Pathogen Detection in Ornithodoros sonrai Ticks and Invasive House Mice Mus musculus domesticus in Senegal

Abstract

Ornithodoros sonrai (O. sonrai) ticks are the only known vectors of Borrelia crocidurae, an agent of tick-borne relapsing fever (TBRF) borreliosis. Rodents serve as principal natural reservoirs for Borrelia. Our research objective was to detect TBRF Borrelia and other zoonotic bacterial infections in ticks and in house mice Mus musculus domesticus, an invasive species currently expanding in rural northern Senegal. Real-time and conventional PCR were utilized for detecting Borrelia and other bacterial taxa. The analyses were performed on 253 specimens of O. sonrai and 150 samples of brain and spleen tissue from rodents. Borrelia crocidurae was found in one O. sonrai tick and 18 Mus musculus domesticus samples, with prevalences of 0.39 percent and 12 percent, respectively, as well as Ehrlichia sp. in one Mus musculus domesticus. Further, we were able to detect the presence of a potentially infectious novel species belonging to the Anaplasmataceae family for the first time in O. sonrai ticks. More attention should be paid to the house mouse and O. sonrai ticks, as they can be potential hosts for novel species of pathogenic bacteria in humans.

Keywords: Anaplasmataceae; Borrelia crocidurae; Mus musculus domesticus; Ornithodoros sonrai; Senegal.

Figure 1

Location of the Dodel commune in the Saint-Louis region in Senegal.

Figure 2

Anaplasmataceae maximum-likelihood phylogenetic tree targeting the partial 513-bp 23S gene.

Figure 3

Anaplasmataceae maximum-likelihood phylogenetic tree targeting the partial 345 bp 16S gene.

Figure 4

Ehrlichia spp. maximum-likelihood phylogenetic tree targeting the partial 633-bp groEL gene.