Survival dynamics of tick-borne encephalitis virus in Ixodes ricinus ticks.
Slovák M., Kazimírová M., Siebenstichová M., Ustaníková K., Klempa B., Gritsun T., Gould EA., Nuttall PA.
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. This was observed in ticks infected by inoculation but not in ticks infected by the natural route of co-feeding. Amplification of infection prevalence occurred via co-feeding. However, when larvae or nymphs subsequently moulted, the infection prevalence dramatically declined although this was not observed when ticks were infected by inoculation. Trans-stadial survival is a hitherto overlooked parameter that may contribute to the low incidence of TBEV infection in field-collected I. ricinus ticks.