The city of East Grand Rapids is taking preventative measures against the West Nile virus by placing pellets throughout the area designed to kill mosquito larvae.

The city's action is coming after recent mosquito trap monitoring by the Kent County Health Department found an unusually high number of mosquitoes testing positive for West Nile virus.

There have been no human cases reported in Kent County yet this year, but the tests led health experts at the County Health Department to believe that a rise in human cases is possible.

East Grand Rapids has placed biological larvicide pellets into all of the city catch basins and storm water retention areas.

Larvicide kills mosquito larvae in breeding habitats and the pellets placed within the city contain Bacillus sphaericus, a naturally occurring bacterium used to kill mosquito larvae, said Assistant City Manager Doug LaFave.

"Mosquito larvae ingest the bacteria, which then disrupts the mosquito larvae internally by binding to receptor cells present in insects but not in mammals or other wildlife," LaFave said.

The first confirmed case of West Nile virus infecting a human in Kent County occurred in 2004. The victim, a 13-year-old boy, recovered from the virus, according to the County Health Department.

While most people infected with the virus will have no symptoms, up to 20 percent may develop mild illness and one in 150 people infected will develop severe illness, which can be fatal.

The city is recommending that residents visit the Health Department's webpage to learn more about mosquitoes and West Nile and what they can do to prevent and reduce exposure at www.accesskent.com.

East Grand Rapids also has informational pamphlets provided by the KCHD available the lobby of the city's Community Center, 746 Lakeside Drive SE.