West Nile cases may reach 1,000

Maryland among states reporting the disease

August 22, 2002|By Lawrence K. Altman | Lawrence K. Altman,NEW YORK TIMES NEWS SERVICE

The number of cases of West Nile fever is expected to rise sharply in the next week and could eventually reach 1,000, federal health officials say. If the current epidemic reflects experience, about 10 percent of the cases will be fatal.

West Nile first appeared in the United States in 1999, when seven people infected with it in New York died.

Nationwide, the CDC has reported 12 U.S. deaths this year from West Nile, eight of them in Louisiana. As of Tuesday, 253 human cases of the virus had been reported to the CDC this year in 11 states and the District of Columbia.

The disease first appeared this year on the East Coast, but quickly spread west. Officials in Missouri, Kentucky and Texas have confirmed that they are investigating three deaths suspected of being caused by the virus. Maryland is among the states with confirmed or suspected cases in the nation's worst outbreak of the mosquito-borne disease.

Dr. Lyle R. Petersen, an official with the federal Centers for Disease Control and Prevention, said the agency did not have detailed information on the severity of the illnesses. But he said a vast majority were hospitalized with brain inflammation from meningitis or encephalitis.

"We can expect more cases, and potentially a lot more cases," said Petersen, an epidemiologist who specializes in insect-borne diseases. "We don't know where the peak will be."

The CDC has sent at least 20 scientists to the affected states, Petersen said, adding that they had made important preliminary findings. But he declined to discuss the findings, calling them "preliminary results that may not be correct."

Beyond the sheer number of cases, health officials are concerned about the timing. In previous years, only 10 percent to 15 percent of West Nile patients had symptoms before Aug. 1; the peak time for onset of symptoms was the last week of August and the first week of September. But so far this year, Petersen said, the onset of symptoms in a vast majority of cases came in July, suggesting that the peak probably lies ahead.

Petersen, who said state and local mosquito control measures had probably prevented many cases and would have "a major effect in blunting this epidemic."

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