The Zika virus can still cause severe defects in babies months after their births, scientists said Tuesday, issuing a grim warning to parents who thought they were in the clear once an infected mother gave birth.
The Centers for Disease Control said 13 infants with evidence of Zika infection in Brazil were born with heads within the normal size range, yet they didn’t develop properly over the following months. Eleven of them were diagnosed with microcephaly, in which the skull is much smaller than it should be because of a malformed brain.
The infants, who were born between October 2015 and January, also developed serious problems such as epilepsy and muscle weakness.
For mothers who thought they were beyond the reach of the virus after contracting the mosquito-borne disease but giving birth to a defect-free baby, the new findings are forcing them to confront new questions about the dangers posed by the epidemic.
“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,” said CDC researchers, who worked with Brazilian scientists in the northeast regions of Pernambuco and Ceara.
CDC scientists on Tuesday said their findings underscore the need to follow up with infants exposed to infection and meet their medical needs, and that more research is needed to grasp the full spectrum of complications tied to Zika. The news comes even as health officials say the Zika virus itself isn’t spreading as quickly as it did in the earlier stages of the crisis.
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The World Health Organization this month said Zika is no longer a public health emergency of international concern, though it will remain a “significant enduring public health challenge requiring intense action.”
Women who are pregnant or planning a pregnancy are still warned against traveling to some regions.
More than 1,000 pregnant women have shown evidence of Zika infection in the U.S. states and the District of Columbia, and there have been 26 instances of infants being born with Zika-related defects on the U.S. mainland.
Most of those cases were in women who traveled to Latin America or who had sexual contact with someone who traveled to the region. The only state to report local transmission was Florida, with more than 230 mosquito-bite cases in all persons.
Mosquito-borne cases on the U.S. mainland were first discovered in the Wynwood section of Miami in July, though Gov. Rick Scott cleared that neighborhood in September.
On Tuesday he said another hot spot north of Miami Beach also appears to be clear. The three-mile area hasn’t produced an infection by mosquito bite in 45 days, or three incubation cycles of the mosquitoes that carry the virus. However, active transmission is still occurring in the southern part of Miami Beach and the Little River section of Miami.
World health officials sounded the alarm over Zika in 2015 after they noticed a link between an outbreak of the disease in Latin America and a sharp uptick in the rate of babies born with microcephaly, which occurs because the virus prevents the brain from fully forming.
Heartbreaking photographs of Brazilian newborns with tiny heads raised the profile of the disease, which has infected more than 30,000 people in the U.S. territories and 230 people in Florida through mosquito bite. More than 4,000 U.S. travelers have been infected abroad before returning to the 50 states or the District.
The threat of a rash of Zika-related defects in the 50 states and Puerto Rico drove congressional efforts this year to pass a $1.1 billion emergency response package.
Now the Department of Health and Human Services is working to dole out tens of millions of dollars in grant funding this fiscal year to detect Zika-related birth defects, refer families to services and fund treatment.
Looking ahead, voters in the Florida Keys approved a referendum that would allow British company Oxitec to release genetically modified mosquitos in an attempt to eradicate the Aedes aegypti breed that also carries Zika and related viruses like dengue. Some 58 percent of voters favored the plan.
The modified males would mate with wild aegypti females and produce unviable offspring, therefore trimming the local population.
However, residents of the proposed release site — Key Haven — opposed the measure, meaning Oxitec and the Florida Keys Mosquito Control District will have to search for other sites that meet FDA requirements, according to mosquito control board Commissioner Phil Goodman.
He said they hope to start releasing the modified mosquitoes by spring.
• Tom Howell Jr. can be reached at thowell@washingtontimes.com.
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