Molecular epidemiology and multilocus characterization of canine hemoplasmas in Thailand reveal the first 23S rRNA gene sequences of 'Candidatus Mycoplasma haematoparvum'.

Hemotropic Mycoplasma spp., also known as hemoplasmas, are blood-borne pathogens that infect red blood cells and can cause hemolytic anemia in mammals, including dogs. Mycoplasma haemocanis (Mhc) and 'Candidatus Mycoplasma haematoparvum' (CMhp) are the two most common canine hemoplasma species. However, molecular epidemiological data and information on their genetic diversity remain scarce in Thailand. This study investigated hemoplasma PCR positivity in 472 client-owned dogs from Bangkok and Nakhon Pathom and 199 community dogs from Chiang Mai using a polymerase chain reaction (PCR) assay targeting the 16S rRNA gene. The 23S rRNA and RNase P RNA (rnpB) genes were additionally amplified from positive samples for multilocus characterization. Overall, 48 of 671 dogs were PCR-positive (7.2%; 95% confidence interval: 5.4%-9.3%). PCR positivity was higher in the community-dog/Chiang Mai cohort than in the client-owned cohorts; however, dog type and sampling location were fully confounded, and these comparisons should therefore be interpreted descriptively. Sequence analyses identified Mhc and CMhp. Sequence data suitable for analysis at both the 16S and 23S rRNA genes were obtained from 29 positive samples, and rnpB sequences were obtained from nine of these samples. To the best of our knowledge, this study provides the first 23S rRNA gene sequences of CMhp; no homologous CMhp 23S rRNA gene sequence was available in GenBank for direct comparison.