The threat of West Nile virus: Facts, stats & prevention


Related Articles

As if the humidity and sweatiness of this summer weren’t enough, we can now add West Nile to the list. Government health officials and the National Pest Management Association experts are warning that this mosquito season may pose a severe public health threat.

According to the Centers for Disease Control and Prevention, so far 43 states have reported West Nile virus (WNV) infections in people, birds or mosquitoes, as of Aug. 14. A total of 693 cases of WNV in people, including 26 deaths, have been reported. Of these, 406 (59%) were classified as neuroinvasive disease — such as meningitis or encephalitis — and 287 (41%) were classified as non-neuroinvasive disease.

The 693 reported cases, thus far, is the highest number of West Nile virus cases reported to the CDC through the second week in August since West Nile virus was first detected in the United States in 1999. More than 80% of the cases have been reported from six states — Texas, Mississippi, Louisiana, Oklahoma, South Dakota and California — and almost half of all cases have been reported from Texas.

(Update: The CDC has reported that as of Aug. 21, 47 states have reported WNV infections. A total of 1,118 cases in people, including 41 deaths, have been reported. Of these, 629 (56%) were classified as neuroinvasive disease and 489 (44%) were classified as non-neuroinvasive disease.)

Click here for WNV updates from the CDC.

It's gotten so bad in Texas that the city of Fort Worth has announced that it will hold do-it-yourself help sessions for dealing with mosquitoes and the threat of West Nile virus at a number of Home Depot and Lowe’s locations.

”In addition to protecting oneself, NPMA is asking the public to help by limiting the number of mosquito breeding grounds around their homes. Mosquitoes can breed in as little as half an inch of water, so it’s important to take stock of any items that may collect water after a rainfall, such as flowerpots, children’s pools and toys, grill covers and others,” said Missy Henriksen, VP public affairs for NPMA.

According to Jorge Parada, medical spokesman for the NPMA, most cases of WNV result in a mild infection with only minor symptoms, which can go unnoticed or feel like a summer flu. However, he added, “In extreme cases, it can be a potentially life-threatening infection with higher fever, head and body aches, worsening weakness, confusion and even coma. Anyone experiencing these symptoms should seek immediate medical attention.”

So without further ado, we present some basic facts about WNV to help you protect yourself this summer.

What is WNV?
According to the CDC, WNV is a seasonal epidemic in North America that flares up in the summer and continues into the fall.

How can I prevent WNV?
There are community-based mosquito control programs that can reduce vector populations. But on a personal level, make sure you:

• Use insect repellent outdoors with an EPA-registered active ingredient.
• Many mosquitoes are most active at dusk and dawn. Wear long sleeves and pants or stay inside during these hours.
• Install good screens on your windows and doors.
• Remove mosquito breeding sites — empty standing water from flower pots, buckets and barrels; change the water in pet dishes and replace the water in bird baths weekly; drill holes in tire swings so water drains out; and keep children's wading pools empty and on their sides when they aren't being used.

What are the symptoms?
About one in 150 people will develop severe illness. Symptoms include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis.

Up to 20% of people have symptoms such as fever, headache, body aches, nausea, vomiting, sometimes swollen lymph glands or a skin rash on the chest, stomach and back.

About 80% of people will not show any symptoms at all.

How soon do people get sick?
Symptoms will develop between three and 14 days once bitten.

What are the chances of getting sick from WNV?
• If you’re older than 50, you are more likely to develop serious symptoms of WNV.
• If you’re outside often, you increase your chances.
• If you need a medical procedure, your risk is very low. All donated blood is checked for WNV before being used.

Click here for more information regarding WNV from the CDC, and here for five common myths.