IUP Experts on the Issues: Professor Tom Simmons on West Nile Virus in Pennsylvania, 2012

Posted on 9/12/2012 12:43:01 PM

It's a record year for mosquitoes carrying West Nile virus in Pennsylvania, says Tom Simmons, professor of environmental health in the Department of Biology.

There have already been 2,500 mosquito pools, considerably more than the 1,400 mosquito pools in 2011, which was a state record.


Raw video (10 min)

Available for comment:

Tom Simmons
(724) 840-4822

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Michelle Fryling
(724) 357-2302

A mosquito pool is defined as at least one insect testing positive for the virus out of a test batch of up to 100 mosquitoes per trap.

As of August 23, eight human cases of West Nile virus in Pennsylvania have been reported by state authorities.

Six cases of the virus in horses have been reported. Horses are particularly susceptible to the virus; generally, cats and dogs are not, Simmons said.

Pennsylvania has conducted testing of mosquitoes for the virus since 2000. The worst year for human deaths from the virus was 2003, when nine people died out of 236 reported cases.

Simmons has been part of state efforts to trap mosquitoes for study since 2005, and is currently studying water mite parasitism of mosquitoes in collaboration with the state Department of Environmental Protection. 

The disease is spread from the bite from a common female mosquito drawing blood from humans.

“This has been a bad year for the disease because it’s been a good year for mosquitoes and virus – we’ve had a very hot summer,” Simmons said. 

Human cases of the disease will probably peak in September, according to Simmons.

What should you do?

  • No need for panic. Although the virus is making news with 21 deaths in Texas, and people should be aware, the Centers for Disease Control note that about 80 percent of people infected won’t have symptoms. About 20 percent will have mild symptoms, including fever, headache, fatigue, body pain, skin rash, and swollen lymph glands for a couple for days or weeks. Only about 1 person in 150 will develop the most severe form of West Nile disease, which can include West Nile encephalitis or meningitis.
  • Use insect repellent containing DEET.
  • Maintain your yard so that mosquitoes aren’t attracted to it: keep brush trimmed; don’t have standing water in containers or other places, including children’s toys; and keep your gutters clear.
  • Human to human transmission can’t happen, so there's no need to worry about this.