North Dakota State University (NDSU) Extension veterinarian Charlie Stoltenow is urging people to protect themselves and their animals against infection with rabies, a fatal viral infection that kills an estimated 35,000-50,000 people and millions of animals worldwide each year. The most common way to get rabies is from a bite of an animal with the disease. Infection through fresh wounds or mucous membranes is less likely but possible.

Stoltenow offers these prevention tips:

  • Make sure dogs, cats, ferrets, horses and high-value or frequently handled livestock have current rabies vaccinations.

  • Avoid contact with skunks, bats or raccoons.

  • Don’t perform oral exams on animals that appear to have difficulty chewing or swallowing, exhibit any type of oral or facial paralysis or show excessive salivation. Veterinarians should use extreme caution when doing oral exams on such animals.

  • Contact local animal-control authorities about animals you suspect have rabies.

Behavioral changes and unexplained paralysis are two indications of rabies. Other warning signs are anorexia, apprehension, nervousness, irritability, hyperactivity, isolation, lack of coordination, altered vocalization, changes in temperament and uncharacteristic aggressiveness.

Rabies exists in two forms: furious and dumb.

  • Animals with the furious type are irrational and will attack other animals, people or moving objects at the slightest provocation or noise. They assume an alert position and expression with dilated pupils and may chew or swallow foreign objects. Lack of muscular coordination, paralysis and death follow.

  • Symptoms of dumb rabies include paralysis of the throat and jaw muscles, profuse salivation and difficulty swallowing. Animals may drop their jaws. Death eventually follows.

The rabies virus may be in saliva for 3-5 days in domestic dogs and cats and up to eight days in skunks before the animals show clinical signs, Stoltenow says. Signs of the disease generally take 14-90 days to show up in the victim of a rabid animal bite, though research shows the disease's incubation period can be nine days up to seven years.

"The variability is due to a variety of factors, such as the location of the wound, severity of the wound, distance from the brain, and amount and strain of the virus introduced," he says.

Once transmitted by a bite, the virus stays at the bite site for a considerable amount of time. It replicates in muscle cells and travels along nerves to the spinal cord and brain, and then to the salivary glands.

The rabies virus won’t survive outside a mammalian host in the environment for an extended period of time, and is easily killed by soap and water, and common disinfectants.

Initial human symptoms include apprehension, excitability, headache, fever, malaise and sensory changes at the bite site. As the disease progresses, victims suffer from paralysis, difficulty swallowing, delirium and convulsions. Eventually they go into a coma and die, usually from respiratory failure.

People who suspect they've been exposed to rabies should contact their doctor immediately. A rabies post-exposure prophylaxis series is available for people exposed to the disease, but the cost can exceed $5,000/person.
-- NDSU Ag Communication