Current distribution and the diversity of Babesia canis strains in Europe

Abstract

Babesia canis is intraerythrocytic protozoan blood parasites that are transmitted by the main vector – Dermacentor reticulatus ticks to dogs and cause canine babesiosis. Canine babesiosis is an infectious disease circulating worldwide. Due to expansion of D. reticulatus ticks to the new, earlier non-endemic areas, canine babesiosis have spread and clinical cases have been reported from central and northern parts of Europe. Canine babesiosis is clinically classified into uncomplicated and complicated forms. Clinical symptoms range from transient anorexia to a complex syndrome in which multiple organ systems could be affected. It was suggested, that differences in the clinical manifestations of disease may reflect different Babesia strains. Statistically significant differences in clinical signs between genetically diverse groups of B. canis have been detected, and functional antigenic differences between B. canis strains have been indicated. The first cases of canine babesiosis in Lithuania were recorded and confirmed by microscopic analysis in the beginning of 21th century. During the past decade canine babesiosis has become quite frequent in Lithuania. We have analyzed blood samples from dogs showing clinical signs of babesiosis and D. reticulatus ticks for the presence of babesial parasites. Sequence analysis showed that B. canis isolates from dogs and ticks were heterogenic. Based on observed two nucleotides substitution (GA→AG) in 18S rRNA gene sequences of B. canis isolates, two genotypes were distinguished in dogs and three genotypes in D. reticulatus ticks. Our study demonstrates the presence of genetically diverse B.canis strains in Lithuania and show the necessity to use a molecular analysis for an accurate diagnosis of canine babesiosis. Such information will help to ensure an effective therapy, and to promote disease control program in Lithuania. [...]