Health officials, eager to learn more about Allegheny County's night life, are asking people to help identify watering holes and other gathering places known to be popular to denizens of the night -- raccoons, to be specific.

Those hot spots will go high on the list of areas that the county Health Department hopes to bait next month as its raccoon rabies vaccination program gets under way for its second year.

Health Department workers will be distributing the 100,000 vaccine-laced bricks of fish meal throughout the county during the week of Aug. 11 and the U.S. Department of Agriculture will use airplanes or helicopters later in the month to distribute additional bait over undeveloped and sparsely populated areas of the county and Western Pennsylvania at large.

It's part of a National Oral Rabies Vaccination Program mounted by the U.S. Department of Agriculture. That program already has halted the westward spread of rabies toward the Midwest and last year made Western Pennsylvania the front line in an attempt to eradicate the virus. All or parts of 11 western counties were baited in the first year of the program.

"One baiting will not solve the problem," noted Dennis Slate, national coordinator of the program, though the first year of baiting resulted in 25 percent to 30 percent of raccoons here already having detectable levels of immunity.

This year, 2 million baits -- an increase of 700,000 -- will be distributed by ground and by air in Pennsylvania, with the baited area expanded to include eastern Allegheny County and areas of other counties almost as far east as Indiana County, Slate said. Pittsburgh is the first major metropolitan area to be baited as part of the program.

Guillermo Cole, spokesman for the Allegheny County Health Department, said 11 rabid animals -- six of them raccoons -- had been reported this year in the county as of the end of June, compared with 20 animals, including 14 raccoons, during the same period last year.

"We're not reading too much into this," he cautioned. "We're certainly happy to see there's a decrease in rabid animals, but we're not prepared to link it to the vaccination program."

Just yesterday, the department confirmed rabies in its 12th animal this year -- a raccoon found in a North Side swimming pool. No human cases have been reported, though four cases earlier this year resulted in human exposure through a cut, bite or saliva from an infected animal.

For this year's baiting, the department is seeking advice from residents about places that raccoons congregate or are regularly seen. The county cannot bait private property, but will place a high priority on public areas identified by residents, Cole said. To report raccoon hangouts, call the department at 412-687-2243 or visit its Web site at www.achd.net. The department asks that the area be identified by municipality, the street name and block number or, in lieu of a street name or block number, a landmark or other reference point.

One early sign of success of the immunization program in Pennsylvania will be when Ohio feels confident enough to halt its 7-year-old raccoon vaccination program. That program has been successful in stopping the westward spread of rabies. The virus breached what was supposed to be a barrier -- the Appalachians -- in 1992 and reached Youngstown by 1996. Since 1999, two years after Ohio began its immunization program, the only rabies case in Ohio occurred recently in a hotspot along the Ohio-Pennsylvania border, Slate said.

The national vaccine program also extends south through West Virginia, Tennessee and, for the first time this year, into northwest Maryland.