The ocular tissues could offer a safe harbour for the Zika virus, allowing it to spread from a person who otherwise seems to have recovered from the infection, according to a new study.
American researchers have found that the Zika virus can live in the eyes of mice. Because the immune system is less active in the eye to protect its sensitive tissues, the ocular tissues could be acting as a reservoir for the disease in human patients who have fought off the disease in the rest of their body, Washington University researcher, Professor Michael Diamond, hypothesised.
The study, published in the journal Cell Reports, found the virus in cells in the iris, cornea, retina and optic nerve of the mice seven days after Zika’s introduction elsewhere in the body.
Professor Diamond explained that the next step in the research would be to see whether the same process occurs in humans, and if the virus persists in tissues like the cornea.
“We need to consider whether people with Zika have infectious virus in their eyes and how long it actually persists,” he emphasised.
The presence of live Zika virus in human tears would be a key finding in the ongoing research. The disease is spreading more quickly than typically happens when passed from person to person through mosquitoes.
Fellow Washington University researcher, Dr Jonathan Miner, highlighted that the virus may also be spreading through tears or other bodily fluids.
He added: “There could be a window of time when tears are highly infectious and people are coming into contact with it [the virus] and able to spread it.”
This could also mean that human tears could be tested for the virus, rather than requiring blood to be drawn, Dr Miner noted.
Previous research has found that Zika infection can significantly alter the developing eyes of foetuses, as well as their brains.
Image credit: James Gathany