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EMERGENCY
MEDICINE
ZIKA VIRUS:
An Emerging Public Health Threat?
By Patrick S. Ramsey, MD, MSPH
Over the past several months, growing concerns have emerged re-
garding the Zika virus and potential public health risks, especially
with potential perinatal risks. Observations from a major outbreak
in Brazil have suggested an increased incidence of a rare birth defect tis) which typically resolve within 2-7 days. If two or more of the
known as microcephaly with Zika virus infection. Zika infection
has also been associated with Guillain Barre’ syndrome,
a form of ascending motor paralysis.
In early February 2016, the World Health Or-
ganization declared the Zika pandemic an “In-
ternational Public Health Emergency of
International Concern,” only the fourth time
such a declaration has ever been made by the or-
ganization. The Centers for Disease Control and
Prevention have also issued Level 2 Travel Advi-
sories to countries with a Zika outbreak and interim
guidelines for management related to Zika virus. While it
is not known at this time what the true association is between Zika,
fetal microcephaly and Guillain-Barre’ syndrome, public health and
health care professionals need to be acutely aware of the evolving
issues related to Zika and be prepared to address patient concerns
and initiate testing when indicated.
What is the Zika virus?
The Zika virus is an enveloped single-stranded RNA arbovirus in
the Flavivirus genus which is transmitted to humans primarily
through the bites of infected via Aedes mosquitoes, usually Aedes
aegypti or Aedes albopictus. The virus was originally identified in
1947 in the Zika Forest of Uganda and for many decades was not
thought to be a significant pathogen. With the past decade, however,
several outbreaks have occurred, first in Yap Providence in Microne-
sia (2007) and most recently in Brazil. The recent concerning asso-
ciation with Zika virus infection and severe fetal microcephaly, and
possibly Guillain-Barre’ syndrome has prompted the international
concern regarding the virus.
What are signs and symptoms of Zika infection
or “Zika Fever”?
The incubation period for the Zika virus is between 3 and 12
12 San Antonio Medicine • March 2016
days. 80 percent of those infected with Zika are asymptomatic. In
the remaining 20 percent, mild non-specific symptoms may develop
(acute onset of fever, maculopapular rash, arthralgia, or conjunctivi-
above symptoms are present, illness is considered consistent with
Zika virus disease and additional testing in pregnant
women.
How is Zika Transmitted?
The Zika virus is transmitted primarily by mos-
quitos from the Aedes genus. The Aedes mosquito
is found in Texas and throughout much of the
southern United States and is also the same genus
of mosquitos that transmits Yellow Fever, Dengue
Fever, and Chikungunya. The Pan American Health Or-
ganization has warned that Zika virus could continue to
spread throughout the Americas, and potentially local areas in the
United States.
Several cases of sexual transmission of Zika have been described
including the recent case in Dallas County, Texas. Evidence suggests
that the Zika virus can persist in seminal fluid for up to 10 weeks
following illness. In some of these cases, hematospermia and pro-
statitis were present in the male partner.
Concerns have been raised regarding the potential risk of Zika
transmission via blood transfusion. In a 2007 Zika outbreak in
French Polynesia, 3 percent of asymptomatic blood donors were
found to be positive for Zika virus. Several cases of transmission via
blood transfusion have also been documented outside of the United
States. Because of this concern, American Red Cross has recom-
mended that potential donors who have traveled to one of the af-
fected countries, self-defer, or postpone blood or platelet donations
for at least 28 days following their travel.
What are the concerns for pregnant women and
their partners?
For most people, Zika infection is a minor self-limited, mild ill-
ness. The concern for Zika is primarily with pregnant women given
the potential association with fetal microcephaly. Original observa-