The Stable Matching Problem in TBEV Enzootic Circulation: How Important Is the Perfect Tick-Virus Match?

Abstract

Tick-borne encephalitis virus (TBEV), like other arthropod-transmitted viruses, depends on specific vectors to complete its enzootic cycle. It has been long known that Ixodes ricinus ticks constitute the main vector for TBEV in Europe. In contrast to the wide distribution of the TBEV vector, the occurrence of TBEV transmission is focal and often restricted to a small parcel of land, whereas surrounding areas with seemingly similar habitat parameters are free of TBEV. Thus, the question arises which factors shape this focal distribution of TBEV in the natural habitat. To shed light on factors driving TBEV-focus formation, we used tick populations from two TBEV-foci in Lower Saxony and two TBEV-foci from Bavaria with their respective virus isolates as a showcase to analyze the impact of specific virus isolate-tick population relationships. Using artificial blood feeding and field-collected nymphal ticks as experimental means, our investigation showed that the probability of getting infected with the synonymous TBEV isolate as compared to the nonsynonymous TBEV isolate was elevated but significantly higher only in one of the four TBEV foci. More obviously, median viral RNA copy numbers were significantly higher in the synonymous virus–tick population pairings. These findings may present a hint for a coevolutionary adaptation of virus and tick populations.

A one health approach to investigating an outbreak of alimentary tick-borne encephalitis in a non-endemic area in France (Ain, Eastern France): a longitudinal serological study in livestock, detection in ticks, and the first TBE virus isolation and molecular characterization

“…We evaluated a minimal detection of infectious viral particle at 10 4 TCID50/mL of milk and 10 5 TCID50/ mL after dissolution of 2.5g of cheese. In ticks, the mean viral copy number lies between 2 × 10 2 to 4.8 x10 3 RNA copies per sample (Liebig, Boelke et al 2020, Liebig, Boelke et al 2021. Our data confirmed the high virus load detected in tank milk.…”

A One-Health Approach to Investigating an Outbreak of Alimentary Tick-Borne Encephalitis in a Non-endemic Area in France (Ain, Eastern France): A Longitudinal Serological Study in Livestock, Detection in Ticks, and the First Tick-Borne Encephalitis Virus Isolation and Molecular Characterisation

“…We evaluated a minimal detection of infectious viral particles at 10 4 TCID50/ml of milk and 10 5 TCID50/ml after dissolution of 2.5 g of cheese. In ticks, the mean viral copy number lies between 2 × 10 2 and 4.8 × 10 3 RNA copies per sample ( Liebig et al, 2020 , 2021 ). Our data confirmed the high virus load detected in tank milk.…”

Hybrids of Ixodes ricinus and Ixodes persulcatus ticks effectively acquire and transmit tick-borne encephalitis virus

“…line (Labuda et al, 1993;Slovaḱ et al, 2014;Khasnatinov et al, 2016), via intracerebral injection into suckling mice brains (Mishaeva and Erofeeva, 1979;Danielova, 1990), and by qPCR (Liebig et al, 2021;Mignéet al, 2022). The titer of infectious virus does not always reflect the true amount of TBEV, because it is determined by the effect of the virus on mammalian cells or organisms.…”