TUESDAY, Feb. 9, 2016 (HealthDay News) -- Eye defects may occur in babies born with microcephaly that seems to be linked to infection with the mosquito-borne Zika virus, researchers report.
Since a Zika virus outbreak began in Brazil last April, there has been an unusual rise in the number of babies born with microcephaly (an abnormally small head). As of January, there were more than 3,000 newborns in that country with the birth defect, according to Brazilian health officials.
In this new study, the eyes of 29 infants with microcephaly were evaluated. Of the 29 mothers, 23 reported suspected Zika virus infection signs and symptoms during pregnancy, including rash, fever, joint pain, headaches and itching.
Of those 23 mothers, 18 said they had symptoms of Zika during the first trimester of their pregnancy, the investigators found.
Eye abnormalities that can threaten vision were detected in 10 of the 29 infants, according to the study published online Feb. 9 in the journal JAMA Ophthalmology.
The findings could help guide doctors treating infants with microcephaly, Dr. Rubens Belfort Jr., from the Federal University of Sao Paulo, Brazil, said in a journal news release.
However, Dr. Lee Jampol and Dr. Debra Goldstein, from Northwestern University Feinberg School of Medicine in Chicago, pointed out in an accompanying journal editorial that microcephaly may have several causes. The birth defect may be genetic, metabolic, drug-related or due to problems during pregnancy such as malnutrition, infection or lack of oxygen.
"The present 20-fold reported increase of microcephaly in parts of Brazil is temporally associated with the outbreak of Zika virus," they wrote. "However, this association is still presumptive because definitive serologic testing for Zika virus was not available in Brazil at the time of the outbreak, and confusion may occur with other causes of microcephaly," Jampol and Goldstein explained.
"Similarly, the currently described eye lesions are presumptively associated with the virus," they added.
However, the association does not prove a cause-and-effect relationship.
While the Zika epidemic first surfaced in Brazil last spring, Zika virus has since spread to 30 countries and territories in South and Central America and the Caribbean. The World Health Organization now estimates there could be up to 4 million cases of Zika in the Americas in the next year.
But over the weekend, a small ray of hope on that front emerged in Colombia. Although 3,177 pregnant women in that country have been diagnosed with the virus, President Juan Manuel Santos said there's no evidence Zika has caused any cases of the microcephaly birth defect, according to the Associated Press.
On Monday, the Obama administration announced that it is seeking $1.8 billion in emergency funds from Congress to combat the threat of the Zika virus. And the U.S. Centers for Disease Control and Prevention on Friday advised that pregnant women with a male partner who has traveled to, or lives in, an area where Zika infection is active should refrain from sex or use condoms during sex until the pregnancy is over.
The U.S. Centers for Disease Control and Prevention has more on the Zika virus.