Rabies: Take the ounce of prevention

  • Published
  • By Heather Graves, DVM
  • 9th Force Support Squadron
September 28th is World Rabies Day. It may sound a little strange--a day devoted to raising public awareness of rabies and the threat it poses to humans--because unless you have lived in Asia, Africa, or a developing country, it's likely that rabies is something that you have never had personal experience with. On the one hand, this is a good thing, because rabies is a terrible, fatal disease. But on the other hand, living in a country where people rarely die of rabies tends to make us complacent. We start thinking that rabies doesn't happen in the U.S. Maybe we even think that it can't happen. We are a powerful nation with a well-developed medical system. Our dogs and cats are required by law to be vaccinated against rabies, a program so successful that canine rabies has been eradicated in the U.S. Rabies isn't us.

Unfortunately, the above assumptions are quite literally dead wrong.

Although canine rabies has been eradicated--meaning that the dog population of the United States no longer harbors rabies endemically--rabies is alive and well in our wildlife. Bats, raccoons, coyote, fox, opossums, and skunks all can carry rabies, and our pets (especially our cats) do come into contact with these animals. Furthermore, we may come into contact with them. And remember that rabies is capable of infecting any mammalian species, herbivores as well as carnivores. This extends the sphere of exposure risk tremendously.

Think of the following scenarios:

· The Good Samaritan who gets out of their car to shoo an opossum off of the road
· The hunter who brings down a deer
· The wildlife rehabilitator who takes in a fox cub
· The person who feeds and pets a stray cat that is wandering the neighborhood
· The jogger who encounters a raccoon
· The homeowner who discovers a bat in their house
· The fireman who rescues a stray cat trapped in a wall
· The animal control agent who responds to a complaint of a skunk in a garage
· The neighbor who returns a loose dog to its home
· The man who keeps just a couple of goats for milk or meat
· The horse owner
· The dairyman
· The shepherd

Every one of these people can be exposed to rabies.

Exposure to rabies occurs through wound or mucous membrane contact with the saliva or nervous system tissue of a rabid animal. The most common scenario is being bitten or scratched by a rabid animal. The key thing to remember is that you may not be able to tell that the animal is rabid. Not every rabid animal froths at the mouth or attacks without provocation. This means that when a person is bitten or scratched by a mammal, unless that animal has documented proof of rabies vaccination, the victim must be considered a possible rabies exposure and precautions must be taken. The degree of precaution depends on the species of animal, the prevalence of rabies in the area, and to a lesser degree, the circumstances of the injury. In certain situations, the victim is recommended to receive rabies post-exposure prophylaxis (PEP).

So how big a risk does rabies pose, really? Well, there are about 7,000 cases of rabies in animals reported each year, right here in the United States. And that is only the ones that are reported. Most of these cases are in wildlife, which isn't very cooperative about participating in studies. We have no way of knowing how many more cases go unobserved and unreported. But the bottom line is that even in the U.S., rabies is definitely out there. Studies estimate that within the U.S. every year, 30,000 to 40,000 people undergo rabies PEP due to possible exposure to rabies.

Each year, across the globe, 55,000 people die of rabies. Now we are talking about human cases, not animals, and 55,000 rabies deaths per year is a horrifying statistic. Many of these people die because they didn't realize the animal that bit or scratched them was rabid. Others did not seek medical care because they couldn't afford it. A very high percentage of these deaths are among children, who are the number one demographic for dog bites. Imagine being the parent of three children, all of whom are bitten by a dog that proves to be rabid. Can you afford to treat all three children . . . or do you have to choose which child to save? In parts of the world where rabies is endemic in feral dogs and cats, thousands of families are faced with this decision. Treatment is expensive, and each year people die because they and their families cannot afford to treat, or sought medical help too late.

When bitten by a rabid animal, the window of opportunity to protect the victim is limited, and it is also unpredictable. After a bite, the virus must migrate to the brain by way of the nerves, a process which can take weeks or months. During the migration period the victim will show no signs of rabies. This is the time window during which rabies PEP can be given, and the disease destroyed. However, once the virus reaches the brain, encephalitis and death follow. There is no treatment for a person or animal that is starting to show the signs of rabies. The closer to the head a bite occurs, the shorter the migration period, and the narrower the time window for treatment. Post-exposure prophylaxis is not the same thing as treating an active disease. PEP must be given before rabies reaches the brain, or it will fail.

So what can we do to protect ourselves?
1. Vaccinate all high-risk domesticated animals.
2. Vaccinate all humans at significant risk of exposure.
3. Know the enemy. Here are some things that everyone should know about rabies.

How does rabies exposure occur?

· Any mammal can carry rabies
· Be especially wary of wildlife, bats, and stray dogs and cats. These animals are at highest risk of carrying rabies
· Remember that horses, cows, goats, and sheep can also carry rabies
· Do not keep wild mammals as pets
· Do not encourage the approach of wild mammals, e.g. do not leave out food or trash for them

What are the signs of rabies in an animal?

· Staggering, stumbling, confusion, inability to get up
· Unusual friendliness, e.g. a wild animal that doesn't seem to be afraid or approaches you
· Aggression, sometimes extreme: this is the classic "rage" form of rabies
· Very withdrawn behavior/poorly responsive: Animals, especially cats, sometimes exhibit "dumb rabies," which manifests as a cat that doesn't respond when approached. A "dumb" rabid animal will lash out without warning at close range and inflict severe bite and scratch damage. They can be even more dangerous than the classic aggressive "mad" rabies animal, because their passive behavior encourages people to approach
· Drooling
· Biting at inanimate objects or at self
· Chewing/champing motions of the jaw ("foaming at the mouth" comes from this sign)
NEVER, under any circumstances, approach a mammal that is showing any of the above signs. If you can safely confine the animal without approaching it, do so. Call Animal Control immediately and keep adults, children, and pets away.

What should a person who was bitten or scratched do?

· Rabies exposure is an urgency, but not an emergency. In other words, stay calm. While there are steps that should be taken to protect yourself and others from rabies, you do have time in which to act. First aid care for the wound comes first, particularly if the wound is severe.
· Immediately wash the wound with large amounts of soap and warm water. Rabies virus is killed by soap. Although washing will not necessarily reach all of the virus, it will reduce the viral load.
· Contact your physician. If your doctor's office is closed, go to an emergency or urgent-care clinic.
· Contact local or state Public Health officials. If the animal is judged a rabies risk, then the situation must be monitored. Public Health is responsible for alerting other people to the risk of rabies exposure in their area.
· Contact Animal Control. Let them attempt to capture the animal. It will be either quarantined and observed (for pets) or tested directly for rabies (wildlife and some strays).
· Consider rabies prophylaxis. Your doctor can advise you regarding this procedure. For injuries to military personnel and their dependents, the base medical clinic and veterinarian will work together to determine whether the risk of rabies exposure is high enough to recommend PEP.
· If the bite occurs on base, a Bite Report must be filled out. Your doctor is responsible for filling it out, but you will need to supply some of the information. All bites or possible rabies exposures occurring on a base must be reported the same day.

What happens to an animal that bites/scratches a human?

· Pet animals must be immediately examined by a veterinarian.
· If the animal is a dog, cat, or ferret current on its rabies vaccine, it is put into quarantine for ten days (local law may require up to 14 days) and observed. If during that time it shows no signs of rabies, then it is released from quarantine. No rabies PEP is required for the victim of the bite. If, however, the animal dies or begins behavior consistent with rabies during quarantine, then the animal will be tested for rabies and the victim will be given rabies PEP.
· If the animal is an owned dog, cat, or ferret that is lapsed on its rabies vaccination, it is quarantined and observed for 45 days or longer depending on local rabies laws. Rabies PEP may be required for the victim of the bite.
· If the animal is not vaccinated and is behaving in a manner suggestive of rabies, it will be euthanized and tested for rabies regardless of whether it is a wild animal or a domestic species. If it is not vaccinated and its behavior is normal, euthanasia and testing may still be required depending on local rabies laws. If it is a wild animal, it will be euthanized and tested for rabies regardless of its behavior. Rabies PEP will be required for the victim of the bite.

What happens if my pet is bitten by another animal that is not vaccinated against rabies?

· If your pet is current on its rabies vaccine, it will receive a rabies vaccine booster. It will be closely monitored (possibly quarantined, depending on the situation) for 45 days, then released if there are no signs of rabies.
· If your pet has lapsed on its rabies vaccine, much depends on whether the biting animal can be captured and tested for rabies. If rabies is confirmed in the biting animal, the only options are to either euthanize the pet, or to quarantine and observe it for six months. If the biting animal cannot be captured, quarantine of the pet and observation for six months are required.

How do I prevent rabies in my pet?

· Vaccination is the primary means of protecting pets.
· All dogs, cats, and ferrets in the U.S. must be vaccinated against rabies. It's the law!
· Vaccination is also available for horses, cattle, rabbits, goats, and sheep.
· For certain pet species (ferrets, wolf hybrids) a special form of rabies vaccine is required. Although ferrets are not legal in California, most veterinarians will still vaccinate them in order to protect humans.
· Vaccinate your puppy or kitten for rabies at four months of age.
· Booster the rabies vaccine twelve months after the first vaccine.
· Depending on where you live, further boostering must be done every one, two, or three years.

How do I prevent rabies exposure for myself and my family?

· Vaccinate your dogs, cats, and ferrets against rabies and keep them current
· Spay or neuter your dogs and cats to reduce their urge to roam and get exposed to other animals.
· Never approach an animal that is behaving oddly.
· Avoid contact with wild animals and do not encourage their approach to your home.
· Teach your children to never, ever approach a wild animal, or a dog or a cat unless you and the pet's owner are both present and say it is OK. Even then, use your judgment.
· Never handle a bat in any manner. If you awaken to find a bat in your home, assume that it is rabid and that you have been bitten, even if you don't find a wound. Have the bat captured and tested by Animal Control, and ask for rabies prophylaxis.
· Let Animal Control deal with wildlife species that are in or near your home.
· License your dogs and cats. Licensing helps the county keep track of which animals are current on their rabies vaccine. If your pet strays and is picked up, a license will greatly help Animal Control get your pet back to you. Micro chipping is another important aid towards bringing strayed pets home.
· Report stray dogs to Animal Control. Remember that a straying animal is exposed to wildlife and may pick up rabies. Because of their wandering tendencies, it can be harder to tell if a cat is a stray or not; however, if there is a cat in your neighborhood that appears unkempt and thin, and no one will claim it, assume it is a stray and contact Animal Control. A stray dog or cat has a much greater chance of returning home, or finding a new home, when it is fed and housed in a shelter. If it is left on its own, it stands a good chance of being exposed to rabies, injured, or even killed.