Researchers in Brazil are reporting vision-threatening retinal lesions in babies born with microcephaly that appear to be linked to infection with the mosquito-borne Zika virus.
Rubens Belfort Jr., MD, PhD, and colleagues conducted the study in December 2015, recruiting 29 infants with microcephaly and a presumed Zika diagnosis. 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.
Eye abnormalities were detected in 10 of the 29 infants. The majority of cases had bilateral macular and perimacular lesions (64.7%), followed by optic nerve abnormalities in 8 eyes (47.1%), bilateral iris coloboma in 1 patient (2 eyes [11.8%]) and lens subluxation in 1 eye (5.9%).
Dr. Belfort advises physicians to check infants with abnormally small heads for vision problems.
However, the association does not prove a cause-and-effect relationship. Dr. Lee Jampol and Dr. Debra Goldstein, from Northwestern University Feinberg School of Medicine in Chicago, note 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. They also stress that the ophthalmologic manifestations of congenital Zika virus infection are not yet well described.
"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."
Since the Zika epidemic first surfaced in Brazil last spring, the virus has 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.
The Associated Press this week reported some positive news from Colombia. Although 3,177 pregnant women in Columbia 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.
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.