Pathogenesis and Transmission
Seropositivity for TBEV has been found in nature in many different wild and also domesticated animals, including dogs. However, the risk for a tick-infected dog to develop clinical manifest TBE is obviously rather small.
A TBEV infection evokes a life-long immunity. For the pathogenicity of the Siberian and Far-eastern TBEV subtypes in dogs no information is available.
Pathogenesis in humans
TBEV seems to be primarily pathogenic for humans. Human infection follows the bite of infected ticks, usually in people who visit or work in forests, fields, or pastures. The severity of disease, incidence of sequelae, and case-fatality rates are higher in the Far East and eastern regions of Russia than in western and central Europe. Out of the three virus subtypes the European subtype causes the mildest form of clinical disease in humans while the Far-eastern subtype exhibits the most severe form of clinical illness in humans.
TBEV replicates in ticks leading to a constant and high virus titre in the arthropod. In contrast to bacterial and protozoal transmission, the virus enters the mammal host during the early tick feeding. Therefore, repellent parasiticides may be the right choice to minimize attachment and subsequent feeding of the tick vector.Infection also can be acquired by consuming unpasteurized dairy products from infected cows, goats, or sheep.
- Bjöersdorff A: Borreliosis and tick-borne encephalitis. In: Arthropod-borne Diseases. 2002, Sci. Proc. BSAVA Congress, Birmingham, pp 185-6