The Zika virus has been found in fluid around the eyes of some patients, shedding new light on how the virus affects healthy adults, according to a study published today in Journal for the American Medical Association Ophthalmology.

Some people infected with Zika develop conjunctivitis, an eye infection common among children known as “pink eye,” the study authors explained.The eyes of six patients infected in South America were swabbed by researchers from the Guangdong Provincial Institute of Public Health in China. When they tested their eye fluids, they found Zika virus RNA.

“Here we have some evidence when the adult is infected, it would appear that highly specialized neural tissue is infected,” Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical School, said. He said the next step would be examining if the virus caused any vision problems.

The virus was detected five days after the onset of their symptoms. In one traveler, it was detected in eye swab samples seven days later. Schaffner said researchers are still learning the many ways the Zika virus, which usually causes mild symptoms including fever, fatigue and pink eye, can affect adults and how it can remain in different parts of the body.

Zika has previously been identified in urine, semen, saliva and breast milk, but the researchers noted that their findings show it may also be detected in eye fluid.

The investigators pointed out, however, that more research is needed before new recommendations can be made on the use of eye swabs instead of other body fluid samples when diagnosing Zika infection. They added that the virus may not linger as long in eye fluid as it does in urine and saliva.

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The findings also raise concerns about the possible spread of Zika virus through corneal transplants, the study authors suggested.

Research References:

  1. Jiufeng Sun, PhD, De Wu, PhD Haojie ZhongDawei GuanHuan ZhangQiqi TanChangwen Ke, PhD.Presence of Zika Virus in Conjunctival Fluid. JAMA Ophthalmol. Published online September 15, 2016. doi:10.1001/jamaophthalmol.2016.3417