Comparative analysis of the tick-borne encephalitis virus (TBEV) infection of unfed adult ixodid ticks Ixodes pavlovsky Pomerantsev 1946 and Ixodes persulcatus Schulze in the area of sympatria of their natural habitats

Abstract

With the use of the ELISA method to detect an antigen, reverse transcription with quantitative real-time PCR with subtype-specific fluorescent probes, phylogenetic analysis of E and NS1 gene nucleotide sequences, bioassays with suckling mice, hemagglutination and neuroinvasiveness tests there was made a comparison of the tick-borne encephalitis virus (TBEV) infection of ixodid ticks Ixodes persulcatus P.Schulze and Ixodes pavlovskyi Pomerantsev 1946 in the area of sympatria of their natural habitats in the Novosibirsk region during growth period of their populations with the replacement ofprevailing species of monodominant type of the ixodid population structure. The ratio of 2 tick species didn’t depend on biotopes ofpine or birch forest but rather on the distance from the Novosibirsk Scientific Center: the lower anthropogenic pressure the smaller I.pavlovskyi proportion. The TBEV rate (including both pathogenic and apathogenic for laboratory mice virus), spectra of the TBEV3 main genetic types, neurovirulence and hemagglutination activity were similarfor both I.persulcatus and I.pavlovskyi. However, the proportion ofpathogenic for laboratory mice virus and the TBEV Far Eastern subtype, as well as viral loads of Siberian and European types for the TBEV from I.pavlovskyi were significantly higher than those from I.persulcatus.