Health department: Mosquitoes near floodwaters likely not carrying diseases

JEFFERSON CITY, Mo. -- Midwesterners watching swollen rivers and flooded fields can expect a mosquito bombardment, but a Missouri health department veterinarian said Thursday that the insects aren't likely to bring disease with them.

Missouri public health veterinarian Howard Pue said the mosquito species most likely to breed in the floodwaters are "nuisance" species that leave the familiar welts and itchy bites but cannot spread the potentially deadly West Nile virus or St. Louis encephalitis.

"The breed in that habitat are a nuisance, but not normally the vector for disease," Pue said.

A mosquito picks up West Nile or St. Louis encephalitis often by biting an infected bird and can then spread it by biting a person. The mosquito isn't itself sickened by the disease.

According to the Missouri Health Surveillance Information System, Missouri had 444 reported cases of West Nile, including 30 deaths, from 2002 to 2007.

Pue said that in a couple of weeks, the eggs laid by northeast Missouri's mosquitoes will start hatching, just in time to greet people cleaning up after the flooding. But he said they probably won't make people sick.

"The females will be a nuisance and discomfort for the people going there," he said.

But there's more than just mosquito-borne diseases that can come with floodwaters. There's also risk from farm animal waste runoff and overflowing sewer and drainage systems that can send untreated human sewage and industrial waste flowing down river, containing bacteria, viruses and parasites that each can make people sick.

Discussion about the potential for mosquito-borne diseases comes as the Missouri Department of Health and Senior Services is warning that state cases of West Nile and tick-borne diseases have been on the rise over the last two years.

State health department figures show that West Nile cases in Missouri declined annually from a 2002 high of 168, including seven deaths, to 30 cases, including two deaths, in 2005. Last year, the state had 77 cases, including five deaths.

For tick-borne illnesses such as Lyme disease and Rocky Mountain spotted fever, Missouri has had a total of 1,735 cases, including eight deaths, from 2002-2007. But last year alone, Missouri had 582 cases, including five deaths.

Health officials said that means it's especially important for Missourians to take precautions. They recommend: using insect repellant, eliminating pools of standing water near homes, wearing long sleeves and pants when possible, trying to stay indoors around dusk and dawn when mosquitoes are most active, and checking for ticks after walking through high grass. Warding off ticks requires insect repellants with 20 percent to 50 percent DEET.

Tom Austin, of Columbia, still has some lingering effects after getting ill from West Nile two years ago. Austin ended up with both meningitis and encephalitis, suffered nerve damage and became weak from lying in hospital beds.

"Take care when you're outside. This is something you don't want to get," he said. "It's kind of nasty."