This virus is spread by mosquitoes and is only important in countries where the insects are prevalent. Most domestic animals are affected. It causes an encephalitis in the human. The pig is an important source of infection.

Symptoms

• No clinical effects.

• Mummified piglets
• Stillborn piglets
• Nervous signs in piglets - Fits and convulsions.
• Oedema fluid in piglets.

• Infertility in boars.
• Swollen testicles.

Causes / Contributing factors

• The presence of mosquitoes.
• Susceptible pigs (na?ve).
• Viral reservoirs in other species.

Diagnosis