In the wake of a recent surge of severe birth defects among infants born to women in Brazil who became infected with Zika virus during pregnancy, CDC officials have issued a travel alert(www.cdc.gov) for that nation and 13 other countries and territories where transmission of the virus is ongoing.
Aedes aegypti is one of a number of mosquito species known to transmit the Zika virus, so named for its initial isolation from a rhesus monkey in Uganda's Zika forest.
Between October 2015 and Jan. 9, 2016, the Brazilian Health Ministry received reports of 3,530 cases of microcephaly in newborns(portalsaude.saude.gov.br), including 46 deaths. By comparison, 147 cases were reported throughout all of 2014.
In response, the CDC is advising pregnant women in any trimester to forgo travel to the following areas: Brazil, Colombia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Suriname, Venezuela and Commonwealth of Puerto Rico.
Pregnant women who must travel to one of these areas should consult with their physician first and strictly adhere to strategies and protocols for avoiding mosquito bites(wwwnc.cdc.gov) during the trip. Women who are trying to become pregnant also should follow these precautions.
A member of the Flaviviridae family, Zika virus is a single-strand RNA virus that is transmitted primarily via the bite of infected Aedes mosquitoes. However, perinatal, in utero, and possible sexual and transfusion transmission events have also been reported. The virus takes its name from the area where it was first isolated in 1947(trstmh.oxfordjournals.org) from a rhesus monkey in the Zika forest in Uganda.
Only about one in five people infected with the virus develop symptoms. The most common symptoms of infection are a slight fever and a viral exanthem. Zika also can cause conjunctivitis, muscle and joint pain, and general malaise, which begins two to seven days after the bite of an infected mosquito. More information about the infection's clinical features, as well as diagnostic testing and management options, is available online(www.cdc.gov). No vaccine against the virus exists, and there is no specific antiviral treatment for the infection.
The full spectrum of outcomes that may be associated with infection during pregnancy and the factors that could increase fetal risk are not completely understood at this time, and health authorities in Brazil, with assistance from the Pan American Health Organization, the CDC and other agencies, continue to investigate the apparent link between maternal Zika virus infection and microcephaly in infants.
As part of this effort, CDC staff tested samples provided by Brazilian health authorities from two pregnancies that ended in miscarriage and from two infants with diagnosed microcephaly who died shortly after birth. All four mothers reported suffering from an illness characterized by fever and rash during pregnancy. In each case, genetic sequencing analysis demonstrated that Zika virus present in the samples matched the strain currently circulating in that country.
Currently, the agency is developing interim guidance for pregnant women, as well as sharing additional information about Zika virus with public health officials, clinicians and the public. In addition, efforts are underway to develop vaccines, improved diagnostics and other countermeasures to combat the virus.
CDC: Zika Virus(www.cdc.gov)