scholarly journals Disappearance of TBEV Circulation among Rodents in a Natural Focus in Alsace, Eastern France

Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 930
Author(s):  
Laure Bournez ◽  
Gerald Umhang ◽  
Marie Moinet ◽  
Jean-Marc Boucher ◽  
Jean-Michel Demerson ◽  
...  
Keyword(s):  
Small Mammals ◽  
Meteorological Conditions ◽  
Myodes Glareolus ◽  
Mountain Forest ◽  
Apodemus Flavicollis ◽  
Natural Focus ◽  
Serum Samples ◽  
Tick Borne Encephalitis ◽  
Western Border ◽  
Tick Borne Encephalitis Virus

Tick-borne encephalitis virus (TBEV) depends mainly on a fragile mode of transmission, the co-feeding between infected nymphs and larvae on rodents, and thus persists under a limited set of biotic and abiotic conditions. If these conditions change, natural TBEV foci might be unstable over time. We conducted a longitudinal study over seven years in a mountain forest in Alsace, Eastern France, located at the western border of known TBEV distribution. The objectives were (i) to monitor the persistence of TBEV circulation between small mammals and ticks and (ii) to discuss the presence of TBEV circulation in relation to the synchronous activity of larvae and nymphs, to the densities of questing nymphs and small mammals, and to potential changes in meteorological conditions and deer densities. Small mammals were trapped five times per year from 2012 to 2018 to collect blood samples and record the presence of feeding ticks, and were then released. Questing nymphs were collected twice a year. Overall, 1344 different small mammals (Myodes glareolus and Apodemus flavicollis) were captured and 2031 serum samples were tested for the presence of antibodies against TBEV using an in-house ELISA. Seropositive rodents (2.1%) were only found from 2012 to 2015, suggesting that the virus disappeared afterwards. In parallel, we observed unusual variations in inter-annual nymph abundance and intra-annual larval activity that could be related to exceptional meteorological conditions. Changes in the densities of questing nymphs and deer associated with the natural stochastic variations in the frequency of contacts between rodents and infected ticks may have contributed to the endemic fadeout of TBEV on the study site. Further studies are needed to assess whether such events occur relatively frequently in the area, which could explain the low human incidence of TBE in Alsace and even in other areas of France.

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

Pathogens ◽  
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.

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

2018 ◽  
Author(s):  
Marat Makenov ◽  
Lyudmila Karan ◽  
Natalia Shashina ◽  
Marina Akhmetshina ◽  
Olga Zhurenkova ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Ixodes Ricinus ◽  
Small Mammals ◽  
Encephalitis Virus ◽  
Myodes Glareolus ◽  
Gps Tracking ◽  
Bank Voles ◽  
Tick Borne Encephalitis ◽  
Two Samples ◽  
Tick Borne Encephalitis Virus

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.

TBE in Sweden

2020 ◽  
Keyword(s):  
Genetic Characterization ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Second Phase ◽  
Serum Samples ◽  
Tick Borne Encephalitis ◽  
Specific Immunoglobulin ◽  
Tick Borne Encephalitis Virus ◽  
First Time

Tick-borne encephalitis virus (TBEV) was isolated for the first time in Sweden in 1958 (from ticks and from 1 tick-borne encephalitis [TBE] patient).1 In 2003, Haglund and colleagues reported the isolation and antigenic and genetic characterization of 14 TBEV strains from Swedish patients (samples collected 1991–1994).2 The first serum sample, from which TBEV was isolated, was obtained 2–10 days after onset of disease and found to be negative for anti-TBEV immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA), whereas TBEV-specific IgM (and TBEV-specific immunoglobulin G/cerebrospinal fluid [IgG/CSF] activity) was demonstrated in later serum samples taken during the second phase of the disease.

MONITORING STUDIES OF ARBOVIRUS INFECTIONS TRANSMITTED BY MOSQUITOES ON THE TERRITORY OF THE VOLGOGRAD REGION

2019 ◽  
pp. 60-66
Author(s):  
E.V. Molchanova ◽  
D.N. Luchinin ◽  
A.O. Negodenko ◽  
D.R. Prilepskaya ◽  
N.V. Boroday ◽  
...  
Keyword(s):  
Virus Antigen ◽  
Elisa Test ◽  
Serum Samples ◽  
Blood Sucking ◽  
Tick Borne Encephalitis ◽  
Volgograd Region ◽  
Two Samples ◽  
Probable Presence ◽  
California Serogroup ◽  
Tick Borne Encephalitis Virus

The paper presents data from the monitoring studies’ results of arbovirus infections transmitted by mosquitoes in the Volgograd region. West Nile virus antigen (WNV) in 9 samples, Tahyna virus in one sample, Batai virus in two samples were detected in the study of 110 samples of field material (blood-sucking mosquitoes) by ELISA test. Antibodies to WNV in 16.58 percent of the samples, to tick-borne encephalitis virus in 1.08 percent, to viruses of the California serogroup and Ukuniemi in 1.09 percent, to the virus Sindbis in 2.17 percent were detected as a result of the study of blood serum samples from donors in the Volgograd region. Thus, we obtained data on the probable presence of the Batai, Sindbis, Ukuniemi and Californian serogroup viruses along with the circulation of WNV on the territory of the Volgograd region.

scholarly journals Relation of genetic phylogeny and geographical distance of tick-borne encephalitis virus in central Europe

2011 ◽  
Vol 92 (8) ◽  
pp. 1906-1916 ◽  
Author(s):  
M. Weidmann ◽  
D. Růžek ◽  
K. Křivanec ◽  
G. Zöller ◽  
S. Essbauer ◽  
...  
Keyword(s):  
Czech Republic ◽  
Central Europe ◽  
Encephalitis Virus ◽  
Natural Focus ◽  
The Czech Republic ◽  
Tick Borne Encephalitis ◽  
Disease Pattern ◽  
The Central Nervous System ◽  
Tick Borne Encephalitis Virus ◽  
First Time

Tick-borne encephalitis virus (TBEV) is the most important arboviral agent causing disease of the central nervous system in central Europe. In this study, 61 TBEV E gene sequences derived from 48 isolates from the Czech Republic, and four isolates and nine TBEV strains detected in ticks from Germany, covering more than half a century from 1954 to 2009, were sequenced and subjected to phylogenetic and Bayesian phylodynamic analysis to determine the phylogeography of TBEV in central Europe. The general Eurasian continental east-to-west pattern of the spread of TBEV was confirmed at the regional level but is interlaced with spreading that arises because of local geography and anthropogenic influence. This spread is reflected by the disease pattern in the Czech Republic that has been observed since 1991. The overall evolutionary rate was estimated to be approximately 8×10−4 substitutions per nucleotide per year. The analysis of the TBEV E genes of 11 strains isolated at one natural focus in Žďár Kaplice proved for the first time that TBEV is indeed subject to local evolution.

Tick-Borne Encephalitis Virus Diversity in Ixodid Ticks and Small Mammals in South-Western Siberia, Russia

2016 ◽  
Vol 16 (8) ◽  
pp. 541-549 ◽  
Author(s):  
Valentina N. Bakhvalova ◽  
Galina S. Chicherina ◽  
Olga F. Potapova ◽  
Victor V. Panov ◽  
Victor V. Glupov ◽  
...  
Keyword(s):  
Small Mammals ◽  
Western Siberia ◽  
Encephalitis Virus ◽  
Ixodid Ticks ◽  
Virus Diversity ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus

scholarly journals Tick-Borne Encephalitis Virus Habitats in North East Germany: Reemergence of TBEV in Ticks after 15 Years of Inactivity

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Silvius Frimmel ◽  
Anja Krienke ◽  
Diana Riebold ◽  
Micha Loebermann ◽  
Martina Littmann ◽  
...  
Keyword(s):  
Human Case ◽  
Encephalitis Virus ◽  
Federal State ◽  
Natural Focus ◽  
North East ◽  
Tick Borne Encephalitis ◽  
Close Relationship ◽  
Natural Foci ◽  
Tick Borne Encephalitis Virus ◽  
Migrating Birds

The incidence of tick-borne encephalitis has risen in Europe since 1990 and the tick-borne encephalitis virus (TBEV) has been documented to be spreading into regions where it was not previously endemic. In Mecklenburg-West Pomerania, a federal state in Northern Germany, TBEV was not detectable in over 16,000 collected ticks between 1992 and 2004. Until 2004, the last human case of TBE in the region was reported in 1985. Following the occurrence of three autochthonous human cases of TBE after 2004, however, we collected ticks from the areas in which the infections were contracted. To increase the chance of detecting TBEV-RNA, some of the ticks were fed on mice. Using nested RT-PCR, we were able to confirm the presence of TBEV in ticks for the first time after 15 years. A phylogenetic analysis revealed a close relationship between the sequences we obtained and a TBEV sequence from Mecklenburg-East Pomerania published in 1992 and pointed to the reemergence of a natural focus of TBEV after years of low activity. Our results imply that natural foci of TBEV may either persist at low levels of activity for years or reemerge through the agency of migrating birds.

High prevalence of West Nile virus in equines from the two provinces of Pakistan

2014 ◽  
Vol 143 (9) ◽  
pp. 1931-1935 ◽  
Author(s):  
A. ZOHAIB ◽  
M. SAQIB ◽  
C. BECK ◽  
M. H. HUSSAIN ◽  
S. LOWENSKI ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Japanese Encephalitis Virus ◽  
Large Scale ◽  
Encephalitis Virus ◽  
Serum Samples ◽  
West Nile ◽  
Elisa Kit ◽  
Tick Borne Encephalitis ◽  
High Prevalence ◽  
Tick Borne Encephalitis Virus

SUMMARYThis study describes the first large-scale serosurvey on West Nile virus (WNV) conducted in the equine population in Pakistan. Sera were collected from 449 equids from two provinces of Pakistan during 2012–2013. Equine serum samples were screened using a commercial ELISA kit detecting antibodies against WNV and related flaviviruses. ELISA-positive samples were further investigated using virus-specific microneutralization tests (MNTs) to identify infections with Japanese encephalitis virus (JEV), WNV and tick-borne encephalitis virus (TBEV). Anti-WNV antibodies were detected in 292 samples by ELISA (seroprevalence 65·0%) and WNV infections were confirmed in 249 animals by MNT. However, there was no animal found infected by JEV or TBEV. The detection of WNV-seropositive equines in Pakistan strongly suggests a widespread circulation of WNV in Pakistan.

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