Molecular detection and genetic characterization of coxiella burnetii and bartonella spp infections in small mammals from Moshi, Northern Tanzania

Abstract

Zoonotic pathogens, including Coxiella burnetii and Bartonella species, are known causes of febrile illness globally; however, knowledge on their animal hosts is still limited in many countries including Tanzania. This study aimed to: 1) determine the presence and prevalence of C. burnetii and Bartonella spp in small mammal; 2) identify risk factors for C. burnetii and Bartonella infection in small mammals; and 3) characterize the Bartonella genotypes present in small mammals and their fleas. Spleen samples were tested for the presence of C. burnetii (n=382) and Bartonella spp (n=381) DNA. Overall, 12 (3.1%) of 382 (95% CI: 1.6-5.4) spleens from small mammal tested were positive for C. burnetii DNA. Coxiella burnetii DNA was detected in five (71.4%) of seven (95% CI: 29.0-96.3) small mammal species; Rattus rattus (n=7), Mus musculus (n=1), Acomys wilsoni (n=2), Paraxerus flavovottis (n=1) and Atelerix albiventris (n=1). Eleven (91.7%) of twelve (95% CI: 61.5-99.8) C. burnetii DNA positive were trapped within Moshi Urban District. Overall, 57 (15.0%) of 381 (95% CI: 11.3-18.5) small mammal spleens tested positive for Bartonella DNA. Bartonella DNA was detected in three species (R. rattus n = 54, M. natalensis n = 2 and P. flavovottis n = 1) using qPCR targeting the ssrA gene. Analysis of R. rattus species only for risk of Bartonella infection indicated that Bartonella infection was more likely in reproductively mature as compared to immature small mammal (OR = 3.42, p<0.001). Multiple Bartonella genotypes closely related to known zoonotic Bartonella species were identified in the tested small mammals and fleas. These findings demonstrate that small mammal in Moshi, are hosts of C. burnetii and Bartonella spp and may act as a source of these pathogens to humans and animals. Further studies covering broad range of potential hosts should be considered in order to understand the distribution of these pathogens in other animals. Efforts are needed to determine the clinical impact of C. burnetii and Bartonella infection in humans. Further studies are needed to fully characterize the prevalence, genotypes and diversity of Bartonella spp and C. burnetii in different host populations and their potential impacts on human health.