Aug 5, 2004 (CIDRAP News) The number of West Nile virus cases reported in the United States this year jumped more than 50% with the addition of 141 cases between Jul 28 and Aug 3, according to the Centers for Disease Control and Prevention (CDC).
The CDC said the cases reported by states last week increased the total for the year from 265 to 406. More than half of the cases247have been in Arizona. California ranks second with 69 cases and Colorado is third with 44, according to the Aug 6 Morbidity and Mortality Weekly Report. Seven people have died of the illness this year.
About 38% of the cases reported to the CDC this year (156 of 406) have been severe, involving meningitis, encephalitis, or myelitis, the agency says. Last year about 28% of the reported cases were in this category. (However, the CDC estimates that only about 20% of people infected with West Nile actually become ill and fewer than 1% have neurologic involvement.)
The report says evidence of West Nile infection has been found in donated blood from 38 people this year, including 31 from Arizona. Nine of these blood donors later became ill with West Nile symptoms.
The number of West Nile cases so far this year is somewhat ahead of last year's tally at this point. By Aug 6, 2003, 153 cases had been reported to the CDC, including 109 cases in the week of Jul 31 through Aug 6.
CDC. West Nile virus activityUnited States, July 28-August 3, 2004. MMWR 2004;53(30):686-7
MMWR West Nile report for Jul 31 to Aug 6, 2003