Rabies Detected in Keen’s Myotis Bat – Prince of Wales Island, Alaska

On July 13, biologists working on Prince of Wales Island trapped several Keen’s myotis bats near Harris River. One bat that appeared to be potentially ill and was acting more aggressively than the others was later euthanized and submitted to the Alaska State Virology Laboratory (ASVL) for rabies testing. This bat tested positive for rabies on July 17 and is only the third bat ever found to have rabies in Alaska.

There are several objectives for this Health Advisory:

1. To update what is known about bat rabies occurrence in Alaska;
2. To reinforce that people bitten by or exposed to bats should be evaluated promptly for possible rabies post-exposure prophylaxis; and
3. To encourage people finding sick or dead bats to contact wildlife and/or health authorities.

Prior bat rabies cases in Alaska

Six species of bats live in Alaska. Prior to July 2014, only two bats had been confirmed with rabies in Alaska. In 1993, a little brown bat found near Ketchikan in the Tongass Forest tested positive for rabies; the Centers for Disease Control and Prevention (CDC) characterized the virus strain as a silver-haired bat rabies virus variant. In 2006, a Keen’s myotis bat from northeastern Prince of Wales Island tested positive; that strain was characterized as a red bat rabies virus variant. There have been no cases of bat variant rabies among non-bats in Alaska.

In general, migratory patterns of bats in Alaska are not well-documented. It is reasonable to assume that rabies circulates among bat populations in southeastern Alaska, although we cannot exclude the possibility that any of the rabies-infected bats originated from outside Alaska. Bats from other regions in Alaska, including the Kenai Peninsula and the Anchorage-Mat-Su Valley area, have all tested negative for rabies. Samples from this third rabid bat will be sent to CDC for rabies virus variant characterization.

Potential bat exposures

Anyone who may have been bitten or scratched by a bat should contact a health care provider immediately to be evaluated for rabies post-exposure prophylaxis. If the bat is still available, it should be submitted to ASVL for rabies testing. Health care providers can contact the Alaska Section of Epidemiology (SOE) for assistance with rabies exposure consultations and for routing bats to ASVL for rabies testing. Call Epidemiology at 907-269-8000 M-F 8AM-5PM, or 800-478-0084 after hours.

Search for Children Playing with Rabid Bat

Children Playing With Rabid Bat

In New York's Tompkins County, Health Officials are still looking for 3 children who were playing with a rabid bat on [30 Jun 2014] in Dryden. The 3 kids were seen playing with the bat at Montgomery Park between 1:30 and 2:30 pm. The children are described as being a girl, about 7 or 8-years-old and 2 younger boys.The health department says it is imperative that they find the children so they can test them for rabies.Anyone with information about the identity of the 3 children should call 315-274-6688.

While the media report mentions the children will be "checked" for rabies, what will be check for is the need for post exposure prophylaxis. The Advisory Committee on Immunization Practices (ACIP) recommendations on Rabies vaccination is very detailed vis a vis exposures to bats:

"The most common rabies virus variants responsible for human rabies in the United States are bat-related; therefore, any potential exposure to a bat requires a thorough evaluation. If possible, bats involved in potential human exposures should be safely collected and submitted for rabies diagnosis.....

"The risk for rabies resulting from an encounter with a bat might be difficult to determine because of the limited injury inflicted by a bat bite (compared with more obvious wounds caused by the bite of terrestrial carnivores), an inaccurate recall of a bat encounter that might have occurred several weeks or months earlier, and evidence that some bat-related rabies viruses might be more likely to result in infection after inoculation into superficial epidermal layers.

For these reasons, any direct contact between a human and a bat should be evaluated for an exposure. If the person can be reasonably certain a bite, scratch, or mucous membrane exposure did not occur, or if the bat is available for testing and is negative for presence of rabies virus, postexposure prophylaxis is not necessary. Other situations that might qualify as exposures include finding a bat in the same room as a person who might be unaware that a bite or direct contact had occurred (e.g., a deeply sleeping person awakens to find a bat in the room or an adult witnesses a bat in the room with a previously unattended child, mentally disabled person, or intoxicated person). These situations should not be considered exposures if rabies is ruled out by diagnostic testing of the bat, or circumstances suggest it is unlikely that an exposure took place. Other household members who did not have direct contact with the bat or were awake and aware when in the same room as the bat should not be considered as having been exposed to rabies.

Circumstances that make it less likely that an undetected exposure occurred include the observation of bats roosting or flying in a room open to the outdoors, the observation of bats outdoors or in a setting where bats might normally be present, or situations in which the use of protective covers (e.g., mosquito netting) would reasonably be expected to preclude unnoticed contact. Because of the complexity of some of these situations, consultation with state and local health departments should always be sought. If necessary, further guidance can be sought from CDC and experts in bat ecology.

"During 1990--2007, a total of 34 naturally acquired bat-associated human cases of rabies was reported in the United States. In six cases, a bite was reported; in two cases, contact with a bat and a probable bite were reported; in 15 cases, physical contact was reported (e.g., the removal of a bat from the home or workplace or the presence of a bat in the room where the person had been sleeping), but no bite was documented; and in 11 cases, no bat encounter was reported. In these cases, an unreported or undetected bat bite remains the most plausible hypothesis because the genetic sequences of the human rabies viruses closely matched those of specific species of bats