PLEASANTON, Calif. (AP) --
Federal health officials are worried about a polio-like form of West Nile virus that has infected more than 30 people, including a California water skier who was bitten by an infected mosquito in Colorado last summer.
Researchers at the Centers for Disease Control and Prevention in Atlanta are monitoring the rare disease known as acute flaccid paralysis, or West Nile poliomyelitis, which struck down 32 residents last year in Colorado.
"Most of the people have a condition almost identical to that caused by the polio virus," CDC epidemiologist James Sejvar told the San Francisco Chronicle. "Those developing West Nile poliomyelitis tend to be younger and otherwise healthy."
The disease is carried by birds and transmitted to humans by mosquitoes. About 20 percent of those bitten by an infected insect show flu-like symptoms, while about one in 100 suffer the most severe form of the illness, developing life-threatening brain inflammation.
By contrast, the rare polio-like variant tends to strike healthy adults in their 30s and 40s. Doctors aren't sure if patients will ever recover full use of their limbs, and some patients can no longer breathe without a ventilator.
No cases of West Nile poliomyelitis have been confirmed in California, but researchers are looking into several suspicious cases. On Tuesday, state health authorities reported that in the past week the number of West Nile infections rose more than 46 percent to 277 cases, mostly in southern California. The disease has claimed nine lives in the state.
Richelle Matli, 48, of Pleasanton, contracted West Nile poliomyelitis through a mosquito bite last summer in Fort Collins, Colo., where she was competing in a water ski competition. She had hoped to ski in national competitions two weeks later, but ended up spending five days in intensive care at a San Francisco hospital with a polio-like paralysis in her left leg.
"I went into the hospital under my own power and came out in a wheelchair," said Matli, an X-ray technician with two teenage daughters. Before the illness, she was ranked 5th nationally in the slalom competition, which requires a skier to weave through buoys on a single ski.
"There was a time when I could not lift my foot," Matli said. "A month ago, I still could not walk up a stair. I still can't stand on my toes. But I see little improvements almost everyday."
©2004 Associated Press