Louisiana's Health Department says a blood test found the state's first human case of West Nile virus this year in a St. Bernard Parish. That's true of 90 percent of all people infected with the virus. Those cases are found if they donate blood or have blood tested for another reason.

In total, about 10 percent will develop a flu-like fever and a very few will have dangerous infections of the nervous system. Last year, Louisiana recorded 12 human cases of the virus -- the least since tracking began in 2002. That first year was the worst, with 328 cases. Mosquitoes spread west nile virus.

State Epidemiologist Dr. Raoult Rah-ool ratard recommends that people should protect themselves against mosquitoes year-round.