Molecular characterization of Babesia canis strains detected in naturally infected dogs in Lithuania

Abstract

Canine babesiosis caused by Babesia canis is an emerging infectious disease in Europe. In Lithuania it has become quite frequent in the last few years, and an increasing number of cases with a wide variety of clinical signs have been recorded throughout the country. Differences in the virulence of B. canis are associated with observed genetic heterogeneity among B. canis strains. In the present study we aimed to investigate genetic diversity of B. canis strains in Lithuania using PCR-RFLP assay and sequence analysis based on the 18S rRNR and Bc28.1 genes. In total 138 blood samples from dogs suspected of babesiosis were collected in Lithuania during 2016-2017. PCR-RFLP analysis of B. canis 18S rRNR gene identified 2 genotypes, from those predominated less virulent 18S rRNR-A (93.3 %) against more virulent 18S rRNR-B (6.66 %) genotype. Three 18S rRNR genotypes of B. canis were distinguished by sequence analysis. Two group of B. canis strains were detected by analyzing Bc28.1 gene and a total of fifteen single nucleotide polymorphisms were identified by sequence analysis. The majority of the B. canis strains were of the genotype Bc28.1-B (82.1%), followed by genotype Bc28.1-A (17.9 %). The distribution of Bc28.1 genotypes in Lithuania is similar to that obtained in South – West Europe, but different from North – East Europe findings. Our results indicate the presence of different B. canis genotypes in Lithuania and provide the basis for study of the relationship between the genetic structure of B. canis, their geographical distribution, and the form of the disease in dogs.