Research Study Finds that Zika Virus Can Live in Tears, Cause Eye Disease
The study suggests that the eye can be a reservoir for the virus and that it may be spread by tears
It has been well publicized that the Zika virus can have devastating effects on unborn children. What has not been known about until now is the less dangerous, but still harmful, effect the virus can have on others.
Although symptoms in many people are so mild that they go unnoticed, others experience red eyes and even pain behind the eyes. Now research conducted at Washington University School of Medicine has revealed the reason.
The virus is able to live in tears.
The scientists found that Zika can survive in the eyes and discovered traces of the virus's genetic material in tear drops. This, they say, explains why some Zika patients also develop a condition known as uveitis, which can threaten eyesight.
"Our study suggests that the eye could be a reservoir for Zika virus," said Dr. Michael Diamond, a senior author of the study. "We need to consider whether people with Zika have infectious virus in their eyes and how long it actually persists."
Women infected with Zika are likely to give birth to babies who have microcephaly, a condition in which the baby's brain does not develop completely. It is also now known that roughly one third of babies infected with the virus while still in the womb also contract eye disease, e.g. optic nerve inflammation.
Adults who have the virus may contract conjunctivitis, which causes redness and itching in the eyes. A few may also develop uveitis, though these cases are rarer.
The researchers found through experiments on mice that Zika can infect the eyes within a period of about seven days, but they do not yet know how the virus gets there.
Regarding transmission of the virus, it was already known that it can be transmitted through sexual contact, but this study suggests that an infected person's tears may also be capable of transmitting it.
"Even though we didn't find live virus in mouse tears, that doesn't mean that it couldn't be infectious in humans," commented lead author Dr. Jonathan J. Miner.
If this is the case, it may explain the speed with which Zika is spreading. Researchers are searching for additional sources of contagion because the virus is spreading more quickly than it would if mosquitoes were its only source.