Haemoparasites of free-roaming dogs associated with several remote Aboriginal communities in Australia

The aim of this study was to determine the prevalence of canine haemoplasma infection in the blood of free-roaming dogs from several remote Aboriginal communities in central and northern Australia. A further aim was to determine if such infections were associated with the tick-borne haemoparasites Babesia/Theileria spp. and Anaplasma platys, both of which are prevalent in the study areas. Surveys of canine haemoplasma prevalence have not been reported from Australia, although they are thought to have the same vector (Rhipicephalus sanguineus) as B. canis vogeli and A. platys. EDTA-blood was collected from 39 free-ranging dogs between 2008 and 2010 from 4 Aboriginal communities in central and northern Australia. Genomic DNA was purified from each sample using a commercial kit and subjected to an Anaplasmataceae family conventional PCR (cPCR), an A. platys real-time quantitative PCR (qPCR), a Babesia/Theileria spp. cPCR, species-specific qPCRs for each of Mycoplasma haemocanis and ‘Candidatus Mycoplasma haematoparvum’ each duplexed with a canine internal control gene (GAPDH), and panhaemoplasma qPCRs. Discordant haemoplasma results were subjected to DNA sequencing. All samples contained acceptable levels of canine GAPDH DNA (threshold cycle: 18.2 to 23.3). Of the 39 dogs, 20 (51%) were infected with A. platys, 17 (44%) with Babesia/Theileria spp., 17 (44%) with M. haemocanis and eight (21%) with ‘Ca. M. haematoparvum’. Sequencing of a 600 base-pair 16S rRNA gene fragment amplified from two dogs that were qPCR positive on the panhaemoplasma assay, but negative on the M. haemocanis and ‘Ca. M. haematoparvum’ qPCRs, showed that they were infected with a novel haemoplasma species. Whilst Babesia/Theileria spp., A. platys and haemoplasmas were all detected in dogs from all four communities, comparison of prevalence of infection between the communities revealed significant differences. Haemoplasma prevalence was highest (73%, 16/22) in central Australia and lowest (22%, 2/9) in north-western Australia (p=0.017; Fisher's exact test). In contrast, Babesia/Theileria spp. prevalence was low in central Australia (18%, 4/22) but higher (66%, 6/9) in north-western Australia (p=0.003; Fisher's exact test). Anaplasma platys prevalence was 36% (8/22) in central Australia, as compared to 78% (7/9) in north-western Australia (p=0.054; Fisher’s exact test). This is the first time M. haemocanis and ‘Ca. M. haematoparvum’ have been documented in Australian dogs. In addition, a novel haemoplasma species was identified using a panhaemoplasma qPCR screen. The differences in infection distribution warrants further investigation.