Detection and partial molecular characterization of Rickettsia and Bartonella from southern African bat species

Abstract

In Africa, bats have been implicated in a number of emerging and re-emerging diseases, mostly associated with viral infections – such as caused by rabies-related lyssaviruses, paramyxoviruses and coronaviruses. Whereas most infectious agents reported in bats have been viruses, bacterial species have rarely been reported. The main objective of this study was to identify bacterial species that may circulate in southern African bats by using nucleic acid detection methods. Two bacterial species were targeted: Rickettsia and Bartonella. These were chosen because they are capable of infecting and causing diseases in a wide range of hosts including humans. We evaluated and optimized several polymerase chain reaction (PCR) assays to detect Rickettsia and Bartonella. These included PCRs targeting the citrate synthase gene (gltA) and 16S rRNA gene for Rickettsia and the citrate synthase (gltA) gene for Bartonella. A panel of 354 bat blood samples, collected from different sites in South Africa and Swaziland, were tested using these assays. Rickettsia and Bartonella DNA was detected in 6/354 and 13/354 bats, respectively, and characterized using DNA sequencing. All the Rickettsias were closely related to other Rickettsia species circulating in these areas and all the Bartonellas clustered together, but were distantly related to Bartonella species from the same geographical area. This study reports for the first time the detection of Rickettsia and Bartonella DNA in southern African bats. This finding contributes to the knowledge regarding Rickettsia and Bartonella diversity and host distribution. The epidemiology and transmission pathways of these bacteria in bat populations remains to be elucidated as is the public health importance of the circulation of these potential pathogens in bats. A likely source of infection is unknown, but since bats carry ectoparasites (flies, fleas, ticks and mites); surveillance for these pathogens in ectoparasites should be a first step in elucidating epidemiology and transmission pathways to other hosts including humans. Given the potential for human disease, the surveillance and characterization of these pathogens will be in the interest of good public health practices.