fluid, While there have been a number of cases of Zika diagnoses in
term neonates and the placenta. Texas, including at least one in Bexar County so far, all but one of
these cases was acquired from travel outside of the United State and
Much is still unknown about the potential risks for Zika virus in- the last case was acquired by sexual transmission from an individual
fection in pregnancy. Some questions include: Is there a clear plau- who traveled outside of the United States. Because the mosquito
sible pathophysiology, is there a specific gestational age range at risk, vector, Aedes species of mosquito are found throughout South Texas,
are there clinical co-factors which influence risk, are there any long- local outbreaks may be possible. Locally measures in San Antonio
term risks of maternal infection, etc? Preliminary reports from and South Texas are being put in place to coordinate community
Colombia have noted 2,100 cases of Zika infection in pregnancy, mosquito control. Individuals can assist in these measures by remov-
yet at this time, no reported increased rates of microcephaly have ing containers with stagnant water, such as old tires, barrels, which
been noted. Much research is ongoing at this time to delineate these can serve as a mosquito breeding ground.
issues, however, until we have a better understanding of these issues
and the true risk potential, making informed management decisions What should health providers do?
following potential Zika exposure or actual infection is challenging. All health care providers caring for pregnant women should ask
In addition to the concern for microcephaly, early reports from their patients about recent travel. Current CDC guidelines recom-
French Polynesia and others have suggested potential association be- mend Zika testing for all pregnant women who have traveled to one
tween the Zika virus with Guillain Barre’ syndrome. The relation- of the countries where Zika is endemic (SEE FIGURE page 14).
ship between Zika and this neurologic condition remains to be Testing can be offered to pregnant women without symptoms any-
defined and likely not isolated to pregnant women. time between two and 12 weeks following travel. If performed, test-
ing should include Zika virus IgM, and if IgM test result is positive
Emerging concerns exist regarding the documented cases of sexual or indeterminate, neutralizing antibodies evaluated on serum spec-
transmission and risks to pregnant women and women considering imens. For pregnant women presenting with clinical illness sugges-
pregnancy in the future. We know today that Zika virus is cleared tive of Zika, testing can include Zika virus reverse
from the bloodstream by one week but may persist in seminal fluid transcription-polymerase chain reaction (RT-PCR), and Zika virus
for up to 10 weeks following illness. Partners of pregnant women immunoglobulin M (IgM) and neutralizing antibodies on serum
who travel to a Zika-endemic country are advised to practice safe specimens. Testing can be coordinated through the San Antonio
sex and take precautions for the remainder of the pregnancy. No Metropolitan Health District and the State Health Department.
clear guidelines presently exist to guide counseling or recommenda- Providers should evaluate their local clinic/hospital environment and
tions for future pregnancies. develop processes to facilitate testing.
How to prevent Zika infection? In pregnant women who test positive or inconclusive for Zika in-
There is no vaccine for Zika virus at this time and will likely be fection, serial prenatal ultrasound assessments every 3-4 weeks are
recommended to assess for development of microcephaly or intracra-
years in the making. For now, avoiding exposure is the most effective nial calcifications. Consideration of amniocentesis is also recom-
approach to prevent infection. Pregnant women are advised to avoid mended in these cases to test for Zika virus with RT-PCR testing.
travel to areas where Zika is endemic. These areas include Mexico, In pregnant women with negative testing for Zika, a baseline pre-
parts of South America and much of Central America and natal ultrasound is recommended to assess for the above abnormal
Caribbean. An updated list of affected countries can be found on findings. When these are absent, the CDC currently recommends
the CDC website (www.cdc.gov/zika). resumption of routine prenatal care. If abnormal findings are pres-
ent, retesting of the mother and consideration of amniocentesis is
If travel to one of the affected countries is unavoidable, pregnant recommended. The Society of Maternal-Fetal Medicine has issued
women traveling to countries with reported Zika virus infection clinical guidance for microcephaly diagnosis recommending that
should avoid contact with mosquitos by staying inside or in a
screened-in area. Long-sleeved shirts and long pants should be worn Continued on page 14
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