Cause and spread
- Cause
- Rabies virus and related lyssaviruses.
- How it spreads
- Through the saliva of an infected animal, usually from a bite. The virus travels along nerves to the brain; incubation is usually 2 to 3 weeks to 3 months, but can be days to over 6 months.
- People
- Rabies is deadly to people. Anyone bitten or scratched by a suspect animal must wash the wound with soap and water and see a doctor immediately for post-exposure treatment.
Signs to watch for
- Fearfulness, restlessness and unusual aggression or unusual affection
- Excessive salivation and difficulty swallowing
- Changes in behaviour, or the sudden death of an apparently healthy animal
- Paralysis in the later stages
- In pigs, a violent excitation at the start
- Almost always fatal within days of signs
Many diseases look alike. Only a laboratory test can tell them apart, so please see a veterinarian for any sick animal.
How it is diagnosed
In animals rabies is usually confirmed after death by testing the brain. Tests during life on saliva or skin samples are less reliable, and a negative result does not rule rabies out. Handle samples only with proper protection and ask the laboratory first.
Prevention and control
- Vaccinate dogs and cats, and livestock in areas where rabies is common
- Do not let pets roam, and avoid contact with stray and wild animals
- Quarantine and observe animals that have bitten someone, as advised by the local authority
- Report suspected rabies to your veterinarian and the local health authority
Where this information comes from
- Rabies (factsheet) · Center for Food Security and Public Health, Iowa State University
General information for animal owners and veterinarians, last checked October 2026. It does not replace the advice of your veterinarian, who should decide which tests and treatment your animal needs.