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2012 was second worst year for West Nile Virus

Category: Infectious Diseases

The Centers for Disease Control (CDC) reported that as of Oct. 16, there have been 4,531 human cases of West Nile virus (WNV) reported, reaching a death toll of 183, making this year's outbreak the second worst in six years. Of all the WNV cases, 51 percent were classified as being neuroinvasive diseases, such as meningitis or encephalitis, while 49 percent were non-neuroinvasive.

In total, 48 states have reported the infection in people or animals and nearly 70 percent of all the cases have come from eight states: Texas, California, Louisiana, Mississippi, Illinois, South Dakota, Michigan and Oklahoma, and nearly a third of the cases can be attributed to Texas.

Erin Staples of the CDC told USA Today that this week alone there have been 282 cases and 15 WNV-related deaths reported, which is an 8 percent increase from the previous week. This doesn't necessarily indicate a rise in mosquito activity, rather there is a delay between the WNV getting reported and the state health department notifying the CDC.

According to the news source, the disease rate climaxed in late August when it increased by nearly 35 percent every week.

With the onset of colder temperatures, rates of WNV are expected to steadily decline.

"As the cold weather sets in, particularly in the north and then moving south, that will stop the mosquito activity and then decrease the number of cases," Staples said.

West Nile Virus Symptoms
The CDC reports that only 1 in every 150 people who contract WNV, which can be detected with a lab test, will get severely sick. Some symptoms include fever, headache, stiff neck, disorientation, confusion, muscle weakness, convulsions, vision loss, numbness, and in some cases, paralysis. Less serious symptoms are swollen lymph glands or a rash on the chest. While milder symptoms usually remain for only a couple of days, some people will show signs of sickness for up to several weeks. Nearly 80 percent of people who get infected with WNV, won't show any symptoms.

Reason for spreading
According to the CDC, WNV is spread through infected mosquitoes. The insects get the disease when they bite an infected bird. A small portion of WNV infection comes from blood transfusions, transplants as well as breastfeeding, but it can't be spread via human contact.

Prevention
Some methods of prevention that the CDC recommends include using insect repellent or wearing long sleeves when going outside, especially at dusk and dawn, which is when mosquito activity is the highest. You should also have effective screens on doors and windows to prevent mosquitoes from entering your home.