Rabies can infect domestic animals, wild animals and humans. Rabies is caused by a virus and transmitted by close contact with saliva from infected animals (ie. bites, scratches, licks on broken skin and mucous membranes). Once symptoms of the disease develop, rabies is fatal.
Rabies can be prevented by vaccination. Rabies vaccine is also curative if given post-exposure before the manifestation of clinical symptoms.
Symptoms of rabies are usually seen 2-8 weeks after contact with a rabid animal. In some cases it can take more than a year before the disease becomes apparent, in these cases the link to the event or cause of infection often cannot be made.
The rabies virus affects central nervous tissue. In the acute stage, signs of hyperactivity (furious rabies) or pareisis (dumb rabies) predominate.
Various neurological symptoms are then seen:
anxiety
confusion
slight or partial paralysis
excitation
agitation
aggression
hypersalivation
difficulty swallowing
hydrophobia (fear of water)
Symptoms usually progress towards paralysis and coma in cases of both furious and dumb rabies. Death usually occurs from respiratory paralysis within days after the onset of symptoms.
Laboratory tests are required to confirm the diagnosis of rabies ante-mortally in humans. The most commonly used test in animals is the Direct Fluorescent Antibody (DFA) test. The test is done post mortally on the brain tissue of animals suspected of having rabies.
For full details on diagnostic tests for rabies see Manual of Diagnostic Tests and vaccines for terrestrial animals, OIE web site.
Diagnosing rabies in humans Several laboratory tests are required to confirm a diagnosis of rabies. Saliva, serum, spinal fluid and skin biopsies are all examined and tested for rabies antigen or antibodies.
