Members of the order Rickettsiales are small, obligate intracellular bacteria that are vector-borne and can cause mild to fatal diseases in humans worldwide. There is little information on the zoonotic rickettsial pathogens that may be harbored by dogs from rural localities in South Africa. To characterize rickettsial pathogens infecting dogs, we screened 141 blood samples, 103 ticks, and 43 fleas collected from domestic dogs in Bushbuckridge Municipality, Mpumalanga Province of South Africa, between October 2011 and May 2012 using the reverse line blot (RLB) and Rickettsia genus and species-specific quantitative real-time PCR (qPCR) assays. Results from RLB showed that 49% of blood samples and 30% of tick pools were positive for the genus-specific probes for Ehrlichia/Anaplasma; 16% of the blood samples were positive for Ehrlichia canis. Hemoparasite DNA could not be detected in 36% of blood samples and 30% of tick pools screened. Seven (70%) tick pools and both flea pools were positive for Rickettsia spp; three (30%) tick pools were positive for Rickettsia africae; and both flea pools (100%) were positive for Rickettsia felis. Sequencing confirmed infection with R. africae and Candidatus Rickettsia asemboensis; an R. felis-like organism from one of the R. felis-positive flea pools. Anaplasma sp. South Africa dog strain (closely related to Anaplasma phagocytophilum), A. phagocytophilum, and an Orientia tsutsugamushi-like sequence were identified from blood samples. The detection of emerging zoonotic agents from domestic dogs and their ectoparasites in a rural community in South Africa highlights the potential risk of human infection that may occur with these pathogens.

DNA samples from 74 patients with non-malarial acute febrile illness (AFI), 282 rodents, 100 cattle, 56 dogs and 160 Rhipicephalus sanguineus ticks were screened for the presence of Anaplasma phagocytophilum DNA using a quantitative PCR (qPCR) assay targeting the msp2 gene. The test detected both A. phagocytophilum and Anaplasma sp. SA/ZAM dog DNA. Microbiome sequencing confirmed the presence of low levels of A. phagocytophilum DNA in the blood of rodents, dogs and cattle, while high levels of A. platys and Anaplasma sp. SA/ZAM dog were detected in dogs. Directed sequencing of the 16S rRNA and gltA genes in selected samples revealed the presence of A. phagocytophilum DNA in humans, dogs and rodents and highlighted its importance as a possible contributing cause of AFI in South Africa. A number of recently described Anaplasma species and A. platys were also detected in the study. Phylogenetic analyses grouped Anaplasma sp. SA/ZAM dog into a distinct clade, with sufficient divergence from other Anaplasma species to warrant classification as a separate species. Until appropriate type-material can be deposited and the species is formally described, we will refer to this novel organism as Anaplasma sp. SA dog.

Ticks transmit pathogens and harbour non-pathogenic, vertically transmitted intracellular bacteria termed endosymbionts. Almost all ticks studied to date contain 1 or more of Coxiella, Francisella, Rickettsia or Candidatus Midichloria mitochondrii endosymbionts, indicative of their importance to tick physiology. Genomic and experimental data suggest that endosymbionts promote tick development and reproductive success. Here, we review the limited information currently available on the potential roles endosymbionts play in enhancing tick metabolism and fitness. Future studies that expand on these findings are needed to better understand endosymbionts’ contributions to tick biology. This knowledge could potentially be applied to design novel strategies that target endosymbiont function to control the spread of ticks and pathogens they vector.

A cross sectional sero-epidemiological study was conducted on cattle in a communal farming area adjacent to Kruger National Park at a wildlife-livestock interface in South Africa. A total of 184 cattle were screened for exposure to 5 abortifacient or zoonotic pathogens, namely Coxiella burnetii , Toxoplasma gondii , Chlamydophila abortus , Neospora caninum , and Rift Valley fever virus (RVFV) using enzyme-linked immunosorbent assays. In addition, the virus neutralization test was used to confirm the presence of antibodies to RVFV. The seroprevalence of C. burnetii , T. gondii , C. abortus , N. caninum , and RVFV antibodies was 38.0%, 32.6%, 20.7%, 1.6%, and 0.5%, respectively, and varied between locations ( p < 0.001). Seroprevalence of C. burnetii and T. gondii was highly clustered by location (intraclass correlation coefficient [ICC] = 0.57), and that of C. abortus moderately so (ICC = 0.11). Seroprevalence was not associated with sex or age for any pathogen, except for C. abortus , for which seroprevalence was positively associated with age ( p = 0.01). The predominant mixed infections were C. burnetii and T. gondii (15.2%) and C. burnetii , T. gondii , and C. abortus (13.0%). The serological detection of the five abortifacient pathogens in cattle indicates the potential for economic losses to livestock farmers, health impacts to domestic animals, transmission across the livestock-wildlife interface, and the risk of zoonotic transmission. This is the first documentation of T. gondii infection in cattle in South Africa, while exposure to C. burnetii , C. abortus , and N. caninum infections is being reported for the first time in cattle in a wildlife-livestock interface in the country.

Anaplasma species, belonging to the family Anaplasmataceae in the order Rickettsiales, are obligate intracellular bacteria responsible for various tick-borne diseases of veterinary and human significance worldwide. With advancements in molecular techniques, seven formal species of Anaplasma and numerous unclassified species have been described. In Africa, several Anaplasma species and strains have been identified in different animals and tick species. This review aims to provide an overview of the current understanding of the molecular epidemiology and genetic diversity of classified and unclassified Anaplasma species detected in animals and ticks across Africa. The review also covers control measures that have been taken to prevent anaplasmosis transmission on the continent. This information is critical when developing anaplasmosis management and control programs in Africa.

The Bushbuckridge-East community in Mpumalanga Province, South Africa is bordered by nature reserves, including the Manyeleti Game Reserve. Murid rodents are prevalent in both Manyeleti and communal rangelands adjoining the community households. Although rodents are reservoir hosts for a broad range of viral, bacterial and parasitic pathogens, the rodent microbial diversity and transmission of zoonotic agents to humans in the community is understudied. In this study we investigated bacterial diversity in wild and commensal rodents sampled from different habitats. The 16S rRNA gene was amplified from DNA extracted from the blood of 24 wild Mastomys and one Steatomys sp. and subjected to PacBio circular consensus sequencing. As Bartonella species were dominant in the blood microbiome, gltA gene characterization was performed to delineate species. Rodents sampled from peri-urban and communal rangelands had higher proportions of Bartonella spp. [Hlalakahle (77.7%), Gottenburg (47.8%), Tlhavekisa (83.8%)] compared to those from the protected habitat (43.8%). Ehrlichia spp., Anaplasma spp., and Coxiella burnetii were detected at <1% of the sequence reads. Conventional PCR and sequencing validated the detection of Bartonella spp. with the first confirmation of Bartonella mastomydis infection in Mastomys in South Africa. Additionally, 317 mites, 90 fleas, 10 ticks and eight lice were collected from the rodents, providing evidence of possible vectors of the organisms detected. The detection of zoonotic agents in rodents in Bushbuckridge-East community, together with prior serological confirmation of Bartonella and Coxiella in non-malarial acute febrile patients from this community, highlights the possible risks that commensal rodents pose to human health.