Infants born to mothers infected with Zika while pregnant may not show signs of microcephaly — a birth defect characterized by an abnormally small head and underdeveloped brain — but a report released Tuesday by the Centers for Disease Control and Prevention found that some children exposed to the virus in utero may experience slowed head growth to the point of microcephaly.
The report, a collaboration by U.S. and Brazilian researchers, describes the development of 13 infants from the Brazilian states of Pernambuco and Ceará with normal head size at birth and laboratory evidence of congenital Zika infection.
Among the infants, 11 later developed microcephaly. In addition to slowed head growth and microcephaly, the children also developed neurological complications
The infants received extensive imaging, neurologic, ophthalmologic, auditory and orthopedic examinations, according to the study.
Researchers said more study is needed to fully comprehend the range of disorders associated with congenital Zika infection, and emphasized the importance of early neuroimaging for infants born to mothers who contracted the virus while pregnant.
According to the CDC, at least 1,087 pregnant women in the continental United States have tested positive for Zika. In Florida, at least 161 pregnant women have tested positive for Zika, according to the state health department. A total of 1,191 people in Florida have acquired Zika this year, including 940 travel-related cases, 236 locally acquired cases and 15 considered undetermined after a state investigation failed to identify the exact source of exposure.