New York, Feb 10 (IANS): Vision-threatening eye abnormalities in infants in Brazil with microcephaly - a birth defect characterised by an abnormally small head -- may be associated with infection with Zika virus, says a new study.

Zika virus is spread to people through mosquito bites and according to US Centres for Disease Control and Prevention the most common symptoms of Zika virus disease are fever, rash, joint pain, and conjunctivitis (red eyes).

"This study can help guide clinical management and practice, as we observed that a high proportion of the infants with microcephaly had ophthalmologic lesions. Infants with microcephaly should undergo routine ophthalmologic evaluations to identify such lesions,” the researchers said.

The researchers and colleagues from the Federal University of Sao Paulo, Brazil, evaluated the ocular findings of 29 infants with microcephaly with a presumed diagnosis of congenital Zika virus.

The study was conducted during December 2015 and all the children and their mothers were evaluated at the Roberto Santos General Hospital, Salvador, Brazil.

Of the 29 mothers, 23 (79.3 percent) reported suspected Zika virus signs and symptoms during pregnancy, including rash, fever, arthralgia (joint pain), headache and itch.

Among the 23 mothers who reported symptoms during pregnancy, 18 or 78.3 percent reported Zika virus symptoms during the first trimester of pregnancy, according to the report.

Vision-threatening abnormalities of the eye were observed in 10 of the 29 infants (34.5 percent) with microcephaly.

However, experts have cautioned that 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.

The study was published online in the journal JAMA Ophthalmology.