Canine babesiosis in Lithuania

Abstract

Canine babesiosis caused by Babesia canis is an emerging infectious disease in Europe. Although previously uncommon, canine babesiosishasbecome quite frequent in Lithuania during thepast decade. In the last few years an increasing number of cases with a wide variety of clinical signs have been recorded throughout the country. Expansion of B. canis in Baltic countries is associated mainly with the expanding range of the main vector - D. reticulatus and international travel. Genetic variability and antigenic variation are important mechanisms for the survival of Babesia parasites in their vertebrate hosts. Difference in the virulence of B. canis are associated with observed genetic heterogeneity among B. canis straisn. We have investigated the genetic diversity and distribution of B. canis strains isolated from naturally infected dogs in Lithuania. Blood samples from dogs suspected of babesiosis were collected across Lithuania during 2014-2017. PCR-RFLP assay and sequence analysis based on 185 rRNR gene and Bc28.1 gene (which encodes a GPlanchored merozoite surface antigen) were used for molecular characterization of B. canis strains. The molecular analysis indicates the presence of genetically heterogenic strains of B. canis in Lithuania: five genotypes of B. canis were identified based on 185 rRNR gene, while ten different Bc28.1 gene sequence variants which divided into three genetically distinct groups were identified. The distribution of B. canis genotypes in Lithuania was not homogenic and showed similarity to North-East and South-West Europe findings.