North Dakota State University’s Extension Service veterinarian urges people to protect themselves and their animals against rabies.

Rabies is a fatal viral infection that kills an estimated 35,000 to 50,000 people and millions of animals around the world each year, according to NDSU Extension veterinarian Charlie Stoltenow.

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 says.

Recently, a bat with rabies was reported in Minnesota. The woman who was bitten was not going to submit it for testing until her son told her to do so.

The Centers for Disease Control and Prevention says people can’t tell if a bat has rabies just by looking at it. Rabies only can be confirmed in a laboratory. However, any bat that is active by day or is found in a place where bats usually are not seen, such as in a home or on a lawn, might be rabid. A bat that is unable to fly and can be approached easily could be sick.

Here are some prevention tips:

• Avoid contact with bats, skunks or raccoons.
• Make sure dogs, cats, ferrets, horses and high-value or frequently handled livestock have current rabies vaccinations.
• Do not 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 three to five days in domestic dogs and cats and up to eight days in skunks before the animals show clinical signs that they have the disease, according to Stoltenow. Also, signs of the disease generally take 14 to 90 days to show up in the victim of a rabid animal bite, although research shows the disease’s incubation period can be as short as nine days and as long as 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 will not survive outside a mammalian host in the environment for an extended period, and is killed easily 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, Stoltenow says. A rabies postexposure prophylaxis series is available for people who have been exposed to the disease, but the cost can exceed $5,000 per person.

NDSU Agriculture Communication – June 14, 2011