Rabies is a serious viral disease seen in mammals that adversely affects the central nervous system, leading to death. Rabies is a zoonotic disease that is typically transmitted through bites from infected animals. The majority of reported cases involve wild animals like bats, raccoons, and skunks, but domesticated animals like dogs and cats are also at risk. Humans are equally susceptible to the rabies virus if bitten by an infected animal.
Once the symptoms have appeared, Rabies is nearly always fatal. Death usually occurs less than a week after the onset of signs.
The rabies virus is transmitted through the saliva of an infected mammal, or host. Contact with the eyes, nose or mouth can technically pass on the virus, but these instances are rare. A bite from the host is the most likely and common way for an animal or person to contract rabies. The infected saliva travels through the nerves and spinal cord towards the brain. The virus then incubates in the body for 3 to 8 weeks (depending on species), with no symptoms of the disease present. Once the brain is infected by rabies, the virus multiplies and spreads to the salivary glands and the symptoms of rabies appear.
Symptoms of Rabies
Rabies symptoms tend to vary, so affected dogs may not show all the signs. Initial signs include behavior and personality changes, fearfulness, anxiety, shyness, withdrawal from people and other animals, and licking the site of the original bite wound.
Signs progress to restlessness, agitation, and overreaction to sights and sounds. These lead to full-blown aggression, then disorientation followed by seizures. Dogs may also experience paralysis in the head and neck area. This causes inability to swallow, resulting in excess salivation, or "foaming at the mouth," and respiratory distress.
Sadly, death soon follows.
The only way to definitively diagnose rabies in dogs is through a direct fluorescent antibody test (dFA) using samples of brain tissue that can only be obtained after death. In humans, multiple extensive tests can be run with samples of saliva, blood, hair and skin, but these are not absolute, nor are they available for animals. Diagnosis in living animals is presumptive and based upon clinical signs and patient history. In pets that have been exposed to rabies, a quarantine period may be necessary to watch for signs of the disease, particularly in unvaccinated pets. Those with no vaccine history are usually euthanized.
Unfortunately, there is no cure or effective treatment for rabies. Animals with obvious and advanced signs of rabies must be euthanized. This is to avoid unnecessary suffering in the animal and to prevent further transmission of the disease to humans and other animals.
Humans exposed to rabies need to undergo a regimen called postexposure prophylaxis (PEP), a series of injections that include immune globulin and rabies vaccine.
However, PEP is not effective in humans after symptoms are noted. As with animals, rabies is almost always fatal once the signs appear. Supportive care is the only option at this point.
Prevention is key when it comes to rabies. Fortunately, it is also quite simple. First and foremost, dogs and other pets should receive routine rabies vaccines. The traditional rabies vaccine was given to dogs once per year but desires to decrease vaccine frequency led to the development of a three-year rabies vaccine. Talk to your vet about your options and find out what the law in your area mandates.
Rabies vaccines are also available for humans, though the protocol is more complicated. Therefore, the vaccine is typically only given to people who work with pets or wildlife, or those who travel to areas with high exposure risk. However, people who have received the vaccine will still need PEP after exposure to rabies.
Next to vaccination, minimizing exposure is the best way to prevent rabies. Do not allow your dog to roam out of your sight, especially in wooded areas where wild animal encounters are more common. Keep your dog on a leash, and avoid interactions with unknown animals. If your dog does get an animal bite, see your vet right away.
Preventing rabies in humans is equally important. Learn about dog bite prevention and teach your children how to be cautious. Bites to humans should be addressed immediately by a physician.
If a bite occurs, try your best to obtain as much information as possible about the offending animal, whether the bite victim is a pet or a human. If the biter was someone's pet, get their contact information and find out about the vaccine history and possible past exposure to rabies. If it was a wild animal, you may not be able to find out much unless that wild animal is dead. Either way, local authorities should be notified of the situation.
Despite how deadly and dangerous the rabies virus is, it is easily preventable. Remember: vaccinate your pets and minimize their exposure and yours. Arm yourself with the knowledge to keep your whole family safe, pets and humans alike.
Centers for Disease Control and Prevention