By Dr. Abdul Ali Wallana
Rabies is a fatal viral polioencephalitis that specifically affects the gray matter of a dog’s brain and the central nervous system (CNS).
In the United States (except Hawaii), it is legally required that every owned dog be vaccinated against the rabies virus. Depending on your location and local law, this must be repeated every year to three years, depending on the rabies vaccine used.
Causes of Canine Rabies
The rabies virus is a single-stranded RNA virus of the genus Lyssavirus, in the family Rhabdoviridae. It is transmitted through the exchange of blood or saliva from an infected animal.
The primary way the rabies virus is transmitted to dogs in the United States is through a bite from wild animals like foxes, raccoons, skunks and bats that carry the disease. The virus is transmitted through biting and possibly scratching—it gets transferred in the saliva and is highly infectious.
Once the virus enters the dog’s body, it replicates in the cells of the muscles and then spreads to the closest nerve fibers, including all peripheral, sensory and motor nerves, traveling from there to the brain. The virus can take up to a month to develop but usually takes less than 10 days. Once rabies symptoms in dogs have begun, the virus progresses rapidly.
Rabies is infectious to humans. Rabies is also transmittable to cats.
Symptoms and Types of Rabies in Dogs
There are two forms of rabies: paralytic and furious. In the early symptom (prodomal) stage of rabies infection, a dog will show only mild signs of CNS abnormalities. This stage will last from one to three days. Most dogs will then progress to either the furious stage or the paralytic stage, or a combination of the two, while others succumb to the infection without displaying any major symptoms.
Furious rabies in dogs is characterized by extreme behavioral changes, including overt aggression and attack behavior. Paralytic rabies, also referred to as dumb rabies, is characterized by weakness and loss of coordination, followed by paralysis.
This is a fast-moving virus. If it is not addressed before the symptoms of rabies in dogs have begun, the prognosis is grave. Therefore, if your dog has been in a fight with another animal, or has been bitten or scratched by another animal, or if you have any reason to suspect that your pet has come into contact with a rabid animal (even if your pet has been vaccinated against the virus), you must take your dog to a veterinarian for preventive care immediately.
If you are unsure of the vaccine status of your pet or the other animal in the fight, bring your pet to your veterinarian or the emergency clinic immediately.
The following are some of the symptoms of rabies in dogs. However, if you have any reason to suspect that your pet has been exposed to rabies, call your veterinarian immediately. Do NOT wait until you notice symptoms, because by then it is too late to save your pet.
- Jaw is dropped
- Inability to swallow
- Change in tone of bark
- Muscular lack of coordination
- Unusual shyness or aggression
- Excessive excitability
- Constant irritability/changes in attitude and behavior
- Excessive salivation (hypersalivation), or frothy saliva
Diagnosing Rabies in Dogs
If you suspect your dog has been exposed to rabies, call your veterinarian immediately. If it is safe to do so, cage or otherwise subdue your dog, and take her to a veterinarian to be quarantined. If your pet is behaving viciously or is trying to attack, and you feel you are at risk of being bitten or scratched, you must contact animal control to catch your dog for you.
If your dog is up to date on vaccines, your veterinarian will give your pet an additional dose of the dog rabies vaccine and then quarantine him for 10 days. If your dog bit a human or is not up to date on his rabies vaccine, the next step will depend on state or local laws but usually includes mandatory quarantine. Rabies can be confused with other conditions that cause aggressive behavior, so a diagnosis is based on history of possible exposure.
Diagnosis in the US is done using a post-mortem direct fluorescence antibody test performed by a state-approved laboratory for rabies diagnosis. This means that the test can only be performed on dogs after they have died or been euthanized.
Treatment for Rabies in Dogs
If your dog has been vaccinated against rabies, your dog will receive a booster rabies vaccine from your veterinarian. If anyone came into contact with the dog’s saliva or was bitten by your dog, advise them to contact a physician immediately for treatment. Unfortunately, rabies is always fatal for unvaccinated animals, usually occurring within 7 to 10 days from when the initial symptoms began.
If a diagnosis of rabies is confirmed, your veterinarian is required to report the case to your local health department. An unvaccinated dog that is bitten or exposed to a known rabid animal must be quarantined for up to six months, or according to local and state regulations. A vaccinated animal that has bitten or scratched a human, conversely, will be quarantined in an approved facility or be euthanized, and post-mortem testing will be performed.
Living and Management
Once you have taken your dog to the veterinarian, disinfect any area the animal might have infected (especially with saliva) using a 1:32 dilution (4 ounces to a gallon) of household bleach solution to quickly inactivate the virus. Do not allow yourself to come into contact with your dog’s saliva.
Rabies is a fatal virus. The best way to prevent the virus is to vaccinate your dog based on the schedule recommended by your veterinarian and local health department.