Princeton’s Health Officer Jeffrey C. Grosser is warning residents, especially those in the Linden Lane area, to keep a safe distance if they discover bats inside their homes and to call the Princeton Police Department or the Animal Control Officer.

The warning comes after two bats taken from two homes on Linden Lane were tested at the New Jersey Public Health Laboratory. Residents contacted Animal Control Officer Mark Johnson who picked up the bats and took them to the laboratory for testing.

The Princeton Health Department received notification that the bats had tested positive for the rabies virus. The Health Department customarily receives notification from the state laboratory of all findings of rabies specimens.

According to a statement from the Department, the Linden Lane area has had a recent history over the past two years of rabies in its wild and stray animals. Last year a bat tested positive in the vicinity.

Mr. Grosser said that it was important for all Princeton residents to ensure that “their homes do not have openings” that might invite wild animals to take up residence inside. “Bats and raccoons are the two species of mammals that most often are infected with rabies,” he said, noting that while rabies in humans is rare in the United States, which usually sees just one or two human cases per year, the most common source of human rabies in the country is bats. “Among the 19 cases of rabies in humans from 1997 to 2006, 17 (90 percent) were associated with bats.”

If local residents discover a bat in their home, they should try to confine it to a single room or area of the home and contact the local police who will report the situation to the Animal Control Officer for response.

“It is imperative that they do not open a window and release the bat,” said Mr. Grosser. “In all instances of potential human exposure involving bats, the bat in question should be safely collected, if possible, and submitted for rabies diagnosis.”

The rabies virus attacks the nervous system and is fatal in humans without prompt treatment. The disease is spread when a rabid animal’s saliva contacts another animal or human through wounds in the skin, typically a bite.

After suspected exposure, prophylactic treatment should be given as soon as possible and consists of a dose of immune globulin and a series of five rabies vaccinations over a 28-day period. Current vaccinations are relatively painless and given as close to the injured area as possible.

If anyone is bitten, scratched, or otherwise comes into close contact with a bat, rabies post-exposure prophylaxis is recommended unless the bat is available for testing and found negative for the virus.

Princeton’s Bats

Bats are not uncommon in Princeton where some residents enjoy seeing them at dusk, often flying high with swallows. Last week, Richard and Karen Woodbridge, whose Prospect Avenue home backs up against Lake Carnegie, were disturbed to find one flying laps around their bedroom. “I grew up in Princeton at a time when it was quite usual to see snakes and box turtles around, and bats don’t bother me,” said Mr. Woodbridge. “In fact, we felt quite sorry for him but we’d rather he wasn’t in our bedroom.”

The Woodbridges took exactly the steps that Mr. Grosser advised above. They left the room, closed the door so that the bat couldn’t escape, and called the Princeton Police Department. Their letter to Police Chief Nick Sutter about the incident reports the actions of Patrol Officer Darwin “Bill” Kieffer and can be founding this week’s Mailbox.

Since the Woodbridges sent their letter, they have learned that, unlike the bats found on Linden Lane, “their bat” tested negative for rabies. “It looked like a healthy animal and was quite big with at least a six inch wing span. It took some effort to catch but we managed it and I was very impressed with the quick response of the Princeton Police Department,” said Mr. Woodbridge.

Bat-Proofing Tips

The Health Department, which cautions residents to keep a safe distance from all wild and stray animals, suggests the following bat-proofing tips.

At dusk, observe to see from where the bats are exiting your home — this is their principal entry point.

Once you know where they are entering your home, seal off all of the other openings and crevices greater than 3/8 inches.

To seal these areas, use 1/4 inch hardware cloth, fly screen, sheet metal, wood, caulking, expandable polyurethane foam, or fiberglass insulation.

To seal the principal entry point, wait until the evening when you are sure all of the bats have left. Don’t try to seal the principal entry point in June or July because bat babies are likely to be left inside.

Hang one-half inch bird netting about the opening with staples or duct tape, letting it extend, unattached at the bottom, to one foot below the opening. This will allow the bats to leave but not enter again. After several days the opening can be sealed.

Seal the openings between November 15 and March 15. Because most bats will have left for hibernation elsewhere, this is the ideal time to bat-proof a home

For anyone who is unable to carry out this work themselves, private companies such as some wildlife removal specialists, pest control and other contractors provide permanent bat exclusion services.

Residents are reminded to contact the Princeton Animal Control Officer/Princeton Police Department at (609) 921-2100 if they encounter a bat in their home, suspicious wildlife, or encounters between wild and domestic animals.

For more information on bats and rabies, please visit, www.cdc.gov/rabies/bats/index.html or www.princetonnj.gov/health/index.html.