This is an important disease of pigs caused by a herpes virus. The virus can remain hidden in nerves of the pig in a carrier state for long periods of time and then be reactivated. Once introduced into a herd the virus usually remains there and it can continually affect reproductive performance at varying levels. The virus can survive for up to three weeks outside the pig. Acute outbreaks of disease occur when virulent strains of the virus first infect an unvaccinated susceptible herd. The virus crosses the uterus and placenta and infects the foetuses.
The pig is the main host. Dogs and cattle may become infected, show nervous signs and die.
Symptoms
Sows
- Coughing.
- Fever
- Nervous signs
- Reproductive failure.
- Abortions.
- Mummified piglets.
- Stillbirths.
- Birth weak litters.
Piglets
- Nervous signs.
- Incoordination.
- Sneezing.
- Coughing.
- High mortality.
- Low / poor viable piglets.
Weaners & Growers
- Fever.
- Sneezing.
- Coughing.
- Pneumonia.
- Nervous signs including incoordination, fits and meningitis.
- Some strains of the virus can cause severe respiratory disease and others severe rhinitis.
- Usually low mortality.
All Other Species
- Nervous signs.
- Death.
Causes / Contributing factors
- Movement of carrier pigs.
- Virus airborne – at least 3km (2 miles).
- Infection from feral (wild) pigs.
- The role of mechanical spread by birds is questionable.
- Contaminated carcasses may spread infection.
- Mechanically on people.
- Contaminated vehicles.
- Through infected semen via AI or a carrier boar.
- From infected slurry.
- Within herds it may be spread by nose to nose contact, or by aerosol droplets.
- Periods of stress may activate disease.
- Continual production systems perpetuate disease.
Additionally:
- The presence of other infections such as PRRS and leptospira may increase the severity of disease.
Diagnosis
When a susceptible breeding herd first breaks down with this disease the clinical signs described above strongly suggest aujeszky’s disease and are almost diagnostic. Laboratory tests are required to confirm the diagnosis.