Rabies Confirmed in Montana Horse
On Sept. 8, officials at the Montana Department of Livestock (MDOL) received confirmation of a Ravalli County horse that was diagnosed with rabies. As a result of the diagnosis, four people are seeking post-exposure rabies treatment and the state is monitoring 15 horses for potential exposure.
To reduce the risk of spread by animals that may have already been exposed, they have quarantined the county for 60 days. The 60-day county quarantine applies to dogs, cats and ferrets in Ravalli County that are not currently vaccinated for rabies. The quarantine is in effect from Wednesday, Sept. 8, to Sunday, Oct. 31. Animals past-due for a rabies booster, animals that are not 28 days past their first rabies vaccine, and animals that have never been vaccinated are subject to the quarantine.
The confirmation marks Montana’s 12th case of rabies, and the fifth in a non-bat species, in 2021.
Rabies—a zoonotic disease that can be spread from animals to humans—is caused by a lyssavirus that affects the neurologic system and salivary glands. Horses are exposed most commonly through the bite of another rabid animal.
In horses, clinical signs of rabies are variable and can take up to 12 weeks to appear after the initial infection. Although affected horses are sometimes asymptomatic, an infected horse can show behavioral changes such as drowsiness, depression, fear, or aggression. Once clinical signs appear, there are no treatment options.
Rabies can only be diagnosed postmortem by submitting the horse’s head to a local public health laboratory to identify the rabies virus using a test called fluorescence antibody. Thus, ruling out all other potential diseases first is very important in these cases to avoid potentially unnecessary euthanasia.
Because rabies threatens both horses and the humans who handle them, the American Association of Equine Practitioners (AAEP) recommends rabies as a core vaccine every U.S. horse should receive. The AAEP’s vaccination guidelines recommend that adult horses receive an initial single dose and a booster vaccination annually; foals born to vaccinated mares should receive a first vaccine dose no earlier than at six month of age and a second dose four to six weeks later followed by annual vaccination; and foals of unvaccinated mares should receive a first vaccine dose at three or four months of age and should be revaccinated annually.
Stay on top of the most recent Horse Health news with