LOUISIANA — The Louisiana Department of Health and Hospitals (DHH) has confirmed five new West Nile virus cases this week, bringing this year's total number of cases to 39. This week's new infections include three cases of neuroinvasive disease, with one case each from Caldwell, Lafayette and Rapides parishes, one case of West Nile fever from Ouchita Parish and one asymptomatic case from Lafayette Parish.
Humans contract West Nile when they are bitten by mosquitoes infected with the virus. When people are infected with West Nile, the virus will affect them one of three ways. West Nile neuroinvasive disease is the most serious type, infecting the brain and spinal cord. Neuroinvasive disease can lead to death, paralysis and brain damage. The milder viral infection is West Nile fever, in which people experience flu-like symptoms. The majority of people who contract West Nile will be asymptomatic, which means they show no symptoms. These cases are typically detected through blood donations or in the course of other routine medical tests.
About 90 percent of all cases are asymptomatic, while about 10 percent will develop West Nile fever. Only a very small number of infected individuals will show the serious symptoms associated with the neuroinvasive disease. Residents who are 65 years old and older are at higher risk for complications, but everyone is at risk for infection.
Last year, Louisiana reported 160 cases of West Nile virus neuroinvasive disease in the state, which is down from 2002's high of 204 cases of West Nile virus neuroinvasive disease. DHH has been tracking West Nile virus for more than a decade, and statistics about its occurrence in Louisiana can be found in DHH's weekly Arbovirus Surveillance Report, found on line at www.dhh.louisiana.gov/fightthebite.
This year, Ouachita Parish has reported 10 cases of neuroinvasive disease, one of which was previously reported as West Nile fever and has been upgraded to neuroinvasive disease. Lafayette Parish has five cases, two of which were previously reported as West Nile fever and have been upgraded to neuroinvasive disease. Caldwell and Rapides parishes each have three neuroinvasive disease cases, and Calcasieu, Livingston and St. Tammany parishes each have one case of neuroinvasive disease. The state has reported one West Nile virus death so far this year.