Surveillance of viral tick-borne zoonosis using novel strategies

Tick-borne encephalitis virus (TBEV) is the most important viral tick-borne zoonosis in Europe and infection often leads to severe CNS disease. TBEV and antibodies against TBEV are excreted in milk of goats, sheep and cattle and the virus can be ingested orally by consumption of non-pasteurized diary products, so-called alimentary TBE. Since prevalence of TBEV in the tick population is low there is a need for new and robust surveillance techniques identifying risk areas of TBEV at early stages. There is also very limited data on how climate changes affect the levels of TBEV inside the tick, e.g. if warmer temperatures increase the amount of virus in the ticks and thereby increase the risk of transmission between the tick and host at blood-feeding? We and others have reported that TBEV in ticks are not one single virus but consist of a cloud (quasi-species) of different virus types. The proportions of specific virus species within the cloud have been proposed to shifts when the virus environment changes from the tick to mammal, but it is yet not known how this may contribute to the virulence of TBEV.

We will here:

1. Develop robust and reliable techniques to identify TBE “hot-spot” regions by studying TBE in milk.
2. Characterize the importance of the 3’ variable region for TBEV virulence.
3. In depth analysis of how the quasi-species pool of TBEV is changed in questing ticks adjusting to environmental temperature changes and at higher temperatures during feeding on vertebrates.

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