First detection of tick-borne encephalitis virus in Ixodes ricinus ticks and their rodent hosts in Moscow, Russia

AbstractHere, we report the first confirmed autochthonous tick-borne encephalitis case diagnosed in Moscow in 2016 and describe the detection of Tick-borne encephalitis virus (TBEV) in ticks and small mammals in a Moscow park.The paper includes data from two patients who were bitten by TBEV-infected ticks within the Moscow city limits; one of these cases led to the development of the meningeal form of TBE. Both TBEV-infected ticks attacked patients in the same area. We collected ticks and trapped small mammals in this area in 2017. All samples were screened for the presence of pathogens causing tick-borne diseases by PCR. The TBEV-positive ticks and small mammals’ tissue samples were subjected to virus isolation. The sequencing of the complete polyprotein gene of the positive samples was performed.A total of 227 questing ticks were collected. TBEV was detected in five specimens of Ixodes ricinus. We trapped 44 small mammals, mainly bank voles (Myodes glareolus) and pygmy field mice (Apodemus uralensis). Two samples of brain tissue from bank voles yielded a positive signal in RT-PCR for TBEV. We obtained six virus isolates from the ticks and brain tissue of a bank vole. Complete genome sequencing showed that the obtained isolates belong to the European subtype and have low diversity with sequence identities as high as 99.9%. GPS tracking showed that the maximum distance between the exact locations where the TBEV-positive ticks were collected was 185 m. We assume that the forest park was free of TBEV and that the virus was recently introduced.

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Tick-Borne Encephalitis Virus: Seasonal and Annual Variation of Epidemiological Parameters Related to Nymph-to-Larva Transmission and Exposure of Small Mammals

Pathogens ◽

10.3390/pathogens9070518 ◽

2020 ◽

Vol 9 (7) ◽

pp. 518

Author(s):

Laure Bournez ◽

Gerald Umhang ◽

Marie Moinet ◽

Céline Richomme ◽

Jean-Michel Demerson ◽

...

Keyword(s):

Small Mammals ◽

Temporal Variations ◽

Encephalitis Virus ◽

Myodes Glareolus ◽

Mountain Forest ◽

Annual Variations ◽

Tick Borne Encephalitis ◽

Tick Borne Encephalitis Virus ◽

Over Time ◽

Epidemiological Parameters

A greater knowledge of the ecology of the natural foci of tick-borne encephalitis virus (TBEV) is essential to better assess the temporal variations of the risk of tick-borne encephalitis for humans. To describe the seasonal and inter-annual variations of the TBEV-cycle and the epidemiological parameters related to TBEV nymph-to-larva transmission, exposure of small mammals to TBEV, and tick aggregation on small mammals, a longitudinal survey in ticks and small mammals was conducted over a 3-year period in a mountain forest in Alsace, eastern France. TBEV prevalence in questing nymphs was lower in 2013 than in 2012 and 2014, probably because small mammals (Myodes glareolus and Apodemus flavicollis) were more abundant in 2012, which reduced tick aggregation and co-feeding transmission between ticks. The prevalence of TBEV in questing nymphs was higher in autumn than spring. Despite these variations in prevalence, the density of infected questing nymphs was constant over time, leading to a constant risk for humans. The seroprevalence of small mammals was also constant over time, although the proportion of rodents infested with ticks varied between years and seasons. Our results draw attention to the importance of considering the complex relationship between small mammal densities, tick aggregation on small mammals, density of infected questing nymphs, and prevalence of infected nymphs in order to forecast the risk of TBEV for humans.

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Long-term presence of tick-borne encephalitis virus in experimentally infected bank voles (Myodes glareolus)

Ticks and Tick-borne Diseases ◽

10.1016/j.ttbdis.2021.101693 ◽

2021 ◽

Vol 12 (4) ◽

pp. 101693

Author(s):

Anna Michelitsch ◽

Christine Fast ◽

Franziska Sick ◽

Birke Andrea Tews ◽

Karin Stiasny ◽

...

Keyword(s):

Encephalitis Virus ◽

Myodes Glareolus ◽

Bank Voles ◽

Tick Borne Encephalitis ◽

Tick Borne Encephalitis Virus

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In Vivo Characterization of Tick-Borne Encephalitis Virus in Bank Voles (Myodes glareolus)

Viruses ◽

10.3390/v11111069 ◽

2019 ◽

Vol 11 (11) ◽

pp. 1069 ◽

Cited By ~ 3

Author(s):

Michelitsch ◽

Tews ◽

Klaus ◽

Bestehorn-Willmann ◽

Dobler ◽

...

Keyword(s):

Bank Vole ◽

Whole Blood ◽

Clinical Signs ◽

Encephalitis Virus ◽

Myodes Glareolus ◽

Bank Voles ◽

Tick Borne Encephalitis ◽

Tbev Strain ◽

Tick Borne Encephalitis Virus

Tick-borne encephalitis is the most important tick-transmitted zoonotic virus infection in Eurasia, causing severe neurological symptoms in humans. The causative agent, the tick-borne encephalitis virus (TBEV), circulates between ticks and a variety of mammalian hosts. To study the interaction between TBEV and one of its suspected reservoir hosts, bank voles of the Western evolutionary lineage were inoculated subcutaneously with either one of eight TBEV strains or the related attenuated Langat virus, and were euthanized after 28 days. In addition, a subset of four strains was characterized in bank voles of the Carpathian linage. Six bank voles were inoculated per strain, and were housed together in groups of three with one uninfected in-contact animal each. Generally, most bank voles did not show any clinical signs over the course of infection. However, one infected bank vole died and three had to be euthanized prematurely, all of which had been inoculated with the identical TBEV strain (Battaune 17-H9, isolated in 2017 in Germany from a bank vole). All inoculated animals seroconverted, while none of the in-contact animals did. Viral RNA was detected via real-time RT-PCR in the whole blood samples of 31 out of 74 inoculated and surviving bank voles. The corresponding serum sample remained PCR-negative in nearly all cases (29/31). In addition, brain and/or spine samples tested positive in 11 cases, mostly correlating with a positive whole blood sample. Our findings suggest a good adaption of TBEV to bank voles, combining in most cases a low virulence phenotype with detectable virus replication and hinting at a reservoir host function of bank voles for TBEV.

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THE IDENTIFICATION OF «NEW» PATHOGENS FOR FOCAL INFECTIONS IN IXODES TICKS ON THE TERRITORY OF TULA REGION

Epidemiology and Infectious Diseases (Russian Journal) ◽

10.18821/1560-9529-2019-23-4-172-177 ◽

2018 ◽

Vol 23 (4) ◽

pp. 172-177

Author(s):

T. V. Kozlova ◽

T. I. Khomyakova ◽

V. G. Dedkov ◽

M. V. Safonova ◽

L. S. Karan ◽

...

Keyword(s):

Lyme Disease ◽

Ixodes Ricinus ◽

Mixed Infection ◽

Dermacentor Reticulatus ◽

Encephalitis Virus ◽

Tick Borne Encephalitis ◽

Ixodes Ticks ◽

Pcr Method ◽

Tick Borne Encephalitis Virus ◽

Human Monocytic Ehrlichiosis

The most of ixodes ticks in Tula region belongs to the group of pasture mites. It is generally accepted to estimate the tick’s contamination by the tick-borne encephalitis virus and raoueti inducing Lyme Borellia. The aim of the present work was to educe the aetiologic agents of the set of potentially-enable infections out of ticks Dermacentor reticulatus, Ixodes ricinus and Ixodes сrenulatus collected at the different terrains of Tula Region by PCR method. The results: a considerable number of pathogenic rickettsiae R. raoultii was educes from the ticks D. reticulatus, which including them as the component of mixed infection together with the human monocytic ehrlichiosis agent. R. raoultii was determined in more than a half of the cases in ticks I. ricinus including the mixed infection together with ticks’ borreliosis virus and Kemerovo fever agent. Conclusion. The reasons, induced the quantity changes of the ticks’ distribution at Tula Region terrains, apparently promote the rise in frequency of the ticks contamination with the agents of herd tick-transmissive infection. It demand an infectiologist’s attention rise and dictate the necessity of the above mentioned diseases monitoring as well as Fr. tularensis, the tick-borne encephalitis virus and Lyme disease.

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