BOSTON - Gripped by fear of the potentially fatal West Nile virus, some people in the Northeast are asking health officials to test everything from a dead bat in a toilet to birds that were shot to death or mauled by the family cat.
Although health officials don't want to minimize the public's concern about the virus, they emphasize that the real West Nile threat to humans comes from mosquitoes - not birds or bats.
''You should not worry about having a dead crow in your backyard. You should be worried about having mosquitoes in your backyard,'' Kevin J. McGowan, curator and senior research associate at the Cornell University Museum of Vertebrates, said Monday.
The virus killed seven people and sickened more than 60 in the New York City area last year, its first appearance in the Western Hemisphere.
No human deaths have been reported this year, but mosquitoes carrying the virus have been found in parts of New York, and the virus has shown up in birds there and elsewhere in the Northeast.
Since two crows tested positive in Massachusetts last week - the first time the virus had been detected in the state - officials have been asked to test hundreds of other birds, including one killed by a family cat.
Testing on two birds in Maine was called off after it was determined that they had been shot to death. Boston officials told one man curious about the health of a dead bat in his toilet to ''get rid of it or flush it,'' said Steve Crosby, director of the city's animal control.
''People's risk is very, very low,'' said Valerie Bassett of the Boston Health Department. ''Certainly people shouldn't be afraid, but we want to make sure they know the precautions people could take.''
The virus is fatal in only a few people who contract it. The West Nile virus can cause encephalitis, a dangerous swelling of the brain that can be deadly. Most who contract it experience flulike symptoms and never realize they have been exposed to the virus.
Officials have launched an extensive effort in the Northeast to inform the public and kill mosquitoes carrying the virus, which has also been found in New Jersey, Connecticut and Maryland. Officials have sprayed pesticides throughout New York City, including Central Park.
New York's Orange County plans to drop larvicide to kill mosquito eggs in all the county's 20,000 municipal storm drains and to distribute about 30,000 containers of free insect repellent through local pharmacies.
Those efforts to control mosquitoes are in turn creating other fears - that the pesticides are harmful.
A group of Long Island Sound lobstermen contend that pesticide is killing millions of lobsters. So far, there is no definitive proof of their claim. But the Western Long Island Sound Lobster Association has hired researchers to investigate if the pesticides caused the number of lobsters caught to drop more than 50 percent in 1999.
The Department of Wildlife in Massachusetts also voiced concerns that pesticide spraying on a pond could harm the freshwater three-spine stickleback, one of nine endangered or threatened species of fish in the state.
Public service announcements will be shown in 185 movie theaters in 11 at-risk counties in New York to educate people about the virus.
Health officials in Massachusetts are attempting to keep residents calm while advising them to use insect repellent, to wear socks, shoes and long-sleeved shirts, and to remove sources of standing water around their homes.
''I was driving past marshlands yesterday and it crossed my mind, but then I didn't think any more about it,'' Jim Mulcahy of Boston said Monday. ''I wouldn't go walking through those marshlands, though.''
