By Wally Kennedy

wkennedy@joplinglobe.com

Another case of West Nile virus, the fifth this year, has surfaced in Joplin.

The probable case was cited Tuesday by the Joplin Health Department. Joplin has logged more cases of West Nile virus this year than in any year since the virus arrived in 2002 in the region.

Ryan Talken, spokesman for the department, said the new case is unlike the previous four in that a person younger than 50 has been infected by the mosquito-borne disease. All of the other cases involved people over 50, who tend to be more vulnerable because of weakened immune systems.

“The cases are still scattered all across town,” Talken said. “That makes sense. A mosquito can travel up to a mile from where they hatch from. When conditions are ripe, they are ripe across a broad region.”

Relief will come when the first hard frost hits the area, he said.

Karen Yates, spokeswoman for the Missouri Department of Health and Senior Services, said it is likely that Missouri will have more cases this year than it had last year, when 60 cases and five deaths were reported.

Yates said 10 cases have been reported in St. Louis County, 10 in Jackson County, eight in Boone County and about eight in the city of St. Louis.

Those areas, she said, are more populated than Joplin. In terms of cases per 100,000 people, the rate in Jasper County is high, she said.

So far, there has been one known fatality in Missouri this year. Another fatality is under investigation in St. Louis, Yates said.

In addition to targeting prevention measures to those over 50, the federal Centers for Disease Control and Prevention has targeted another high-risk group for infection, Yates said. Organ-transplant patients, who have suppressed immune systems, have been identified as being at high risk for serious infection.

Talken said 2007 has been a wetter year than normal, and that probably has influenced the relatively high number of identified cases. He said there also is a possibility that physicians are testing more for the virus when patients show flulike symptoms.

Two cases, including one fatality, have been reported this year in Ottawa County, Okla.

Late August through September is the peak season for the disease locally, health officials said.