Once bitten: Study may give hope to pets with out-of-date rabies vaccine that are exposed to virus

SCHAUMBURG, Ill., Jan. 6, 2015 /PRNewswire-USNewswire/ -- A tragic decision was forced on a loving dog owner when her pet was bitten by a rabid skunk. Because the dog was only days overdue for its rabies booster vaccine, the owner, according to published news stories, was forced to choose between a lengthy period of quarantine for her pet or euthanizing it. In this sad case, the pet owner made the painful decision to end her dog's life through euthanasia.

It is situations such as this that prompted a group of researchers to embark on a study to see whether they could make a difference and help avoid similar cases in the future. The results of their efforts appear in a scientific report in the Jan. 15, 2015, issue of the Journal of the American Veterinary Medical Association, and they help paint what might be a clearer picture about the options veterinarians and public health officials have when faced with similar situations.

"The general public gets to see cases like this once a year," said Dr. Mike Moore, project manager for the rabies lab at the Kansas State University College of Veterinary Medicine's Veterinary Diagnostic Laboratory and the report's lead author. "We get calls like this – if not weekly – every other week. I was a practicing veterinarian for 23 years, and it's really, really sad for me not to be able to help these people."

The study shows that pets whose rabies vaccination was considered out-of-date at the time of exposure to a rabid animal responded well after receiving an immediate rabies booster and did not develop any signs of the illness. The authors hope that the findings bring some clarity to guidelines that currently call for such animals to face lengthy periods of quarantine or be euthanized.

"Up to now, there hasn't been any scientific data presented for animals that are out-of-date on their vaccinations," Moore said. "Public health officials didn't have any measurable way to make their decision. Our results show that the two groups of animals – those that are out-of-date and those that are up-to-date – respond the same, and we feel they should be treated the same. If animals considered out-of-date have been primed with an initial vaccine, then when they're boostered after exposure, their titer goes up really high, really fast, and that's what we want in the case of exposure to rabies."

When confronted with cases of confirmed or suspected rabies exposure, veterinarians and public health officials typically refer to or rely on the Compendium of Animal Rabies Prevention and Control for guidance. According to the current version of the compendium, dogs and cats with current rabies vaccination status that have been exposed to an animal confirmed or suspected to be rabid should immediately receive a rabies booster vaccination and be observed for 45 days, most often under the pet owner's supervision with no contact restrictions.

The compendium guidelines are less clear when it comes to recommendations for dogs and cats overdue for a booster vaccination, suggesting that these animals be evaluated on a case-by-case basis that takes into account a number of criteria. Unfortunately, this recommendation for a case-by-case risk assessment, coupled with concerns for public safety, a fear of liability and the lack of published clinical data, commonly leads to conservative handling of these animals, which most often means either euthanasia or a six-month quarantine.

"Hopefully this closes the gap," said report co-author Rolan Davis, reference diagnostician at the Kansas State Veterinary Diagnostic Laboratory rabies lab. "The one paying the ultimate price in situations like this is the pet. It's our hope that people will report every instance of possible exposure to rabies and not be penalized if they are five days overdue."

The authors are careful to point out that all pets should be vaccinated at the appropriate age and should receive their regular rabies boosters. The study, while providing hope to pets considered out-of-date who have been exposed to rabies, also reinforces the critical importance of that initial rabies vaccine.

"Animals don't communicate if they have had a possible exposure," Davis said. "They can't tell us if they've had an encounter with a rabid animal. Routine vaccination covers for those exposures that the owners might not recognize. That's why pet owners can't vaccinate once and forget about it."

Moore and Davis are available for media interviews, and the AVMA has also produced a podcast that includes Moore talking about the study.

The AVMA, founded in 1863, is one of the oldest and largest veterinary medical organizations in the world, with more than 85,000 member veterinarians worldwide engaged in a wide variety of professional activities and dedicated to the art and science of veterinary medicine.

SOURCE American Veterinary Medical Association

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