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. Methods Nearly 4600 Ixodes ricinus , I. persulcatus and Dermacentor reticulatus tick samples were collected in all regions of Latvia during 2017–2019 and were screened by molecular methods to reveal the prevalence and distribution pattern of a wide spectrum of tick-borne pathogens. Results New localities of D. reticulatus occurrence were found in western and central Latvia, including the Riga region, indicating that the northern border of D. reticulatus in Europe has moved farther to the north. Among the analyzed ticks, 33.42% carried at least one tick-borne pathogen, and 5.55% of tick samples were positive for two or three pathogens. A higher overall prevalence of tick-borne pathogens was observed in I. ricinus (34.92%) and I. persulcatus (31.65%) than in D. reticulatus (24.2%). The molecular analysis revealed the presence of tick-borne encephalitis virus, Babesia spp., Borrelia spp., Anaplasma phagocytophilum and Rickettsia spp. Overall, 15 and 7 tick-borne pathogen species were detected in Ixodes spp. and D. reticulatus ticks, respectively. This is the first report of Borrelia miyamotoi in Latvian field-collected ticks. Conclusions This large-scale countrywide study provides a snapshot of the current distribution patterns of Ixodes and Dermacentor ticks in Latvia and gives us a reliable overview of tick-borne pathogens in Latvian field-collected ticks.

Although the number of new tuberculosis (TB) cases registered per year has decreased by 3-fold between 2001 and 2017 in Latvia, the TB incidence and rates of multidrug resistant TB in this Baltic country remain substantially higher than in most other European countries. Molecular typing methods of Mycobacterium tuberculosis (MTB) play an important role both in clinical studies of the disease and the epidemiological investigations, allowing to describe and characterize the pathogen's population structure and spread of particular genotypes. Aim of this study was to examine the prevalence of MTB lineages in Riga and Riga region of Latvia within a five-year period (2008 -2012), and to evaluate the discriminatory power (DP) of spoligotyping, standard 24locus MIRU-VNTR and IS6110-RFLP methods in this setting. The results showed that the main MTB spoligotype families were Beijing (25.3%) and LAM (24.3%), followed by T (22.1%), Ural (11.2%), Haarlem (6.6%) and X superfamily (3.4%). This distribution remained stable over the five consecutive years. 67.6% of MTB isolates were pan-susceptible, and 32.4% were resistant to any drug; multi-drug resistance was found in 5.8% of MTB strains, and 7.6% of MTB isolates were extensively drugresistant. Drug resistance was associated with SIT1, SIT283 and SIT42 genotypes, while SIT1 and SIT42 were overrepresented among multi drugresistant MTB strains. Overall, DP of spoligotyping method alone was 0.8953, while DP of both 24-locus MIRU-VNTR analysis and IS6110 RFLP was higher (DP=0.9846 and 0.9927, respectively), mainly due to the improvement of the resolution for the Beijing strains. In conclusion, this work represents the first comprehensive molecular epidemiological description of TB in Latvia, highlighting the high genetic diversity of MTB strains circulating in Riga and Riga region. In combination with detailed epidemiological data this approach was helpful for the in-depth understanding of epidemiological processes in settings where the Next-Gen sequencing is not available as a routine method.

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