First record of Rickettsia vini in Ixodes lividus ticks from sand martin (Riparia riparia) nests in Lithuania

Abstract

Introduction: Ixodes lividus (Koch, 1844) ticks are specific parasites of the sand martin Riparia riparia (L.). The distribution range of I. lividus covers Europe and Asia, and it can be found wherever there are sand martin nests. Rickettsia species are widespread in Europe and their distribution is dependent on the distribution of their reservoir or vector hosts. Objectives: In the present study, we report detection of rickettsial DNA in I. lividus ticks that were collected in Lithuania. Materials & methods: A total of 47 nests were collected in 3 different colonies of sand martin in the central part of Lithuania. In total, 2,770 ticks were found and identified as I. lividus based on morphological characteristics. The taxonomic identification of I. lividus was confirmed by sequence analysis of the tick mitochondrial 16S rRNA gene. All ticks were examined for the presence of rickettsial pathogens using PCR amplification of partial gltA, ompA and 17kDa antigen genes of Rickettsia spp. followed by DNA sequencing of positive samples for species identification. Results: Phylogenetic analysis of 16S rRNA sequences revealed six genotypes of I. lividus and indicated that some genotypes were identical to those presented in western and central European populations, while others were unique for Lithuania. We detected DNA of Rickettsia in all stages of I. lividus ticks: in 90.6% of pooled larvae samples and in all examined 7 nymphs, 4 females and in one male specimen. Sequence analysis of partial gltA, ompA and 17kDa antigen genes showed 100% identity with the corresponding Rickettsia vini sequences obtained in GenBank. Conclusion: This study represents the first record of Rickettsia vini in Lithuania and the importance of avian migratory connections, which are associated with the dispersal of I. lividus and rickettsial pathogens in northersn Europe.