Pseudorabies (Aujeszky’s Disease) in Dogs and Cats

1 Cause and Transmission

The pseudorabies virus is a herpesvirus with strong resistance in the environment, but ordinary chlorine and formaldehyde preparations kill it quickly and reliably; 0.1% peracetic acid and 1 to 2% quaternary ammonium compounds also work as disinfectants. Dogs are naturally infected mainly by eating the offal of infected pigs or rats (digestive route) and can also be infected through skin wounds. In addition, a dog’s urine and blood oozing from scraped or bitten skin can contaminate feed and water and spread the virus to healthy dogs.

2 Clinical Signs

The incubation period is 3 to 6 days, rarely up to 10. Early signs are indifference to the surroundings, then restlessness, refusal to eat, and increased thirst. The dog sits curled up. Temperature rises only intermittently, and vomiting is common. The wound site itches; the dog stares at and scratches or licks and bites the itchy spot, and within hours may develop extensive raw areas with surrounding swelling and even deep tissue loss. Sometimes this sign is absent and the dog just moans as if in pain somewhere.

Some cases resemble rabies, with the dog biting and shredding objects, but it never attacks people or livestock and may only fight other dogs when itching. Early pharyngeal paralysis appears, with drooling and inability to swallow. The pupils are often unequal in size. In most dogs the flexor muscles of the head and neck and the lip muscles show intermittent twitching. Breathing becomes difficult, and death usually occurs within 24 to 36 hours.

3 Differential Diagnosis

Any breed, sex, or age can be affected, and cases occur in all seasons. The dog shows intense, sometimes year-round itching at the wound site and extreme restlessness, but rarely attacks people or animals. Late-stage paralysis is less typical than in rabies, and there is generally no masticatory-muscle paralysis.

4 Prevention and Control

The main measures are strict rodent control and never feeding infected pork, let alone raw pork. Clean up dog feces and urine promptly and disinfect with 2% caustic soda. For valuable breeding dogs, early treatment with anti-pseudorabies hyperimmune serum can be effective. To prevent secondary infection, sulfonamide drugs may be used.