Dr. Susan Kovats, an OCRID investigator, discusses the West Nile virus and its correlation with rainfall with the Oklahoman Newspaper
06/16/2015
Dr. Susan Kovats, an OCRID investigator, discusses West Nile virus and its correlation with increased rainfall. Dr. Kovats is funded by NHLBI to study dendritic cell-mediated response during influenza virus infection.
Oklahoma: In May, rain fell in buckets, leaving area lakes, rivers and fields overflowing. With the increased volume of standing water, many people anticipate a record crop of mosquitoes.
But does a higher population escalate the risk for mosquito-borne diseases, particularly
West Nile virus?
Oklahoma Medical Research Foundation scientists Susan Kovats, Ph.D., and Jose Alberola-Ila,
M.D., Ph.D., who have spent the past two years researching the virus, say there is
no scientific correlation between increased rainfall and increased incidences of West Nile.
“It’s a very strange virus,” Kovats said. “Ever since it came to the U.S. in New
York in 1999, it has marched across the U.S. season by season, but it has a certain
random component that we don’t understand. Some seasons there just isn’t much of the
virus in certain regions, and it’s difficult to say why.”
In fact, Alberola-Ila said, there is more evidence to support a mild winter as a predictor
for a West Nile-heavy season. “Even an increase in mosquito population doesn’t necessarily
up the risk for infection as a result.”
Symptoms of West Nile fever can mimic those of influenza: fever, body aches, headache
and general fatigue. Other symptoms can include a rash on the torso and swollen lymph
glands. The length of the illness can vary from a few days to several weeks. Those
with the more severe form often require hospitalization.
Precaution rather than panic
Mosquitoes can transmit anywhere from 10,000 to 1 million viruses in a single bite, Kovats said. “It’s likely you don’t need a lot of mosquito bites to become infected. You just have to run into the wrong mosquito.”
But before those internal alarms sound, there is good news for those concerned about
the virus. According to the state Department of Health, more than 80 percent of people
infected never become ill. Those who do often suffer from little more than fatigue,
fever, headaches and body aches that go away on their own.
More severe cases can lead to neurological diseases, meningitis or in some cases death.
But according to the Center for Disease Control and Prevention, only 1 percent of
people bitten by a West Nile-infected mosquito will become seriously ill.
The worst year for West Nile in Oklahoma was 2012 with 161 nonfatal cases and 15 deaths.
There were 76 nonfatal cases and eight deaths in 2013. Only 18 cases were reported
last year, with no fatalities, according to the CDC.
The virus is most likely to become serious in the elderly and those with compromised
immune systems.
Even though your odds of contracting a serious form of the virus are slim, it is best
to remember insect repellant on your way to any outdoor activities in coming months.
“I don’t think there should be any panic factor,” Kovats said. “Still, it’s wise
to minimize mosquito bites for a variety of reasons, not just West Nile. If you are
a healthy person, the risks are slim.”
Long-term view
Kovats and Alberola-Ila study a key regulator of the immune system called dendritic cells. In particular, they’re examining how the cells respond when the body is attacked by viruses like West Nile.
“We are looking at the ability of these cells in the skin to shut down the virus as
well as call in other cells in the immune system,” Kovats said. “It’s a race between
the host trying to shut down the virus and, conversely, the virus trying to shut down
the host.”
The study, which the pair conducted with OMRF colleagues Sean Turner and Amie Simmons,
looks at what happens in the early stages of infection in the skin. Their findings
may lead to a way to best position a person for an appropriate immune response against
these types of viruses.
“This way we would be able to fight the virus better and prevent serious consequences,”
Alberola-Ila said. “Right now there is no treatment at all, so we are hoping to take
a step toward that long-term.”