Rabies

Rabies is a viral disease commonly associated with dogs, although in recent years canine rabies has been practically eliminated in North America and Europe due to extensive and often mandatory vaccination requirements. However it is still a significant problem in Africa, the Middle East, Latin America, and Asia. Dogs are considered to be the main reservoir for rabies in developing countries. Areas that are rabies-free, such as Britain, Ireland, Australia, and the American state of Hawaii have strict quarantine laws to keep their territories rabies-free. These require long periods of isolation and observation of imported animals, which makes them unattractive places to move with a pet unless the pet is quite young. Areas that are not rabies-free usually require that dogs be vaccinated against rabies.

photo: udel.edu

Historically, rabies has long been linked to dogs. The earliest mention of rabies is in the Codex of Eshnunna, which dictates that the owner of a dog showing symptoms of rabies should take preventative measure against bites. If a person was bitten by a rabid dog and later died, the owner was fined heavily. The sacred animal of the Babylonian goddess of health Gula or Ninisina was the dog; if a person insulted a dog, Gula caused that dog to bite the person and inflict them with rabies. In the 1800s the infectious nature of rabies was first demonstrated by taking the saliva from a rabid dog and injecting it into another animal.

Rabies in dogs is a fatal disease transmitted by the bite of an infected mammal, such as a cat, raccoon, bat, or another dog. Animals with rabies suffer deterioration of the brain and tend to behave bizarrely and often aggressively, increasing the chances that they will bite another animal or a person and transmit the disease. Three stages of rabies are recognized in dogs and other animals. The first stage is a one to three day period characterized by behavioral changes and is known as the prodromal stage. The second stage is the excitative stage, which lasts three to four days. It is this stage that is often known as furious rabies due to the tendency of the affected dog to be hyperreactive to external stimuli and bite at anything near. The third stage is the paralytic stage and is caused by damage to motor neurons. Incoordination is seen due to rear limb paralysis and drooling and difficulty swallowing is caused by paralysis of facial and throat muscles. Death is usually caused by respiratory arrest.

A person or dog bitten by an unknown dog should always be treated without waiting for symptoms, given the potentially fatal consequences of a rabid biter: there have been very few cases of someone surviving rabies when treatment was not begun until after symptoms appeared. Depending on local laws, dogs that are showing neurological signs at the time of the bite are euthanized in order to have their brain tested for rabies. Unvaccinated healthy dogs need to be confined for ten days from the time of the bite. If the dog is not showing signs of rabies at the end of ten days, then the bitten person could not have been exposed to rabies. Dogs and cats do not have the rabies virus in their saliva until a few days prior to showing symptoms. Ten day confinement does not apply to other species. A dog or cat bitten by a wild animal in an area known to have rabies should be confined for six months, because it can take that long for symptoms to start. This is an incentive to dog-owners to vaccinate their dogs even if they feel the risk of their dog contracting rabies is low, since vaccination will eliminate the need for their dog to be euthanized or impounded should it bite anyone or be suspected of biting anyone.