Molecular detection of Babesia microti in laboratory mice from India

Background & objectives: For detection and molecular characterization of Babesia microti in laboratory mice from India. Methods: A total of 625 mice were screened by peripheral blood smear examination and subsequently was confirmed by PCR using a piroplasm conserved primer set (Piro A/B). Nested PCR was done using a species-specific primer targeting the gene encoding the small subunit ribosomal RNA (18S rRNA). The PCR products were cloned, purified and sequenced. A total of 12 isolates were obtained. The sequences were aligned and phylogenetic trees were prepared with other published Babesia spp. sequences. Results: B. microti was detected with a total infection rate of 8.80%. The higher rate of infection was observed by species specific PCR (8.80%) than examined by blood smear (7.20%). Sequence and phylogenetic analysis showed that Babesia species detected in mice were genetically identical to the genotypes of B. microti and can be easily distinguished from other genotypes of Babesia parasites by neighbour joining and maximum likelihood method. Intra-species analysis indicated that all the twelve isolates from six North-Eastern states of India have a close identity but inter-species showed genetic reservoir host for transmission of babesial infection to humans. Interpretation & conclusion: The detection of Babesia microti may suggest that laboratory mice may serve as potential reservoir host for human infection and possibility of innovative way of diagnosing and control of human babesiosis