Thursday, June 12, 2008

Latest update on West Nile situation in North America

In Canada, no human cases or seropositive dead birds were reported so far this year. However, in the US, according to CDC and ProMedMail,  5 states (Arizona, Mississippi, Oklahoma, Tennessee and Texas) reported a total of 8 West Nile cases in humans up to the 10th of June 2008. Six of these cases were classified as West Nile fever while 2 were neuroinvasive. Fortunately, no fatalities occurred so far. On ArboNet, the most recent case appears to be in May 2008 (21st epidemiological week) in Texas. Additionally, Alabama reported an equine infection (March 2008, 10th epidemiological week), while California and South Carolina reported WN-positive dead birds (the latest confirmed cases on the 22nd and 18th week, respectively). California and Florida reported WN seroconversion in sentinel animals (5th and 12th week, respectively). West Nile-positive mosquito pools have been reported from California (21st week), Illinois (23rd week), Indiana (23rd week), Louisiana (23rd week) and Texas (22nd week).Weeks given are the latest week for which West Nile positive pools have been found for that state.  Louisiana had a total of 251 positive mosquito pools reported up to 9th June 2008.