ATLANTA (AP) — U.S. health officials on Wednesday reported an alarming increase in the number of West Nile cases reported so far this year, and one expert called it "one of the worst" outbreaks since the virus appeared in the country in 1999.
Three times the usual number of West Nile cases — 1,118 illnesses — have been reported so far, with 41 deaths.
About half of them have been in Texas, according to the Centers for Disease Control and Prevention. In an average year, fewer than 300 cases are reported this early.
"We're in the midst of one of the largest West Nile outbreaks ever seen in the United States," said Dr. Lyle Petersen, a CDC official.
Never before have so many illnesses been reported this early, said Petersen, who oversees the CDC's mosquito-borne illness programs.
Most infections are usually reported in August and September, so it's too early to say how bad this year will end up, CDC officials said.
They think the mild winter, early spring and very hot summer have fostered breeding of mosquitoes that pick up the virus from birds they bite and then spread it to people.
West Nile virus peaked in the U.S. in 2002 and 2003, when severe illnesses reached nearly 3,000 and deaths surpassed 260. Last year was mild, with fewer than 700 cases.
Only about one in five infected people get sick. One in 150 infected people will develop severe symptoms including neck stiffness, disorientation, coma and paralysis.