If there was ever a disease to strike fear into the hearts and minds of pet owners everywhere, rabies is it!
Rabies is a deadly viral disease that can infect any warmblooded mammal. It is one of the earliest diseases to ever be recorded, dating back to almost 2000 B.C. Rabies is found worldwide, except in a few countries like Great Britain and Japan, which have strict laws designed to keep themselves rabies -free. The incidence of rabies within the United States varies with each state, depending upon the normal fauna of that state and on existing rabies vaccination laws.
It is estimated that over 80 percent of all rabies cases occur in wildlife, with the remaining rabies cases spilling over into the domestic pet and livestock population. It is these latter groups that pose the greatest rabies threat to public health. Wildlife rabies most commonly shows up in skunks, raccoons, coyotes, foxes, and bats. Opossums are relatively resistant to rabies virus and rarely become infected. Rodents, such as rats, mice, and squirrels are not significant carriers of rabies either, since most don't survive encounters with rabies infected animals in the first place.
Skunk rabies is most prevalent in the Midwest, Southwest, and California; raccoon rabies in the MidAtlantic and Southeastern United States; fox rabies in the Eastern states; and bat rabies is a problem in all states. Most rabies cases in wildlife seem to occur during the spring and fall months of the year. The rabies virus is usually transmitted via the infected saliva of affected animals through bite wounds or contamination of open wounds or mucous membranes with the same saliva.
Rabies is uniformly fatal once contracted. Dogs are a major vector for transmission of rabies to humans. Studies have shown that rabies occurs at a higher incidence in younger dogs, the median age being about one year. In addition, due to roaming and territorial instincts, intact male dogs are at greater risk of exposure to rabies than are females. Cats are often exposed to rabies through their nighttime roaming activities. Cats have also been known to catch rabies infected bats that enter homes or attics, exposing themselves and in some instances, family members, to the rabies virus in the process.
The Three Stages of Rabies
Traditionally, when speaking of rabies, most people visualize a snarling, frothing dog snapping at anything in sight. While this is true in some instances of rabies, pet owners should understand that this represents only one of three stages of rabies that are part of the overall disease process. Depending upon each individual rabies case, viciousness might take on a prominent role, or might not occur at all.
The three stages of rabies include the prodromal stage, the furious stage, and the dumb or paralytic stage. The first stage of rabies, lasting from one to three days, is characterized by a change in the overall behavior of the animal. Normally friendly dogs might suddenly exhibit aggressive tendencies towards their owners or towards other pets in the household. Affected individuals might also hide a lot, preferring to be left alone, and becoming upset when disturbed. Loss of appetite with rabies might become apparent, and owners might notice an increased sexual arousal and/or frequency of urination involving their pet.
Once the prodromal stage of rabies is complete, the rabies victim then enters into the furious stage. This is the stage of rabies most persons equate with a traditional rabies presentation. Dogs and cats in this rabies stage often become quite restless, excitatory, and aggressive, losing fear of natural enemies. They might wander about aimlessly, snapping and biting at anything that moves. Rabies may cause the character of the pet's vocalizations to change. In dogs especially, pica, or an abnormal desire to eat anything within reach (i.e., rocks, wire, dirt, feces, etc.), might become apparent with this rabies stage.
As the disease caused by rabies enters the third stage, the swallowing reflex becomes paralyzed, making it impossible to eat, drink, or swallow saliva. This is what accounts for the excessive drooling seen in animals infected with rabies. The furious stage of rabies might last for up to a week before progressing into stage three, the paralytic stage of rabies. Owners should be aware of the fact that some animals, especially dogs, might skip the furious stage of rabies entirely, going directly from the prodromal stage into the paralytic stage of rabies. When this happens, rabies can be easily mistaken for other nervous system disorders. Because this quick transition can occur, the risk of human exposure to the rabies is greatly increased.
The paralytic stage of rabies presents itself as a general loss of coordination and paralysis. Animals infected with rabies may exhibit a droopy lower jaw with the mouth simply hanging open. Rabies induced paralysis and death usually overtakes the unfortunate animal in a matter of hours.
Rabies should be suspected anytime a dog or cat exhibits behavioral changes with unexplained, abnormal nervous system signs. Unfortunately, the only way to definitively diagnose is to have a laboratory analysis performed on the animal's brain tissue, which means of course, euthanasia of the pet.
There is no known treatment for rabies; as a result, stringent rabies control and vaccination measures are a must. All puppies and kittens should receive a rabies immunization between three and four months of age. In most states, a licensed veterinarian must administer this rabies vaccine. Depending on the rabies vaccine used and on the state in which you live, a booster rabies immunization is required every one to three years. Owing to the public health implications of rabies, pet owners who fail to keep their pets current on their rabies vaccinations are putting their own health at risk!
Other preventive control measures that can be taken to safeguard against rabies include discouraging free roaming, especially at night, and keeping all pets restrained on a leash when walking outside. Repairing or constructing fences and enclosures to help keep wild animals and potential carriers of rabies out of a pet's play area or living area will also help reduce chances of rabies exposure.
If a stray or wild animal bites a dog or cat already vaccinated for rabies, a booster rabies immunization should be administered within 36 hours. The pet should also be placed in rabies quarantine for a minimum of 90 days, unless the particular animal that did the biting can be found and its rabies status confirmed as negative. If the pet is bitten by a known carrier of rabies and has never been vaccinated for rabies before, only two options exist: 1) Quarantine the pet for at least six months in an approved rabies quarantine facility, or 2) euthanize the pet. Obviously, neither of these options are good ones.
Laws in most states spell out regulations concerning rabies vaccinations, bites involving humans, and the ownership of wildlife in order to curb the impact of rabies. Any rabies vaccinated pet that bites a human must be placed in rabies quarantine for a minimum of ten days to observe for signs of rabies. If suspicious signs appear, the animal is euthanized and samples are sent to the laboratory to confirm or dispel the rabies diagnosis. If the pet has not had a rabies vaccine in the past, or if a wild animal is involved, euthanasia and prompt laboratory examination of the brain tissue for rabies virus is warranted.
Finally, if a pet has been vaccinated for rabies, but is over-due on the rabies booster, rabies quarantine or euthanasia may be elected, depending on how over-due the pet is and the wishes of the person who was bitten. Euthanasia of rabies suspects should be carried out only by veterinarians or other public health and/or wildlife officials to ensure that the samples that reach the lab have been properly handled and stored. Any person bitten by an animal should contact his/her physician. Prophylactic rabies treatment may be started on the bitten individual until the rabies quarantine period is over or until the specific laboratory test results are in.
It is interesting to note that because the concentration of the rabies virus in an infected dog's saliva might be low or even absent in some cases, less than 50 percent of all bites from rabies infected dogs will result in the transmission of the disease. Yet because there is no way of knowing which bites fit into this category, prophylactic rabies treatment is a must, just to be on the safe side!
Ownership of wild animals, especially skunks and raccoons, should be avoided. First, there are no licensed rabies vaccines available for these "wild" pets. Secondly, because the rabies incubation period can last for months, owners might be exposing themselves to rabies right from the start without knowing it. Finally, in many states, it is against the law to own wildlife without a permit.
A Final Word To Parents About Rabies
Parents should always discourage children from interacting with stray animals or wildlife. Their natural curiosity could lead to a serious bite wound and much anxiety, especially if the offender is not found.