Rabies is a virus that invades the central nervous system and produces an acute, progressive encephalitis (inflammation of the brain) that ends in death. It is usually transmitted via the saliva of a rabid animal:
- Through a bite
- Through contamination of scratch wounds
- Via mucosal membranes.
Rabies occurs only in mammals, so it is not present in birds, reptiles, amphibians or fish.
Rabies can be transmitted from infected animals to humans (zoonosis), which makes it a serious public health concern. Each year in Canada, approximately 3,000 people receive post-exposure treatment as a result of contact with rabid animals. In 60% of those cases, the contact is with rabid dogs or cats.
Rabies has gained a strong foothold in Canadian wildlife, growing in prevalence over the past two decades. Foxes, skunks, and raccoons are amongst the most common carriers of the disease. The presence of these animals in urban and suburban environments means chance encounters with pets is a very real possibility.
Rabies virus can be transmitted in the saliva up to seven days prior to the appearance of any clinical signs.1
Therefore, all bites to humans should be reported and handled as if they were suspicious — including evaluating, isolating and observing the animal for 10 days — regardless of clinical signs.
- Incubation averages two to four weeks.
- Clinical signs range from paralysis to abnormal behavior and are often confused with other equine neurologic disorders, such as sleeping sickness and West Nile virus.
- Early signs are rare, and many people may be exposed to a rabid horse before diagnosis.
- Clinical signs at the time of initial examination usually include weakness of hindquarters (ataxia and paresis), lameness and colic.
- After an excitation period, paralytic signs occur that can cause difficulty in swallowing, followed by lack of coordination of the extremities.
- Horses usually die within a week of the first clinical signs.³