Archive for Thursday, October 3, 2002

First case of West Nile virus confirmed in De Soto

October 3, 2002

The first incidence of West Nile virus in De Soto has been confirmed.

Local veterinarian Matthew VanderVelde said he tentatively diagnosed a horse with the virus after treating the animal Sept. 21. Kansas State University confirmed the diagnosis Sept. 24 through blood samples.

The 25-year-old Tennessee walking horse had to be destroyed, VanderVelde said. He has treated another horse in west Lenexa with the virus. That younger animal is recovering, he said.

"We are recommending people get their horses vaccinated this year," he said. "Some people are thinking they can wait until next spring, but the mosquito season will last until November."

The vaccine regimen starts with one shot, which requires a booster in three to six weeks. After that, annual vaccines are required, VanderVelde said. Each shot cost $20, he said.

The West Nile virus has spread across the United States and through Kansas at an amazing rate, VanderVelde said.

"It's been reported in 70 counties in Kansas," he said. "Meriden had 12 diagnosed cases. They saved only two horses."

That death rate was high, VanderVelde said. The virus has the potential of killing 40 percent of infected horses, he said.

The disease attacks the brain, spinal cord and central nervous system, VanderVelde said. The horse he put down suffered paralysis in its hind legs, facial twitching and uncontrollable chewing, he said.

It was only a matter of time before Kansas and Johnson County have a confirmed case of human infection, said Jose Izaquirre, contagious disease investigator with the Johnson County Health Department. It is almost certain local residents have been infected but were strong enough to fight off the virus.

"Eighty percent won't have any symptoms," he said. "Less than 1 percent have encephalitis.

"It's mostly a concern for the vulnerable the elderly or those individuals with medical problems that makes them susceptible."

To reduce the risk of infection, the health department is recommending people:

Avoid mosquito infested areas and stay inside during peak mosquito feeding hours (dusk to dawn).

Wear shoes, socks, long pants and a long-sleeved shirt when outdoors for long periods of time, especially from dusk to dawn.

Wear light colored clothing.

Use mosquito repellent when outdoors, following the manufacturer's directions.

Make sure all windows and doors have screens in good repair. Keep screens or windows closed.

Install yellow light bulbs in outdoor lamps. Unlike white bulbs, they won't attract mosquitoes.

Avoid scented antiperspirants, perfumes and colognes if outdoors. They attract mosquitoes and other insects.

Izaquirre said there were many unanswered questions about the virus, such as how much a viral load is required to infect humans. It could be that humans have to be bitten "a bunch" before they become invected.

Genetic signs of West Nile virus were found last week in the breast milk of a new mother battling the infection. Izaquirre said the Michigan woman's baby was not infected after 21 days of breast feeding, despite a human incubation period of six to 17 days.

The National Center for Disease Control is leaving decision on breast feeding in such cases to the mothers and their doctors. His office takes its cue from the CDC on all guidelines regarding the virus, Izaquirre said.

"When we come up with a statement, it needs to be backed up by science," he said. "We can't answer all the questions. There's a lot we don't know."

For example, it is assumed that once infected humans develop a lifelong immunity to the virus. But Izaquirre said that hasn't been scientifically confirmed. And although dogs and cats appear to be immune to consequences from the virus, it is not known if they are carriers, he said.

The virus does not affect cattle either, VanderVelde said. The virus was first identified in Uganda in 1937. It was first diagnosed in the United States in 1999 and 2000, when it infected residents in the New York City metropolitan area, New Jersey, and Connecticut.

"It think it's a disease that's here to stay for some time," VanderVelde said.

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