CDC

December 16, 2015

CDC is aware of reports of increased numbers of babies born with microcephaly (smaller than expected head size) in Brazil. The Ministry of Health (MOH) of Brazil is concerned about a possible association between the Zika virus outbreak and increased numbers of babies born with microcephaly.

There are many causes of microcephaly

•There are many causes of microcephaly in babies (e.g., infections a mother can get during pregnancy, genetic abnormalities, exposure to toxic substances during pregnancy). Because of this, it will take time to determine the cause of microcephaly for the cases being reported in Brazil.

Microcephaly in Brazil

•Starting in October 2015, the Brazilian MOH received reports of an increase in the number of babies being born with microcephaly.

•The number of microcephaly cases are roughly 10 times higher than what the country normally sees in a year.

•Some samples from babies with microcephaly have tested positive for Zika virus infection but several affected babies have also tested negative using the same test.

•CDC is not aware of any published reports of increased numbers of microcephaly associated with other similar viral (i.e. flaviviral) diseases transmitted by mosquitoes.

Zika virus in Brazil

•Brazil reported its first case of Zika virus disease in May 2015.

•Since then, the virus has spread and has caused infections in many Brazilian states and other countries in Latin America.

•The association of Zika virus infection and microcephaly is still under investigation.

If you are pregnant and traveling to Brazil or other countries in Latin America:

CDC recommends that all people, especially pregnant women, who are traveling to Brazil and other areas in Latin America, should take precautions to avoid mosquito bites to reduce their risk of infection with Zika virus and other mosquito-borne viruses such as dengue and chikungunya.