A rabid beaver may have attacked two people at Loch Raven Reservoir last weekend, but area public health officials say there has been no increase in rabies infection rates among humans or animals.
"We're not seeing anything noticeable," said Gary Thompson, rabies coordinator for the Baltimore County Health Department.
Cases of human infection are extremely rare, with only a few reported each year nationwide, according to federal health experts. The last human death in Maryland was in 1976 when a bat bit someone, state health officials say.
Physicians and hospitals are required to report animal bites to county and state health departments. Rabid animals also must be reported.
Five Carroll County residents were given rabies shots in July and six so far this month, said Doris Hare, a nurse with the county Health Department. That's about average for the summer months, a relatively busy time because people spend more time outside and are more likely to encounter wildlife.
In Anne Arundel County, about 115 people are given rabies shots each year, said Elin Jones, a Health Department spokeswoman.
Infection rates among animals also are largely unchanged in recent years, officials say.
In Baltimore County, between 30 and 60 animals test positive for rabies each year, the vast majority family pets infected when they encounter a raccoon, Thompson said.
"For the most part, it's been holding steady," said Eric Willelm, program manager for the Bureau of Environmental Health in Harford County.
Willelm said that on average, about 200 animals are tested for rabies in Harford every year, and about 20 turn out to be infected.
Thompson said the rabid beaver was killed after it apparently attacked two people swimming illegally in the reservoir last weekend.
The first attack occurred Saturday when a 14-year-old boy was bitten. The next day, a woman was attacked less than a half-mile away. In that case, the victim's husband and a passing bicyclist jumped in the water, "wrestled the beaver" off and killed it with a rock, Thompson said.
The beaver, tested at a state Health Department lab, was likely bitten by a rabid raccoon, he said.
Thompson said the husband and his wife received rabies treatments. The bicyclist later called health officials - who had been searching for him - but after an interview, the agency determined he had not been exposed.
Rabid beavers have been known to attack people, officials said.
Several people were bitten by a beaver at Deer Creek in Rocks State Park in Harford County in August 2005. A captured beaver tested positive for rabies.
The federal Centers for Disease Control and Prevention gets about one report each year of a rabid beaver attacking someone, according to Jesse Blanton, an epidemiologist in the CDC's poxvirus and rabies branch.
There are two forms of rabies virus: paralytic rabies that stops the animal in its tracks, and furious rabies, which can cause infected animals to attack trees, mutilate themselves or experience symptoms such as the "classic dog foaming at the mouth," Blanton said.
There are usually about two or three cases of human infection a year, said Blanton, with bats causing almost all of them.
Thompson said the best ways to protect yourself is to steer clear of wildlife; keep pets up to date on rabies shots; and choose recreation sites wisely, avoiding swimming in prohibited areas.