The risk posed by the Zika virus to developing fetuses is likely far greater than current estimates suggest, a top U.S. health official said.
Microcephaly, a rare birth defect in which babies develop abnormally small heads, is one of a constellation of Zika-associated problems increasingly being seen in children born to mothers infected during pregnancy with the Zika virus, reports Reuters.
Other types of birth defects observed include seizures, deafness, blindness and a range of neurological and developmental abnormalities.
Earlier this year, a U.S. analysis estimated the risk of microcephaly following a mother’s infection with the virus during the first trimester of pregnancy at between 1 percent and 13 percent.
That figure does not include the overall risk of risk of birth defects, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said during a panel discussion on Zika.
“If you’re talking about any congenital defect I think it’s going to be much higher than 13 percent,” he said. “I think we’re going to see something very disturbing.”
The World Health Organization declared a global health emergency over Zika’s link to microcephaly in February. The mosquito-borne virus has spread rapidly through the Americas, with Brazil hit hardest so far. On Wednesday, the U.S. Congress approved $1.1 billion to fund research and efforts to contain Zika.
Speaking on the same Zika panel on Thursday, Dr. Marcia Castro, an associate professor of demography at Harvard, said physicians in Brazil are studying the initial wave of babies impacted by Zika who are now reaching their first birthday.
In addition to seizures, agitation and frequent crying, these children are also exhibiting a severe type of reflux that prevents them from eating, she said, adding that it is unclear how long these children will live.
“Another study with mice shows Zika also affects the brain of an adult,” she said, potentially impacting long-term memory and depression.
As of Sept. 17, Brazil had confirmed 1,949 cases of microcephaly linked to Zika, mostly concentrated in the country’s northeast region. Another 3,030 cases are still under investigation. In the United States, the virus has infected tens of thousands of people on the island territory of Puerto Rico.