The West Nile virus season this year appears to be the mildest in seven years, with less than a third the number of serious cases as last year's total, U.S. health officials say.
Preliminary reports show there were 368 severe cases, with 18 deaths. Mississippi and California were hardest hit, accounting for nearly half the cases. Putnam County has had no reported cases of the virus in humans.
"We have had one crow test positive for West Nile," said Putnam County Board of Health Public Health Coordinator and Environmental Health Specialist Doug Ehmen.
"I think there are only two cases of humans having the virus in the state. The people most at risk are the elderly. Most people who get the virus wouldn't even realize they have it. They just have some flu-like symptoms," said Ehmen.
The only counties reporting human cases of West Nile were Perry and Tippecanoe with one case each.
Most West Nile infections are reported in August and September, so health officials are hopeful the season will remain mild.
Officials at the Centers for Disease Control and Prevention (CDC) are not sure why it has been so mild. It's the fewest cases since 2001, when the mosquito-borne virus was still emerging in the United States and was only reported in 10 states.
Mosquitoes often pick up the virus from birds they bite and then spread it to people. Perhaps the weather in some areas of the country was not as favorable for mosquito breeding as in years past, some experts said.
West Nile virus was first reported in the United States in 1999 in New York. It gradually spread across the country.
About one in five infected people get sick. One in 150 will develop severe symptoms including neck stiffness, disorientation, coma and paralysis.
For all of 2007, more than 1,200 cases of severe West Nile illness were reported, and 124 deaths. The peaks occurred in 2002 and 2003, when severe illnesses numbered nearly 3,000 and deaths surpassed 260.
Less than 1 percent of people who are bitten and infected with the West Nile Virus become seriously ill. The most serious complication is encephalitis, an infection of the central nervous system. Symptoms of encephalitis include fever, severe headache, stiff neck, and changes in mental status (disorientation).
For more information on the West Nile virus, call the Putnam County Board of Health at 653-5210 or go to their Web site at www.co.putnam.in.us/healthdepartment.