Health officials report record numbers of West Nile virus this year, 2,118 cases and 92 deaths as of Wednesday, a jump of 25% from last week.
Cases will continue "probably into October," said Lyle Petersen, director of the division of vector-borne infectious diseases at the Centers for Disease Control and Prevention. "This is the highest number of cases reported to CDC through the first week in September since West Nile virus was first detected in the United States."
There have been human cases in 44 states. The mosquito-borne disease is hitting Texas hardest, with 1,013 cases and 40 deaths - nine more than last week.
"2012 is now officially our worst year ever for West Nile disease,"
said David Lakey, commissioner of the Texas Department of State Health Services. The worst year before this was 2003, when Texas had 439 cases and 40 deaths, he said.
Seventy percent of cases are in Texas, South Dakota, Mississippi, Oklahoma, Michigan and Louisiana. Nearly 45% of cases have been reported from Texas, Petersen said.
Cases are especially bad this year in part because of the mild winter, early spring and hot summer, all of which are excellent conditions for breeding of the Culex mosquito that carries the virus.
Originally from Africa, West Nile virus first appeared in New York City in 1999 and since then has spread across the entire nation. It lives in birds. Mosquitoes bite infected birds, become infected themselves, then pass the virus along to humans when they feed on them.
Most people who become infected with West Nile virus have no symptoms. About 20% of people infected have fever, headache and body aches, nausea, vomiting and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. These symptoms can last a few days to several weeks.
About one of 150 infected people will develop a severe illness including high fever, headache, neck stiffness, disorientation, tremors, convulsions, muscle weakness, vision loss and paralysis. These symptoms may last several weeks, and neurological effects may be permanent, according to the CDC.
To avoid West Nile:
- Outdoors, use insect repellent containing an EPA-registered active ingredient.
- At dusk and dawn when mosquitoes are most active, stay indoors or use insect repellent and wear long sleeves and pants.
- Make sure you have good screens on your windows and doors.
- Empty standing water from flower pots and other areas, so mosquitoes can't breed. Change water in pet dishes and bird baths weekly.