West Nile Infections Remain High. How Alarmed Should You Be?

West Nile numbers continue to climb, but health officials say people shouldn't worry as long as they're taking precautions to avoid mosquito bites

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Health officials are calling this year one of the worst West Nile years on record in the U.S. As of Tuesday, 48 states had reported cases of the disease to the Centers for Disease Control and Prevention (CDC), for a total of 3,545 cases nationwide and 47 deaths. Seventy percent of the cases have occurred in eight states: Texas, Mississippi, South Dakota, Michigan, California, Louisiana, Oklahoma and Illinois.

Perhaps somewhat more concerning is that more than half of the reported cases have involved the severe, neuroinvasive form of the virus, which can potentially cause encephalitis or meningitis. Only about 1 in 150 people will come down with the severe form of the disease, however. These symptoms can include high fever, headache, stiffness, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. If you’re experiencing these symptoms, the CDC recommends seeing your doctor and seeking hospital treatment. Severe symptoms can last weeks and occasionally result in permanent neurological effects.

About 80% of people who contract West Nile virus don’t experience any symptoms at all, while 20% of infected people will develop West Nile fever. The fever is characterized by mild symptoms including headache, fatigue, body pain, skin rash and swollen lymph glands, which can last anywhere from a couple of days to a few weeks. There is no specific treatment for West Nile fever, but you can use standard methods to treat its symptoms. Although even healthy people can feel wiped out for a week, it won’t cause any serious health damage.

(MORE: 5 Things You Need to Know About West Nile Virus)

The CDC says it’s hard to predict how many more cases of West Nile virus will be seen this year, especially given the two- to three-week lag time between infection and onset of symptoms. But based on patterns of previous seasonal outbreaks, the mid-August peak season is behind us and infections should decrease in the next several weeks. The outlook may be better for northern state dwellers, however.

“It is quite clear that this seasonal trend we see is much more pronounced in northern states than the southern states,” says Dr. Jorge Parada, infectious disease specialist with Loyola University Medical Center and medical spokesperson for National Pest Management Association (NPMA). “Here, in Chicago, where the temperatures are low, we are not thinking about mosquitoes, but if you’re in the southern states, you will still see them. … As long as the mosquitoes are out and about, we can expect more cases.”

Parada says he sees no reason to expect a large drop-off in cases in areas that remain warm. “There will be some, but not like what we are going to see in the northern states,” he predicts.

Still, Dr. Christopher Perkins, medical director at the Dallas County Health and Human Services noted in an email to Healthland that Dallas County, Texas, has already experienced a significant decline in new cases of human infections in September. Health officials credit the drop to seasonal changes, environmental mosquito control measures and citizens protecting themselves.

(MORE: Everything Is Bigger in Texas, Including the West Nile Virus Outbreak)

Many questions surrounding the outbreak of the disease remain uncertain — like why the nation is seeing such a big spike in the first place (health officials speculate that the mild winter, followed by an early, rainy spring and a long, hot summer allowed more mosquitoes to survive and thrive) and when cases will cease — but  as long as you’re taking precautions to protect yourself, you shouldn’t stress too much about contracting the virus.

“If you’re out at noon in Texas, the odds of getting a mosquito bite are almost nil,” says Parada. “If it’s sunset and you’re having a BBQ with your friends, maybe wear a long sleeve shirt, get some DEET on or eat in a screened in area.”

According to Perkins, everyone is encouraged to continue using insect repellent, wear long sleeves shirts and pants and minimize outdoor activities when mosquitoes are most active, but there’s no need to change vacation plans to high-risk states. “Come and enjoy your visit in Texas,” she says.

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1 comments
Mark McCutchan
Mark McCutchan

"Only about 1 in 150 people will come down with the severe form of the disease, however".

Doesn't so bad, but one of my California friends from my college days died yesterday from West Nile disease. Her high fever lead to her organs shutting down, and then we lost her.

My family will start using bug repellent, that's for sure.