Pseudorabies (Aujeszky’s disease or mad itch) is an acute and highly fatal viral disease caused by a herpes virus (Su-HV1).
Pigs (swine) are the natural reservoirs of the virus but other mammals including cows, sheep, goats, dogs, rats, cats etc., are susceptible to infection. Pseudorabies occurs most often in cats who live on or around farms due to their exposure to pigs.
The name pseudorabies is due to the similarities between the “furious” form of rabies. The virus affects the nervous system and is typically acquired by ingestion of infected prey such as rats or uncooked pork. Cat to cat transmission doesn’t seem to be a problem.
The incubation period of pseudorabies is 3-6 days. Infection occurs after ingestion of the virus, entering the nerve fibres. The virus is almost always fatal in cats with death occurring within two days.
There are several modes of transmission which can occur with pseudorabies:
- Direct contact with an infected animal.
- Eating prey such as rodents who have the disease.
- Eating undercooked or raw meat from infected swine.
Symptoms of pseudorabies can initially suggest the cat has been infected with the rabies virus, however, pseudorabies runs a much shorter course.
Intense itching of the head and neck, which leads to self-mutilation as well as hypersalivation (excessive drooling) are the two most common symptoms of pseudorabies. Other symptoms may include:
- Behavioural changes such as restlessness and crying, other cats may become lethargic
- Shortness of breath
- Ataxia (unsteady gait)
- Muscle stiffness
- Head pressing
- Vestibular signs such as circling and head tilting
- Diarrhea and vomiting (occasionally)
Diagnosis of pseudorabies is made by a complete physical examination as well as a medical history, which will include possible exposure to pigs or raw pork products.
Rabies and pseudorabies do have similar symptoms, however, there are also differences between the two viral infections. Rabid cats display aggression but cats with pseudorabies don’t. Pseudorabies causes intense itching which does not occur in cats with rabies.
If the cat does recover, and this is rare, diagnosis can be made by measuring antibodies to the virus.
It is possible to isolate the virus from tissues at necropsy.
There is no treatment other than supportive care. Infection almost always kills within 48 hours.
As there is no treatment, prevention is the key approach. No vaccine exists for the disease, therefore it is important to prevent cats roaming, particularly in high-risk areas.
Do not feed cats raw or undercooked pork.
Is pseudorabies transmissible to people?
There is a small chance that the infection can be passed from cat to humans, take care when handling an animal suspected of carrying the disease.