CDC researchers in collaboration with researchers from the United States and Brazil investigated the first series of infants with laboratory evidence of congenital Zika virus infection documented to have onset of microcephaly after birth.
The report, published today in CDC’s Morbidity and Mortality Weekly Report, describes 13 infants in Brazil with congenital Zika virus infection who did not have microcephaly at birth, but later experienced slowed head growth. Among these infants, 11 later developed microcephaly. Slowed head growth and microcephaly were accompanied by significant neurologic complications. Although microcephaly was not present at birth, the infants had other brain abnormalities consistent with congenital Zika syndrome.
The study reveals that among infants of mothers exposed to Zika virus during pregnancy, the absence of microcephaly at birth does not rule out congenital Zika virus infection or the presence of Zika-related brain abnormalities. [CDC]
The study focused on 13 babies born in Brazil late last year and earlier this year. All had head heads that were a little small at birth, but within the normal range. Over the next five to 12 months, doctors noted their heads weren’t growing at normal rates. Eleven were eventually diagnosed with microcephaly.
Many of the children also developed other problems that have been linked to Zika, including epilepsy, problems swallowing, muscle weakness and inflexible joints.
Dr. Peter Salama, chief of emergencies at the World Health Organization, told reporters in Geneva on Tuesday that understanding of the complications from Zika continues to evolve. “We are also learning lot every day,” he said. [TAMPABAY]