Survival dynamics of tick-borne encephalitis virus in Ixodes ricinus ticks.

Biotic factors contributing to the survival of tick-borne viruses in nature are poorly understood. Using tick-borne encephalitis virus (TBEV) and its principal European vector, Ixodes ricinus, we examined the relative roles of salivary gland infection, co-feeding transmission, and moulting in virus survival. Virus titres in the salivary glands increased after blood-feeding in a time- and dose-dependent manner.

Evaluation of chimeric yellow fever 17D/dengue viral replication in ticks.

Chimeric yellow fever 17D/DENV-1-4 viruses (CYD-1-4) have been developed as a tetravalent dengue vaccine candidate which is currently being evaluated in efficacy trials in Asia and America. While YF 17D and DENV are mosquito-borne flaviviruses, it has been shown that CYD-1-4 do not replicate after oral infection in mosquitoes and are not transmitted to new hosts. To further document the risk of environmental dissemination of these viruses, we evaluated the replication of CYD-1-4 in ticks, the vector of tick-borne encephalitis virus (TBEV), another member of the flavivirus family.

Non-hemagglutinating flaviviruses: molecular mechanisms for the emergence of new strains via adaptation to European ticks.

Tick-borne encephalitis virus (TBEV) causes human epidemics across Eurasia. Clinical manifestations range from inapparent infections and fevers to fatal encephalitis but the factors that determine disease severity are currently undefined. TBEV is characteristically a hemagglutinating (HA) virus; the ability to agglutinate erythrocytes tentatively reflects virion receptor/fusion activity.