Molecular detection and phylogeny of and in naturally infected dogs in Central and Northeast Thailand.

BACKGROUND AND AIM

and are tick-borne, Gram-negative bacteria that cause canine monocytic ehrlichiosis and canine cyclic thrombocytopenia, respectively. These diseases are of great importance and are distributed globally. This study aimed to create new primers for the identification of and in naturally infected dogs using polymerase chain reaction (PCR), DNA sequencing, and phylogenetic analysis using the rDNA and genes.

MATERIALS AND METHODS

In total, 120 blood samples were collected from dogs in three different locations (Saraburi, Buriram, and Nakhon Ratchasima provinces) in Central and Northeast Thailand. The molecular prevalence of and . was assessed using PCR targeting the rDNA and genes. All positive PCR amplicons were sequenced, and phylogenetic trees were constructed based on the maximum likelihood method.

RESULTS

had an overall molecular prevalence of 15.8% based on the rDNA gene, compared to 8.3% based on the gene. In addition, the overall molecular prevalence of using the rDNA gene was 10.8%, while the prevalence rate was 5.8% using the gene. Coinfection was 0.8% in Saraburi province. The partial sequences of the rDNA and genes of and in dogs in Central and Northeast Thailand showed 96.75%-100% identity to reference sequences in GenBank. Phylogenetic analysis of the rDNA and genes revealed that and sequences were clearly grouped into their own clades.

CONCLUSION

This study demonstrated the molecular prevalence of and in Central and Northeast Thailand. The rDNA and genes were useful for the diagnosis of and . Based on the phylogenetic analysis, the partial sequences of the rDNA and genes in and were related to prior Thai strains and those from other countries.