Local officials are concerned about a "hot spot" in Lancaster Township where in recent weeks mosquitoes infected with West Nile virus have apparently caused the death or sickness of at least five hawks.
Rain prevented officials Monday night from spraying a 400-square-foot intermittent pond and the surrounding area in a populated area near the intersection of Millersville Pike and Schoolhouse Road.
They planned to try again Tuesday night.
Twice in recent weeks, adult mosquitoes near the wet spot tested positive for West Nile virus.
No human cases of the occasionally fatal West Nile virus have been found so far in Pennsylvania, but a high number of mosquitoes carrying the virus this early in the summer has officials here and in southeastern Pennsylvania on alert.
Lancaster, along with Delaware, Montgomery, Bucks and Philadelphia, are so far the only counties in Pennsylvania where mosquitoes infected with the virus have been found.
"The variables are lining up," said Matt Mercer, Lancaster County's West Nile virus coordinator. "We had large amounts of standing water in May and June. A good spell of hot weather increases activity. The (mosquito) population has just ballooned. The population has exploded."
Mercer said his office could not spray traditional hot spots in the county before larva hatched.
Hampering those efforts was a 26 percent cut in the local West Nile virus program this year by the state.
Also troubling are the five hawks found dead or acting oddly in the area.
A red-tailed hawk was found July 4 on the Bean Hill Road property of Daniel and Laura Knarr. It died the next day.
Laura Knarr, aware that West Nile virus had been found in the area, contacted officials who retrieved the bird. A state Department of Agriculture lab confirmed the juvenile hawk died of West Nile virus after it had been bitten by an infected mosquito.
A dead red-tailed hawk found by a resident near the intersection of Betz Farm Road and Gable Park Road was too decomposed to test.
Another resident approached within 10 feet of a hawk sitting on a gazebo in the Hershey Heritage apartment complex off Wabank Road on July 8.
And the local Organization for the Responsible Care of Animals recently removed two sick hawks from the Wabank Road area. One died and the other was still alive as of last Friday while being cared for by a licensed wildlife rehabilitator in York County.
A dead crow also was recently found in the area.
Birds of prey, along with crows and blue jays, are particularly susceptible to West Nile virus. They get the disease after being bitten by an infected mosquito.
Anyone finding a dead bird belonging to one of those species — it needs to have been dead for no more than 48 hours — is asked to call Mercer at 394-6851.
When the Lancaster Township hot spot was identified, perimeter traps were set for mosquitoes within a one-mile radius to try to determine if infected mosquitoes had spread to a larger area.
Traps set in Lancaster city at Buchanan Park, St. Joseph's Cemetery and Christ Lutheran Church on West King Street did not turn up adult mosquitoes with the virus.
Mercer hopes that means infected mosquitoes are in a relatively confined area.
"The whole thing boils down to spraying that generation and trying to nip the activity in the bud," Mercer said.
Other infected mosquitoes were found in Manheim and East Hempfield townships. Both of those areas have been sprayed with a low-impact insecticide.
Only certain species of mosquitoes carry the virus. The chances of a person being bitten by an infected mosquito is relatively small. Even then, most people will not be affected by the virus or develop flu-like symptoms.
But in the elderly and other people with weakened immune systems the virus can turn into encephalitis, an infection that swells the brain. The virus can kill horses and mules that are not vaccinated.
No humans or livestock were known to have contracted the virus in Lancaster County in 2009. But the number of samples with infected mosquitoes rose from 10 in 2009 to 33 last year. They were found in 17 different municipalities.
The worst year for West Nile in Lancaster County was in 2003, when 37 people here contracted the disease and two people died. At least 167 horses and mules died.
For more on West Nile virus in Pennsylvania, go to
www.westnile.state.pa.us.
acrable@lnpnews.com
This juvenile red-tailed hawk was photographed in a shallow pond off Bean Hill Road on July 4. It died a day later, and a state lab confirmed it died from West Nile virus.
