Aujeszky's disease (Pseudorabies (PRV))

The Aujeszky's disease is caused by a virus that can remain latent and causes respiratory, reproductive and nervous problems.

Description

It is a very important swine disease caused by a herpesvirus. The virus can remain latent in the nervous tissue of the pig for long periods of time, and be reactivated. Once the virus has been introduced in a farm, it normally persists in it and can continuously affect performance at different levels. The virus can survive up to 3 weeks outside the pig. Acute outbreaks of the disease can be produced when a virulent strain affects for the first time a susceptible farm, in which no vaccination against this disease has been practiced. The virus crosses the uterus and placenta and infects piglets. The pig is the main host. It can affect other species that normally do not transmit the disease, including cows, horses, dogs and cats, which can show nervous symptoms and die. There is no information regarding human infection.

Symptoms

Sows

  • Cough.
  • Pneumonia.
  • Nervous symptoms.
  • Reproductive failure.
  • Abortion.
  • Mummified piglets.
  • Piglets born death.
  • Weak litters at birth.

Lactating piglets

  • Nervous symptoms.
  • Incoordination.
  • Sneezing.
  • Cough.
  • Pneumonia.
  • Increased mortality.
  • Non-viable piglets.

Weaners and growers

  • Fever.
  • Sneezing.
  • Cough.
  • Pneumonia.
  • Some strains may cause severe respiratory disease and others can cause severe rhinitis.
  • Nervous signs including incoordination, seizures and meningitis.
  • Usually mortality is low. 

Other species

  • Nervous signs.
  • Death.


Causes / contributing factors

  • The field virus can be transmitted between farms through subclinically infectded pigs.
  • Airborne transmission can happen at a distance of severe kilometers.
  • Wild boars can transmit the disease.
  • The role of birds as mechanical carriers is in question
  • Contaminated water channels can spread the disease.
  • Humans are mechanical vectors.
  • Contaminated vehicles.
  • Contaminated semen.
  • Contaminated slurry.
  • Inside the farm it can be transmitted through direct contact or aerosols.
  • Stress periods can activate the disease.
  • Continuous production systems perpetuate the disease.

Additionally, the presence of other diseases like PRRS, classical swine fever, PCV2 etc. can increase the severity of the disease. 



Diagnosis

Serology analysis confirm the diagnosis.

Control/prevention

  • There is no available treatment, but antibiotic use in order to control secondary bacterial infections must be considered.
  • Vaccination must be done when an acute outbreak appears, or as a control or preventive measure.
  • Gilts and boars must be bought from farms free of Aujeszky’s disease and must be vaccinated at their arrival or in the quarantine area.
  • In order to maintain the disease outside the farm, isolate all new animals and obtain blood samples before they enter the farm.
  • If your farm is in danger of getting the disease, this means if there are infected farms in a radio of 3 km, vaccinate all the animals.
  • Eradication policies can vary from slaughter and repopulation to vaccination and serology. Due to the fact that the disease is slowly transmitted, it can be eradicated through vaccination, good management practices, and elimination of animals that carry the disease.

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