Ixodid ticks and tick-borne encephalitis virus prevalence in the South Asian part of Russia (Republic of Tuva).
Animal Distribution
Animals
Arachnid Vectors
/ virology
Dermacentor
/ growth & development
Ecosystem
Encephalitis Viruses, Tick-Borne
/ isolation & purification
Encephalitis, Tick-Borne
/ epidemiology
Ixodes
/ growth & development
Larva
/ growth & development
Nymph
/ growth & development
Prevalence
Russia
/ epidemiology
Altitude
Dermacentor nuttalli nymphs
Dermacentor ticks
Ixodes persulcatus
Overwintering
TBEV steppe foci
Tick-borne encephalitis virus
Journal
Ticks and tick-borne diseases
ISSN: 1877-9603
Titre abrégé: Ticks Tick Borne Dis
Pays: Netherlands
ID NLM: 101522599
Informations de publication
Date de publication:
08 2019
08 2019
Historique:
received:
12
11
2018
revised:
03
04
2019
accepted:
25
04
2019
pubmed:
20
5
2019
medline:
20
11
2019
entrez:
20
5
2019
Statut:
ppublish
Résumé
The most significant processes of arbovirus evolution can be expected to occur in the territories where ticks of different species cohabitate and at the boundaries of virus occurrence, where the probability of the appearance of new virus variants is high due to the possible shift in the main vectors and/or vertebrate hosts. One of the most interesting regions in this regard is the Republic of Tuva. Since most of its territory is covered by mountain ranges and intermountain basins, we were able to study the distribution of vectors and viruses in geographically isolated areas at different altitudes and in various landscapes. From 2008 to 2017, we conducted six expeditions to Tuva and collected 3,077 adult ticks and 24 nymphs. The distribution of tick species was confined to specific landscapes, as follows: Dermacentor nuttalli occurred in steppes, D. silvarum inhabited forest-steppe areas, and Ixodes persulcatus inhabited mixed forests. All three species of ticks were collected on plains and mountain slopes. The range of D. silvarum was shown to be lower than 1300 m above sea level (a.s.l.). Only D. nuttalli and I. persulcatus were collected at higher altitudes. According to our observations, single nymphs of D. nuttalli appear on animals one month before larvae appear. This finding confirms the hypothesis that the immature forms of D. nuttalli are able to overwinter under favourable conditions. We isolated 9 strains and 3 isolates of tick-borne encephalitis virus (TBEV) from I. persulcatus, one strain from D. nuttalli and one strain from D. silvarum. The TBEV strain from D. nuttalli was isolated from the territory inhabited only by Dermacentor ticks. All isolated strains belong to the Siberian subtype of TBEV. TBEV was detected in ticks from all the investigated altitudes. There were no statistically significant differences in the virus prevalence between the Dermacentor and Ixodes ticks. The results of our work provide additional support for the hypothesis of the existence of TBEV foci in areas with an absolute dominance of D. nuttalli.
Identifiants
pubmed: 31103456
pii: S1877-959X(18)30468-0
doi: 10.1016/j.ttbdis.2019.04.019
pii:
doi:
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
959-969Informations de copyright
Copyright © 2019 The Authors. Published by Elsevier GmbH.. All rights reserved.