High prevalence of vector-borne protozoa and bacteria in dogs from Chad determined using a targeted next-generation sequencing approach

Data on vector-borne pathogens infecting dogs from sub-Saharan Africa is limited. In this study, we assessed the prevalence of VBPs, their associated risk factors, and pathogen interactions in domestic dogs. Whole blood samples were obtained for 1202 apparently healthy dogs in Chad from September to October 2021, and nucleic acids were extracted and then subjected to a targeted next-generation sequencing (tNGS) assay for detection of 15 VBPs. Overall, 88.7% of the dogs were positive for at least one pathogen, and 62.9% were coinfected with two or more VBPs. The most frequent pathogen detected was Hepatozoon canis in 62.4% of the dogs, Mycoplasma haemocanis in 59.2%, Anaplasma platys in 29.2%, Candidatus Mycoplasma haematoparvum in 21.2%, Ehrlichia canis in 20.3%, Babesia vogeli in 2.0% and Candidatus Mycoplasma turicensis in 1.5%. While most of the dogs (62.9%) were co-infected with two or more VBPs, having an infection with three pathogens (30.8%) was more common. According to multivariable logistic regression analysis, being a senior dog and residing in Chari Baguirmi south were identified as potential risk factors for infection by most of the pathogens. Network analyses revealed complex interactions suggesting facilitative associations among VBPs. These results are useful in expanding the knowledge of VBPs in Africa and establishing a baseline for downstream studies into hemotropic mycoplasmas.