Comparative Microbiome Analysis of Three Epidemiologically Important Tick Species in Latvia.

(1) Background: Amplicon-based 16S rRNA profiling is widely used to study whole communities of prokaryotes in many niches. Here, we comparatively examined the microbial composition of three tick species, , and , which were field-collected in Latvia. (2) Methods: Tick DNA samples were used for microbiome analysis targeting bacterial 16S rDNA using next-generation sequencing (NGS).

Effectiveness of tick-borne encephalitis vaccination in Latvia, 2018-2020: an observational study.

Objectives: Tick-borne encephalitis (TBE) is an infection by the tick-borne encephalitis virus (TBEV) that results in symptoms of central nervous system inflammation. TBE is endemic in Latvia and other European countries. TBE vaccines are commonly used in Latvia, but vaccine effectiveness estimates are limited.

Effectiveness of Tick-borne Encephalitis Vaccines in Children, Latvia, 2018-2020.

Background: Tick-borne encephalitis (TBE) is an infection by the tick-borne encephalitis virus (TBEV) with symptoms of central nervous system inflammation. TBE is endemic in Latvia and other parts of Europe. TBE vaccination is recommended for children in Latvia.

Occurrence of spp. and spp. Infection in Humans in Latvia: Evidence of Underdiagnosed and Underreported Cases.

: Protozoan parasites- and -are important causes of diarrhea with an underestimated short-term burden on childhood growth and wellbeing in children under five years of age. The main transmission routes for both parasites are food and drinking water; transmission from person to person; and, due to their zoonotic nature, from domestic or wild animals to humans. The aims of the present study were to summarize the officially reported human cases of cryptosporidiosis and giardiasis in Latvia and to assess the occurrence of and in children within a prospective prevalence study.

Large-scale countrywide screening for tick-borne pathogens in field-collected ticks in Latvia during 2017-2019.

Background: Tick-borne diseases are of substantial concern worldwide in both humans and animals. Several hard tick species are of medical and veterinary interest in Europe, and changes in the range of tick species can affect the spread of zoonotic pathogens. The aim of the present study was to map the current prevalence and distribution pattern of ticks and related tick-borne pathogens in Latvia, a Baltic state in northern Europe.

Longitudinal study of prevalence and spatio-temporal distribution of Borrelia burgdorferi sensu lato in ticks from three defined habitats in Latvia, 1999-2010.

Members of the Borrelia burgdorferi sensu lato (s.l.) species complex are known to cause human Lyme borreliosis.

Tick-borne encephalitis: A 43-year summary of epidemiological and clinical data from Latvia (1973 to 2016).

Background: The incidence of tick-borne encephalitis (TBE) varies significantly over time. To better understand the annual incidence of all TBE cases in Latvia we investigated the disease burden in the country from 1973-2016 using several available sources and case definitions.

Methods: We identified cases of TBE from an electronic database (maintained by the Centre for Disease Prevention and Control of Latvia [CDPC]) by the use of ICD-10 diagnosis codes for TBE (A84; A84.

Prevalence and phylogenetic analysis of Babesia spp. in Ixodes ricinus and Ixodes persulcatus ticks in Latvia.

Babesia spp. are tick-borne protozoan parasites that have been reported in many European countries and are considered to be emerging pathogens. Several Babesia spp.

Multilocus sequence typing using mitochondrial genes (mtMLST) reveals geographic population structure of Ixodes ricinus ticks.

The hard tick Ixodes ricinus is the principal vector of Lyme borreliosis (LB) group spirochaetes in Europe, but it also transmits a large number of other microbial pathogens that are of importance to animal and human health. Here, we characterise geographically distinct populations of this important ectoparasite based on multilocus sequence typing (MLST) of multiple mitochondrial (mt) genes (mtMLST). Internal fragments of approximately 500 bp were amplified and sequenced for 6 protein-encoding and ribosomal genes (atp6, coi, coii, coiii, cytB, and 12s).

Detection and characterization of tick-borne encephalitis virus in Baltic countries and eastern Poland.

Ticks were collected from the vegetation in the Baltic countries Estonia, Latvia, Lithuania and eastern Poland and analyzed for the presence of tick-borne encephalitis virus (TBEV) by amplification of the partial E and NS3 genes. In Estonia we found statistically significant differences in the TBEV prevalence between I. persulcatus and I.

Driving forces for changes in geographical distribution of Ixodes ricinus ticks in Europe.

Many factors are involved in determining the latitudinal and altitudinal spread of the important tick vector Ixodes ricinus (Acari: Ixodidae) in Europe, as well as in changes in the distribution within its prior endemic zones. This paper builds on published literature and unpublished expert opinion from the VBORNET network with the aim of reviewing the evidence for these changes in Europe and discusses the many climatic, ecological, landscape and anthropogenic drivers. These can be divided into those directly related to climatic change, contributing to an expansion in the tick's geographic range at extremes of altitude in central Europe, and at extremes of latitude in Scandinavia; those related to changes in the distribution of tick hosts, particularly roe deer and other cervids; other ecological changes such as habitat connectivity and changes in land management; and finally, anthropogenically induced changes.

Association between Anaplasma phagocytophilum seroprevalence in dogs and distribution of Ixodes ricinus and Ixodes persulcatus ticks in Latvia.

Anaplasma phagocytophilum has been detected in ticks in Latvia; however, this is the first study to investigate this pathogen in dogs in Latvia. The aims of this study were: (i) to determine A. phagocytophilum seroprevalence in dogs, (ii) to correlate A.

Host migration impacts on the phylogeography of Lyme Borreliosis spirochaete species in Europe.

The geographic patterns of transmission opportunities of vector-borne zoonoses are determined by a complex interplay between the migration patterns of the host and the vector. Here we examine the impact of host migration on the spread of a tick-borne zoonotic disease, using Lyme Borreliosis (LB) spirochaetal species in Europe. We demonstrate that the migration of the LB species is dependent on and limited by the migration of their respective hosts.

Landscape predictors of tick-borne encephalitis in Latvia: land cover, land use, and land ownership.

Although the presence of tick-borne encephalitis (TBE) virus circulating in tick populations depends on large-scale patterns of climate, and the local density of infected ticks depends on the abundance of mammalian hosts, the risk of human infection depends on the access and use by human populations of tick-infested habitats, particularly forests, at the landscape level. We investigated the incidence of reported TBE cases in rural parishes (i.e.

A new Borrelia species defined by multilocus sequence analysis of housekeeping genes.

Analysis of Lyme borreliosis (LB) spirochetes, using a novel multilocus sequence analysis scheme, revealed that OspA serotype 4 strains (a rodent-associated ecotype) of Borrelia garinii were sufficiently genetically distinct from bird-associated B. garinii strains to deserve species status. We suggest that OspA serotype 4 strains be raised to species status and named Borrelia bavariensis sp.

Variable spikes in tick-borne encephalitis incidence in 2006 independent of variable tick abundance but related to weather.

Background: The incidence of tick-borne encephalitis showed a dramatic spike in several countries in Europe in 2006, a year that was unusually cold in winter but unusually warm and dry in summer and autumn. In this study we examine the possible causes of the sudden increase in disease: more abundant infected ticks and/or increased exposure due to human behaviour, both in response to the weather.

Methods: For eight countries across Europe, field data on tick abundance for 2005-2007, collected monthly from a total of 41 sites, were analysed in relation to total annual and seasonal TBE incidence and temperature and rainfall conditions.

MLST of housekeeping genes captures geographic population structure and suggests a European origin of Borrelia burgdorferi.

Lyme borreliosis, caused by the tick-borne bacterium Borrelia burgdorferi, has become the most common vector-borne disease in North America over the last three decades. To understand the dynamics of the epizootic spread and to predict the evolutionary trajectories of B. burgdorferi, accurate information on the population structure and the evolutionary relationships of the pathogen is crucial.

Behavioural responses to perceived risk of tick-borne encephalitis: vaccination and avoidance in the Baltics and Slovenia.

Tick-borne encephalitis (TBE) incidence increased markedly in the Baltics and Slovenia in the early 1990s, but then declined again in some places. Our analyses of temporal and spatial data on TBE incidence and vaccination revealed that over 1970-2005 up-take of vaccination varied in both time and space according to incidence, i.e.

Socio-economic factors in the differential upsurge of tick-borne encephalitis in Central and Eastern Europe.

Tick-borne encephalitis (TBE), the most serious widespread vector-borne disease of humans in Europe, increased from 2- to 30-fold in many Central and Eastern European countries from 1992 to 1993, coinciding with independence from Soviet rule. Unemployment and low income have been shown in Latvia to be statistically associated with high-risk behaviour involving harvest of wild foods from tick-infested forests, and also with not being vaccinated against TBE. Archival data for 1970--2005 record major changes in the agricultural and industrial sectors, and consequent changes in the abiotic and biotic environment and socio-economic conditions, which could have increased the abundance of infected ticks and the contact of humans with those ticks.

Climate change cannot explain the upsurge of tick-borne encephalitis in the Baltics.

Background: Pathogens transmitted by ticks cause human disease on a greater scale than any other vector-borne infections in Europe, and have increased dramatically over the past 2-3 decades. Reliable records of tick-borne encephalitis (TBE) since 1970 show an especially sharp upsurge in cases in Eastern Europe coincident with the end of Soviet rule, including the three Baltic countries, Estonia, Latvia and Lithuania, where national incidence increased from 1992 to 1993 by 64, 175 and 1,065%, respectively. At the county level within each country, however, the timing and degree of increase showed marked heterogeneity.

Tick-borne encephalitis in the Baltic States: identifying risk factors in space and time.

This paper presents preliminary results in our investigations of the biological (abiotic and biotic) and non-biological causes of the spatial heterogeneity and temporal change of tick-borne encephalitis (TBE), both within and between Estonia, Latvia, and Lithuania. Spatial analysis revealed that the land cover and precise seasonal patterns of climatic indices (temperature and normalized difference vegetation index) can explain 55% of the observed spatial variation in TBE incidence over the period 1993-98 across all the Baltic States. Temporal analysis of climatic variables indicates a very specific change in spring temperature conditions from 1993 onwards that could enhance the transmission of TBE virus.

Vectors of tick-borne diseases and epidemiological situation in Latvia in 1993-2002.

During the period of 1993-2002 an increase and the remarkable changes in the incidence of tick-borne encephalitis (TBE) and Lyme borreliosis (LB) as well as annual activities of vector species were noticed. The highest increase of TBE morbidity in Latvia has been observed in 1994 and 1995, and less expressed also in 1998 which was followed by a significant decrease during subsequent years. Whereas the highest peak of LB morbidity has been noticed in 1998 with only a minor decrease during subsequent years.