Feb 18, 2017
Rabies is a severe, and often fatal, viral polioencephalitis that
specifically affects the gray matter of the dog's brain and its
central nervous system (CNS). The primary way the rabies virus is
transmitted to dogs in the United States is through a bite from a
disease carrier: foxes, raccoons, skunks, and bats. Infectious
virus particles are retained in a rabid animal's salivary glands to
better disseminate the virus through their saliva. 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
CNS via fluid within the nerves. The virus can take up to a month
to develop, but once the symptoms have begun, the virus progresses
rapidly. This inflammatory infection also has zoonotic
characteristics and can therefore be transmitted to humans. If you
would like to learn more about how this disease affects cats,
please visit this page in the petMD health library.
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, the 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, the paralytic stage, or a combination of the two,
while others succumb to the infection without displaying any major
symptoms. Furious rabies 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 treated soon after the
symptoms have begun, the
prognosis is poor.
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. The following are some of the symptoms of
rabies to watch for in your dog:
- Pica
- Fever
- Seizures
- Paralysis
- Hydrophobia
- 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
- Paralysis in the mandible and larynx
- Excessive salivation (hypersalivation), or frothy saliva
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, and very rarely through breathing in the escaping
gasses from decomposing animal carcasses. Contracting the virus in
this way is rare but it can occur, often in caves with large
populations of bats, where the virus is widespread. This may be a
concern for hunting dogs.
Diagnosing Rabies in Dogs
If you suspect your dog has rabies, call your veterinarian
immediately. If it is safe to do so, cage, or otherwise subdue your
dog, and take it 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. Your veterinarian will
keep your dog quarantined in a locked cage for 10 days. This is the
only acceptable method for confirming suspected rabies infection.
Rabies can be confused with other conditions that cause
aggressive behavior, so a laboratory blood analysis must be
conducted to confirm the presence of the virus. However, blood
testing for the virus is not veterinary procedure. Diagnosis
in the U.S. is done using a post-mortem direct fluorescence
antibody test
performed by a state-approved laboratory for rabies diagnosis. Your
veterinarian will collect fluid samples if your dog dies while in
quarantine, or
if it begins showing progressive signs of rabies; in which case,
your veterinarian will opt to put your dog to sleep (or euthanize
it).