York County, South Carolina, Horse Tests Positive for Rabies

Two people have been referred to their health care providers for consultation after being exposed to rabies in the Rock Hill area of York County by a horse that tested positive for the disease, the South Carolina Department of Health and Environmental Control (DHEC) reported Jan. 13.

The horse initially appeared to be lame but later progressed to exhibiting aggressive behavior. The two individuals were exposed to rabies while caring for the horse on Jan. 7. The horse was euthanized on Jan. 8 and submitted for testing to DHEC's laboratory, which confirmed rabies on Jan. 11.

South Carolina law requires pet owners to vaccinate dogs, cats, and ferrets. The law does not require owners of agricultural animals to vaccinate for rabies; however, rabies vaccines for cows, horses and sheep have been approved by the USDA. The American Association of Equine Practitioners considers the equine rabies vaccine a core one, meaning all horses should be vaccinated against the disease.

The DHEC strongly recommends that owners vaccinate:

  • All horses;
  • Any livestock that have frequent contact with humans;
  • Any livestock that are particularly valuable; and
  • Animals used for raw milk or raw milk product production.

Horses must be vaccinated for rabies before being transported out-of-state.

"To reduce the risk of getting rabies, we recommend that people use caution when pets or livestock exhibit sudden changes in behavior," said Sandra Craig of DHEC's Bureau of Environmental Health Services. "This is especially true if owners notice unknown injuries on their animals, or stray/wild animals seen mingling with livestock or pets.

"Every year, several hundred South Carolinians must undergo preventive treatment for rabies after being potentially exposed to the rabies virus," she continued. "Once symptoms of rabies are present in an animal, it is impossible to tell by appearance if an animal has rabies or some other condition that causes similar signs of illness, such as distemper or lead poisoning.”

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 rabies' clinical signs 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.

The horse is the first animal from York County to test positive for rabies in 2016. There have now been two confirmed cases of rabies statewide in 2016. Nine York County animals tested positive for rabies in 2015; there were 130 confirmed rabies cases in animals in South Carolina in 2015.

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