Tick-borne encephalitis is caused by a virus of the flavivirus group, most commonly transmitted by the common tick (Ixodes ricinus). The virus can be transmitted by all developmental stages of the tick, i.e. larvae, nymphs and adults. Tick-borne encephalitis can also be contracted by the food route after ingestion of unpasteurised cow's, sheep's or goat's milk from infected animals.
In animals, infection is often asymptomatic. The most common clinical signs are fever, lethargy and, in more severe cases, nervous signs (increased sensitivity, muscle twitching and even paralysis of the limbs).
