Molecular Detection of Microorganisms Associated with Small Mammals and Their Ectoparasites in Mali

Abstract

Small mammals are the natural reservoirs for many zoonotic pathogens. Using molecular tools, we assessed the prevalence of bacteria and protozoans in small mammals and their ectoparasites in Faladjè, Bougouni, and Bamoko, Mali. A total of 130 small mammals belonging to 10 different species were captured, of which 74 (56.9%) were infested by ectoparasites, including Laelaps echidnina, Xenopsylla cheopis, Amblyomma variegatum, Rhipicephalus sanguineus sensu lato, and Haemaphysalis spp. nymphs. DNA of Bartonella was found in 14/75 (18.7%), 6/48 (12.5%), and 3/7 (42.8%) small mammals from Faladjè, Bougouni, and Bamako, respectively. In Faladjè, Bartonella DNA was detected in 31/68 (45.6%) of L. echidnina and 14/22 (63.6%) of X. cheopis. In Bougouni, it was found in 2/26 (7.7%) of L. echidnina and 10/42 (23.8%) of X. cheopis. The sequences of Bartonella obtained from small mammals were close to those of Bartonella mastomydis, Bartonella elizabethae, and uncultured Bartonella spp. In Faladjè, Coxiella burnetii DNA was detected in 64.4% (29/45) of Haemaphysalis spp. ticks, 4.5% (2/44) of Mastomys erythroleucus, 12.5% (1/8) of Praomys daltoni, and 1.5% (1/68) of L. echidnina. We found DNA of Wolbachia in X. cheopis from Faladjè and DNA of Rickettsia africae and Ehrlichia ruminantium in Am. variegatum from Bougouni. The results of our study show that several small mammal species harbor and may serve as potential reservoirs of Bartonella spp., likely to play a major role in the maintenance, circulation, and potential transmission of bacteria in Mali. The pathogenicity of these bacteria for humans or animals remains to be demonstrated.

Figure 1.

Map of Mali showing small mammal trapping sites and percentages of animals captured by site. Source: https://fr.wikipedia.org/wiki/Mali#/media/File:Mali_(orthographic_projection).svg; https://fr.wikipedia.org/wiki/Fichier:Mali_cercles.png.

Figure 2.

Maximum-likelihood phylogenetic tree showing the relationships of the Bartonella species studied in this study based on a portion of rpoB gene sequence comparison. The GenBank accession numbers (or the only accession number of the genome) are indicated at the beginning, when the sequences come from Genbank, and the strain or the taxon number is indicated at the end. The sequences were aligned using ClustalW, and phylogenetic inferences were obtained using analysis with TOPALi 2.5 software (Biomathematics and Statistics Scotland, Edinburgh, United Kingdom) within the integrated MrBayes application using the model HKY+I+G. Node percentages are percentages of bootstrap values obtained by repeating the analysis 100 times to generate a majority consensus tree. Bootstrap values less than 70 have been removed from the final tree.