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By Dennis Thompson
HealthDay Reporter
MONDAY, Oct. 3, 2016 (HealthDay News) -- A new study shows that Zika virus causes so much varied damage throughout the fetal brain that researchers are suggesting the term "congenital Zika syndrome" be used to describe the numerous birth defects.
Microcephaly -- an underdeveloped skull and brain -- is the hallmark birth defect caused by Zika, which is mainly transmitted by mosquito bite.
But the study of 11 Zika-infected infants in Brazil -- the epicenter of the Zika epidemic -- found that microcephaly is only one of many brain injuries caused by the virus.
Brain scans of eight living babies and autopsies of three infants who died found lesions on the brain. These tests also showed excess fluid in the brain, an underdeveloped cerebellum, an absence of folds in the cerebral cortex, and abnormal voluntary and involuntary muscle contractions.
"Zika virus can directly kill neural cells as well as alter their differentiation pathway, making the fetal brain smaller by the end of pregnancy," said senior researcher Dr. Amilcar Tanuri. He's head of the Molecular Virology Laboratory at the Federal University of Rio de Janeiro in Brazil.
That's how microcephaly develops, he explained.
"However, it is not solely microcephaly we see. We can find other alterations that make us think of this as a congenital syndrome associated with Zika infection," he said.
Zika is the first mosquito-borne virus known to cause such devastating birth defects. Thousands of babies have been born with Zika-linked microcephaly, most of them in Brazil, since an outbreak began in South America in April 2015.
Zika infections have also been occurring in south Florida, with 59 cases as of Sept. 28, according to the U.S. Centers for Disease Control and Prevention.
Although the mosquito serves as Zika's main transmission route, researchers are discovering other modes of infection. Sexual transmission via sperm has been identified, and the New England Journal of Medicine last week reported on a case where a 38-year-old man in Salt Lake City appeared to contract Zika through physical contact with the sweat or tears of an infected patient.