In May, rain fell in buckets, leaving area lakes, rivers and fields overflowing. With the increased volume of standing water, many also anticipate a record crop of mosquitoes.
But does a higher population escalate the risk for mosquito-borne diseases, particularly West Nile Virus?
OMRF 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,” said Kovats. “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, said Alberola-Ila, 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 just a few days to several weeks. Those with the more severe form often require hospitalization.
Mosquitoes can transmit anywhere from 10,000 to one million viruses in a single bite, said Kovats. “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 Oklahoma 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 eventually 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 one 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 non-fatal cases and 15 deaths. There were 76 non-fatal 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 already suffering from compromised immune systems. Even though your odds of contracting a serious form of the virus are slim, it is still best to remember insect repellant on your way to any outdoor activities in the coming months.
“I don’t think there should be any panic factor,” said Kovats. “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.”
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,” said Kovats. “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 an individual 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,” said Alberola-Ila. “Right now there is no treatment at all, so we are hoping to take a step toward that long term.”
