Animals > Animal Diseases > Pseudorabies  

Pseudorabies

What is pseudorabies?

Pseudorabies, also known as Aujeszky’s disease, is a viral disease causing inflammation of the brain and spinal cord and respiratory infection in domestic and wild animals. The pig is the only natural host for pseudorabies virus; therefore, the disease is of greatest economic consequence to the pork industry. Sporadic fatal cases have been known to occur in cattle, sheep, goats, dogs, cats, mink, foxes, raccoons, and rats. Over the years, pseudorabies disease has increased in incidence and severity in many intensive pig-farming regions in the world, possibly due to changes in swine management practices towards highly intensive production systems.

Do we have this disease in Canada?

No. Pseudorabies is not present in Canada. Pseudorabies occurs worldwide in many countries. The United States has been actively working towards eradication of the disease since 1989 and in 2003 the eradication program is nearing its final stages.

Is there a human health risk associated with this disease?

No, there is no public health risk associated with pseudorabies.

How is pseudorabies transmitted?

Pseudorabies is highly contagious in pigs. In newly-infected herds, the disease spreads rapidly throughout the entire herd. The virus is present in secretions from the nose and mouth of infected pigs. The disease is spread mainly by the respiratory route and nose-to-nose contact between pigs. The primary risk factor for the introduction of pseudorabies into Canada is through importation of live pigs. The disease can be introduced into a healthy herd of swine by an infected pig that is not showing signs of illness. Transmission can also occur by contaminated drinking water, clothing, footwear, or equipment, and on rare occasions by contaminated meat products. Baby pigs can become infected in utero and through milk from an infected sow.

What are the clinical signs of this disease?

Acute central nervous system disease in newborn piglets that causes high mortality rates is highly characteristic of pseudorabies. Swine show different symptoms depending on age. Clinical signs are most likely to be seen in newborn pigs and breeding sows. The first sign of infection in a herd may be reproductive failure followed by neonatal disease.

• Newborn: The disease progresses rapidly, usually resulting in death. Entire litters may die. In very young pigs, the only sign may be an inability to move or stand up. Slightly older piglets may have a fever, loss of appetite, vomiting, and nervous system signs such as incoordination, drowsiness, muscle twitching, convulsions, and paralysis.
• Weaner pigs: The mortality rate is lower (five to 10 per cent). The above clinical signs may be present but respiratory signs are more prominent including coughing, sneezing, and laboured breathing.
• Grower and Finisher pigs: Respiratory disease is the most common sign. Mortality rates are low (one to two per cent).
• Adults: Infection in adult pigs is often mild or inapparent. Sows may have reproductive problems such as early embryonic mortality, abortion, mummified fetuses, stillbirths or the birth of weak and trembling pigs.

Infections in species other than pigs are almost always fatal. Symptoms may include intense itching, scratching and self mutilation, an inability to rise, incoordination, paralysis, and rapid death.

How is this disease diagnosed?

Laboratory work is required to diagnose pseudorabies. Testing is done on tissue and blood samples to detect the virus and antibodies to the virus.

Are there any treatments?

There is no specific treatment for pseudorabies. Vaccination can prevent illness and would alleviate clinical signs in acute cases of pseudorabies. Vaccination is used extensively in some countries to control the disease. In the United States, vaccination is part of the pseudorabies eradication program.

What is being done to prevent this disease from entering Canada?

Pseudorabies is a reportable disease under the Health of Animals Act. This means that all suspected cases must be reported to the Canadian Food Inspection Agency (CFIA). All reported suspect cases are immediately investigated by inspectors from the Agency. The CFIA imposes strict regulations on the import of animals and animal products from countries where pseudorabies is known to occur. These regulations are enforced through CFIA port-of-entry inspections.

Canada’s emergency response strategy in the event of an outbreak of a foreign animal disease is to eradicate the disease and re-establish the country’s disease-free status as quickly as possible. In an effort to eradicate pseudorabies, the CFIA would employ its "stamping out" policy, which would include:

• the humane destruction of all infected and exposed animals;
• surveillance and tracing of potentially infected or exposed animals;
• strict quarantine and animal movement controls;
• strict decontamination of infected premises;
• zoning to define infected and disease-free areas.

How to get more information?

Contact your Canadian Food Inspection Agency Area Office:

You can find your local Canadian Food Inspection Agency District Office on the CFIA Web site or by consulting the blue pages of your local phone directory.

September 2003
P0318E-03