Differential susceptibility of geographically distinct Ixodes ricinus populations to tick-borne encephalitis virus and louping ill virus

Abstract

Tick-borne encephalitis virus (TBEV) is an emerging pathogen in the Netherlands. Multiple divergent viral strains are circulating and the focal distribution of TBEV remains poorly understood. This may, however, be explained by differences in the susceptibility of tick populations for specific viruses and viral strains, and by viral strains having higher infection success in their local tick population. We investigated this hypothesis by exposing Dutch Ixodes ricinus ticks to two different TBEV strains: TBEV-NL from the Netherlands and TBEV-Neudoerfl from Austria. In addition, we exposed ticks to louping Ill virus (LIV), which is endemic to large parts of the United Kingdom and Ireland, but has not been reported in the Netherlands. Ticks were collected from two locations in the Netherlands: one location without evidence of TBEV circulation and one location endemic for the TBEV-NL strain. Ticks were infected in a biosafety level 3 laboratory using an artificial membrane feeding system. Ticks collected from the region without evidence of TBEV circulation had lower infection rates for TBEV-NL as compared to TBEV-Neudoerfl. Vice versa , ticks collected from the TBEV-NL endemic region had higher infection rates for TBEV-NL compared to TBEV-Neudoerfl. In addition, LIV infection rates were much lower in Dutch ticks compared to TBEV, which may explain why LIV is not present in the Netherlands. Our findings show that ticks from two distinct geographical populations differ in their susceptibility to TBEV strains, which could be the result of differences in the genetic background of the tick populations.

Strain-Dependent Assessment of Powassan Virus Transmission to Ixodes scapularis Ticks

“…Experimental studies of POWV in ticks have been performed in Dermacentor variab [23,24], Haemaphysalis longicornis [25], Amblyomma americanum [24], and I. scapularis [24,2 Notably, these studies have relied on the use of highly passaged historical virus stra Importantly, it has been shown that I. ricinus ticks have different levels of susceptibility genetically distinct TBEV strains, demonstrating a potential impact of virus genotype tick infection [27]. With the emergence of POWV in North America, the use of low-p sage, contemporary, genetically, and geographically diverse isolates is essential for an curate representation of tick transmission.…”

Ixodes ricinus as potential vector for Usutu virus

“…The large differences in transstadial transmission rates in these studies may be explained by the differences in physiological conditions of these ticks. Infection success of viruses in ticks after an infectious bloodmeal is influenced by tick origin and collection date [ 30 , 57 ]. Moreover, microbiota of arthropods differ between laboratory-reared and field-collected specimens [ 58 ].…”

“…An artificial membrane blood-feeding system was adapted from Oliver et al [ 28 ] and Krull et al [ 29 ] with several modifications as described in [ 30 ]. The blood-feeding unit consisted of a polycarbonate tube (50 x 30 x 2 mm, Flexinplex kunstoffen, the Netherlands) glued to a silicon membrane and closed with a cultivation plug for Drosophila .…”