ZIKA VIRUS – GUIDANCE FOR
PHYSICIANS
Sarah Moyer MD, MPH, and Katherine Pohlgeers, MD, MS
Z
ika virus is
suspected in
the precipitous
rise in cases of microcephaly in newborns in
Brazil and other areas
of South and Central
America.
On March 9, the Centers for Disease Control and Prevention
(CDC) confirmed a case of Zika in a Jefferson County man who
became infected on a trip to Central America. The man has made
a full recovery. There have also been cases reported in the neighboring states of Indiana and Tennessee. All U.S. cases were either
among individuals who had traveled to a Zika infected area or who
had been infected by sexual contact with an individual who had
contracted the virus in an infected region.
On February 22, the CDC deployed a 16-member team of
epidemiologists to Brazil and began training dozens of Brazilian
teams as part of a case control study to determine whether the Zika
virus is the cause of the upsurge in cases of microcephaly throughout
the country and the region.
CDC formed eight teams of American and Brazilian investigators
who fanned out into the region of Joao Pessoa in northeastern
Brazil searching for about 100 mothers who gave birth to babies
with microcephaly since the Zika outbreak began. Investigators
hoped that this study would either provide more definitive evidence
establishing the link between Zika and microcephaly or identify
other factors that may be to blame, either in combination with Zika
or instead of Zika.
Zika virus is a mosquito-borne flavivirus primarily transmitted by
Aedes mosquitoes, the same mosquitoes that spread Chikungunya
6
LOUISVILLE MEDICINE
and dengue. Infected mosquitoes can then spread the virus to other
people through bites. It can also be transmitted from a pregnant
mother to her fetus during pregnancy or around the time of birth.
To date, there are no reports of infants getting Zika virus through
breastfeeding. Because of the benefits of breastfeeding, mothers are
encouraged to breastfeed even in areas where Zika virus is found.
Sexual transmission of Zika virus can also occur, although there
is limited data about the risk. Given the potential risks of maternal
Zika virus infection, pregnant women whose male partners have or
are at risk for Zika virus infection should consider using condoms
or abstaining from sex.
An estimated 80 percent of persons infected with Zika virus are
asymptomatic. Symptomatic disease is generally mild. The most
common symptoms of Zika virus include fever, rash, joint pain
or conjunctivitis. Symptoms typically begin two to seven days
after being bitten by an infected mosquito. Severe disease requiring
hospitalization is uncommon, and fatalities are rare. Once a person
has been infected, he or she is likely to be protected from future
infections.
The concern is that Zika infection during pregnancy may be
linked to serious birth defects, notably microcephaly – a condition
in which the baby is born with an abnormally small head. Babies
with microcephaly can have a range of other problems, depending
on how severe their microcephaly is. Microcephaly has been linked
with seizures, developmental delay, intellectual disability, problems
with movement and balance, difficulty swallowing, hearing loss
and vision problems.
There have also been cases of Guillain-Barré syndrome reported
in patients following suspected Zika virus infection. The relationship
between Zika virus infection and Guillain-Barré syndrome is being
investigated.