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Zika virus outbreak prompts US to issue travel alert to pregnant women

BMJ 2016; 352 doi: (Published 18 January 2016) Cite this as: BMJ 2016;352:i306
  1. Michael McCarthy
  1. 1Seattle

Prompted by reports from Brazil linking Zika virus infection with a surge in cases of fetal and newborn microcephaly, the US Centers for Disease Control and Prevention has issued a travel alert urging women who are pregnant or who are trying to become pregnant to postpone traveling to countries where there is ongoing transmission of the virus. Such women who must travel to such areas should consult their healthcare provider first and strictly follow steps to avoid mosquito bites during their trip, the CDC said.

The warning, issued on Friday 15 January, came on the same day that health officials in Hawaii reported that the mother of a baby recently born with microcephaly on the island of Oahu had likely acquired Zika infection while residing in Brazil and that her newborn was infected in the womb.

Zika virus, a single stranded RNA virus of the flaviviridae family, genus flavivirus, was first discovered in the Zika Forest in Uganda in 1947. Until recently the virus was largely confined to Africa, southeast Asia, and the Pacific islands but was reported in the western hemisphere on Easter Island in 2014. Since then Zika has been reported in 18 countries and territories in Latin America and the Caribbean: Brazil, Barbados, Colombia, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Puerto Rico, Saint Martin, Suriname, and Venezuela. The first case of Zika virus in the United States was reported earlier this month in a traveler who recently returned from Latin America to Texas.1

The first case of Zika virus infection in Brazil was confirmed in May 2015. Outbreaks were subsequently reported across the country, together with a marked increase in congenital malformations, including 3500 cases of microcephaly.2 CDC scientists investigating the outbreak have detected the virus in samples provided by Brazilian authorities from two pregnancies that ended in miscarriage and from two infants with microcephaly who died shortly after birth. Testing indicated that the virus was in the brain of both infants. All four mothers had reported having experienced a fever and rash illness consistent with Zika virus disease during their pregnancies. Genetic sequence analysis by CDC scientists showed that the virus in the four cases was the same as the Zika virus strain currently circulating in Brazil.

In a teleconference with reporters Lyle Petersen, director of the CDC’s division of vectorborne disease in Fort Collins, Colorado, cautioned that more research was needed to define the relation between the virus and microcephaly. “Although these test results provide new evidence of a link between the infection and poor pregnancy outcomes, we don’t yet know what other outcomes might be associated with infection during pregnancy and other factors that might increase risk to the fetus. More laboratory testing and other studies are planned to learn more about the risks of Zika virus infection during pregnancy,” he said.

The Zika virus is spread by the bite of a mosquito that has acquired the virus, usually by feeding on an infected person. About a fifth of people infected with the virus become ill. Symptoms are usually mild and include fever, rash, joint pain, and conjunctivitis, as well as myalgia, headache, and vomiting. Severe illness is uncommon and reports of death are rare, the CDC said. There is currently no vaccine to prevent Zika infection and no specific drug to treat it. Treatment is symptomatic.


Cite this as: BMJ 2016;352:i306


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