The number of cases so far this year is the highest recorded since the disease was first detected in the United States in 1999. As of August 21, 38 states had reported human infections. The cases reported to the CDC total 1,118, including 41 deaths.
"The peak of West Nile virus epidemics usually occurs in mid-August, but it takes a couple of weeks for people to get sick, go to the doctor and get reported," said Dr. Lyle Petersen, the director of the CDC's Vector-Borne Infectious Disease Division. "Thus we expect many more cases to occur."
Petersen said that the reason for the high number of cases this year is unclear, but that unusually warm weather could have fostered favorable conditions for the disease's transfer to humans.
About 75 percent of the cases are in Texas, Mississippi, Louisiana, South Dakota and Oklahoma. Texas has been at the epicenter of the outbreak, with 586 confirmed cases and 21 deaths, according to the Texas Department of State Health Services.
Last Wednesday, the Indiana State Department of Health announced the state’s first death in 2012 due to the virus. A total of 10 statewide cases have been reported so far this year. Confirmed human cases have been found in Allen, Fulton, Hamilton, Hancock, Jackson, Monroe, Marion, Tippecanoe and Vanderburgh counties. Health officials said so far in 2012, mosquitoes carrying the virus have been found in 67 Indiana counties, compared with 34 counties in 2011.
“Nationally, we are being hit harder than ever before, especially in some of the southern states like Texas,” said State Health Commissioner Gregory Larkin, M.D. “Here in Indiana we are seeing more counties earlier in the year with positive mosquito pools, meaning a greater risk to Hoosiers. One of the most effective ways Hoosiers can protect themselves is to eliminate areas where mosquitoes breed. Dump wading pools, bird baths, buckets and be sure to clean your gutters and discard any debris in your yard.”
Health officials said those who spend time in wooded areas are not the only ones at risk for the mosquito-borne virus. They said a majority of people who became infected were working in the garden, mowing the lawn or just sitting outside on the porch.
Here are five things you need to know about West Nile virus:
1. Most mosquitoes do not carry West Nile.
In areas where mosquitoes carry the virus, only about one in 500 mosquitoes is infected, according to the Connecticut Mosquito Management Program.
2. Most people bit by West Nile mosquitoes do not get sick.
About 80 percent of people bit by a mosquito infected with the West Nile virus do not get sick, according to the CDC. About 20% will have relatively mild symptoms, such as fever, headache and vomiting. Symptoms can last for as short as a few days or as long as a few weeks. About one in 150 people infected with West Nile will develop a severe illness, which can include paralysis, coma or death.
3. You can help prevent West Nile with the "four Ds."
• Use mosquito repellent with DEET
• Dress in long pants and long sleeves
• Be especially careful at dusk and dawn
• Drain any standing water, such as kiddie pools or bird fountains, where mosquitoes like to breed.
4. People over 50 are most vulnerable.
Those older than 50 are the most likely to become severely ill with West Nile and should take special care to avoid mosquitoes, according to the CDC.
5. Seek medical care immediately if you have severe headaches or confusion.
If you develop symptoms of severe West Nile virus illness, such as unusually severe headaches or confusion, seek medical attention immediately, according to the CDC. Severe illness usually requires hospitalization. Milder cases improve on their own and do not necessarily require medical attention.
