LONDON, England, Monday August 17, 2015 – Recent findings suggest that vision impairment may be an under-reported effect of chikungunya, after a woman who contracted the mosquito-borne virus while vacationing in Grenada lost some of the sight in her right eye permanently.
That’s according to Dr Abhijit Mohite, who treated the woman and co-authored the report on her case.
Dr Mohite, an ophthalmologist at the West Midlands Postgraduate Deanery and Queen’s Hospital in the United Kingdom, stressed the importance of early treatment to prevent lasting vision loss.
The subject of the report was a 69-year-old woman who visited Grenada in July 2014. During her stay, she was bitten by mosquitoes and developed the flu-like illness, fever, rash and joint pain associated with chikangunya.
She also developed muscle weakness in her face, and received steroids from a local doctor to treat it, according to the study.
The following month, the woman returned to the United Kingdom. Although her symptoms appeared to clear up, apart from some lingering joint pain and stiffness, she began to experience difficulty seeing with her right eye, according to Live Science.
“Her main symptom was that she felt she could not see the lower half of her vision in the right eye,” Mohite said. “This had come about only a day before she came to see us, and about three weeks after she returned from Grenada.”
The patient’s central vision initially appeared fine, and she could see with normal acuity, 20/20 vision, with both eyes.
As the doctors raced to diagnose her illness, however, her right optic nerve swelled and damaged her vision. Within days, she had 20/80 vision, and could read only to the third line down on the eye chart.
A blood test confirmed that the patient had chikungunya, but the doctors still had to rule out other possible causes of her vision loss, such as another infection, inflammation, or a tumour pressing on the optic nerve or pathway.
As soon as further tests ruled out these conditions, the doctors prescribed steroids to treat the woman’s optic nerve, which had swelled as part of her body’s inflammatory reaction to the virus, Mohite said.
“One of the main risks of high-dose steroids is that they can exacerbate an infection, if she had another infection somewhere else in the body. This is why we had to await all the other tests before we could start steroids, and this took six days,” he added.
During the six days it took for doctors to run all the tests and prescribe the steroids, about half of the nerve cells in the patient’s optic nerve had died. And while the steroids decreased the inflammation, they couldn’t undo all the damage.
“The steroids, unfortunately, were not started soon enough in our patient,” Mohite said. The vision loss was permanent.
Although this is the first known case of a woman in the United Kingdom developing this problem, doctors elsewhere have noted eye problems in people infected with chikungunya.
Experts say it is not known how often chikungunya infections may lead to eye problems.
According to Dr Aileen Marty, director of the Florida International University Health Travel Medicine Program and Vaccine Clinic: “It’s underreported because people don’t even do the studies to figure out if it’s chikungunya or another infection.
“My personal opinion is that it’s really not an uncommon event to get some level of eye involvement,” added Dr Marty, who was not involved in the case report.
Meanwhile, the authors of the report said that the woman’s case could help doctors understand that eye-problem complications associated with chikungunya should be treated within days.
The report was published online July 28 in the journal BMJ Case Reports.
Researchers first recognized chikungunya in Tanzania in 1952. It has since spread from Africa and Asia to the Caribbean, Latin America and parts of the United States.
The name is based on an East African word that means “that which bends,” because people infected with the virus are often bent over with muscle and joint pain. Other symptoms include fever, headache, nausea, vomiting and rash.
In July 2014, a Florida man became the first person to get chikungunya in the United States, according to the Centers for Disease Control and Prevention (CDC).
The disease is transmitted by two species of mosquito — Aedes aegypti and Aedes albopictus — that are recognizable by their black and white legs.