Symptoms of Swine Fever in Pigs

What is Swine Fever?

Swine fever is caused by a virus and is one of the most economically devastating diseases for pig farmers. It spreads rapidly through direct contact between pigs, contaminated feed or water, or even through people, vehicles, and equipment that have been in contact with infected animals. The virus targets the immune system and blood vessels, leading to a range of severe symptoms and often death.

Key Symptoms to Observe

Farmers should be vigilant for a combination of these signs, as they can indicate the presence of swine fever:

• High Fever: Affected pigs will have a very high body temperature, often ranging from 105°F to 107°F (40.5°C to 41.6°C).
• Loss of Appetite (Anorexia): Sick pigs will refuse to eat or drink, leading to rapid weight loss.
• Lethargy and Weakness: Pigs become dull, listless, and prefer to lie down, often huddling together. They may be reluctant to move.
• Skin Discolouration: Red or purple blotches often appear on the ears, snout, abdomen, inner thighs, and tail. These spots do not blanch when pressed.
• Eye Discharge: Sticky discharge from the eyes (conjunctivitis) is common.
• Digestive Issues: Initially, pigs may show constipation, followed by severe, often bloody, diarrhoea. Vomiting can also occur.
• Respiratory Signs: Coughing and difficulty breathing may be observed in some cases, especially in later stages or with secondary infections.
• Neurological Signs: In some pigs, particularly in the later stages, symptoms like incoordination, wobbly gait, tremors, convulsions, and paralysis (especially of the hind legs) can develop.
• Hemorrhages: Small pinpoint bleeding spots (petechiae) can sometimes be seen on the skin or mucous membranes.

Acute vs. Chronic Forms

Swine fever can present in different forms, depending on the virulence of the virus and the pig's immune status:

Acute Form

This is the most common and severe form. Symptoms appear suddenly and are intense. Pigs develop high fever, severe depression, loss of appetite, and skin lesions. Death usually occurs within 5 to 15 days of symptom onset. Mortality rates can be very high, often reaching 90-100% in susceptible herds.

Chronic Form

This form is less common and occurs when pigs survive the acute phase or are infected with a less virulent strain. Symptoms are milder but prolonged. Pigs may show intermittent fever, poor growth, emaciation, chronic diarrhoea, and skin lesions that may become necrotic. These pigs often die from secondary bacterial infections over several weeks or months.

Differentiating from Other Diseases

It is important to note that some symptoms of swine fever, such as fever, loss of appetite, and skin discolouration, can be similar to those of other pig diseases, most notably African Swine Fever (ASF). Other conditions like Erysipelas or Salmonellosis can also cause overlapping signs. Therefore, a definitive diagnosis requires laboratory testing by a qualified veterinarian. Never assume it's a less serious disease.

What to Do if You Suspect Swine Fever

If you observe any of the symptoms mentioned above in your pigs, immediate action is crucial to prevent a wider outbreak:

• Isolate Sick Animals: Immediately separate any sick pigs from the healthy ones to prevent further spread.
• Contact Your Veterinarian: Inform your local veterinary officer or animal husbandry department without delay. They will be able to diagnose the disease and advise on control measures.
• Restrict Movement: Do not move or sell any pigs from your farm. Also, restrict the movement of people, vehicles, and equipment in and out of your farm.
• Biosecurity: Enhance biosecurity measures, including strict disinfection of premises and equipment.

Early detection and prompt reporting of swine fever symptoms are critical for controlling this devastating disease. By being vigilant and acting quickly, farmers can help protect their own herds and the wider pig farming community from significant economic losses.