TABLE 3

Detection of 12 bacterial OTUs in the four wild-rodent species sampled in Senegal: biology and pathogenicity of the corresponding bacterial genus

OTU of interest (genus level)Closest speciesa(% identity in GenBank)No. of positive wild rodents (n = 704)bBiology and epidemiology
Mastomys erythroleucus (n = 219)Mastomys natalensis (n = 93)Mus musculus (n = 203)Rattus rattus (n = 189)
Bartonella Undetermined607316 Bartonella spp. are intracellular fastidious hemotropic Gram-negative organisms identified in a wide range of domestic and wild mammals and transmitted by arthropods. Several rodent-borne Bartonella species have emerged as zoonotic agents, and various clinical manifestations are reported, including fever, bacteremia and neurological symptoms (82).
Borrelia B. crocidurae (100)21086 Borrelia is a genus of spiral Gram-negative bacteria of the spirochete phylum. These bacteria are obligate parasites of animals and are responsible for relapsing fever borreliosis, a zoonotic disease transmitted by arthropods (ticks and lice). This disease is the most frequent human bacterial disease in Africa. West Africa, including Senegal, is a region of endemicity for disease caused by B. crocidurae, and B. duttonii and B. recurrentis have been reported in Central, southern and East Africa (50).
B. duttonii (100)
B. recurrentis (100)
Ehrlichia Ca. Ehrlichia khabarensis” (100)400128The genus Ehrlichia includes five species of small Gram-negative obligate intracellular bacteria. The life cycle includes the reproduction stages taking place in both ixodid ticks, acting as vectors, and vertebrates. Ehrlichia spp. can cause a persistent infection in the vertebrate hosts, which thus become reservoirs of infection. A number of new genetic variants of Ehrlichia have been recently detected in rodent species (e.g., “Ca. Ehrlichia khabarensis”) (51).
Mycoplasma_Otu_1 M. haemomuris (96)2842301 Mycoplasma is a genus that includes over 100 species of bacteria that lack of a cell wall around their cell membrane. Mycoplasma coccoides and Mycoplasma haemomuris are blood parasites of wild and laboratory rodents. A new closely related species (AB752303) was recently isolated from brown rats (45). These species are commonly referred as “hemoplasmas.” Hemoplasmas have been detected within the erythrocytes of cats, dogs, pigs, rodents, and cattle, in which they may cause anemia. There have been sporadic reports of similar infections in humans, but these infections have been poorly characterized (49).
Mycoplasma_Otu_2 M. sp. nov. (100) (GenBank accession no. AB752303)00090
Mycoplasma_Otu_3 M. haemomuris (93)934011
Mycoplasma_Otu_4 M. coccoides (96)00018
Mycoplasma_Otu_5 M. coccoides (95)3800
Mycoplasma_Otu_6 M. coccoides (97)31300
Orientia O. chuto (100)02460 Orientia is a genus of obligate intracellular Gram-negative bacteria found in mites and rodents. Orientia tsutsugamushi is the agent of scrub typhus in humans. This disease, one of the most underdiagnosed and underreported febrile illnesses requiring hospitalization, has an estimated 10% fatality rate unless treated appropriately. A new species, Orientia chuto, was recently characterized in sick patients from the Arabian Peninsula, and new Orientia haplotypes have been identified in France and Senegal (9).
O. tsutsugamushi (98)
Rickettsia R. typhi (100)1001 Rickettsia is a genus of obligate intracellular Gram-negative bacteria found in arthropods and vertebrates. Rickettsia spp. are symbiotic species transmitted vertically in invertebrates, and some are pathogenic invertebrates. Infections by Rickettsia species of the typhus group result in many human diseases, including murine typhus, which is caused by Rickettsia typhi and transmitted by fleas (52).
Streptobacillus S. moniliformis (100)10105 Streptobacillus is a genus of aerobic, Gram-negative facultative anaerobe bacteria, which grow in culture as rods in chains. Streptobacillus moniliformis is common in rats and mice and is responsible of the streptobacillosis form of rat-bite fever, the Haverhill fever. This zoonosis begins with high prostrating fevers, rigors (shivering), headache, and polyarthralgia (joint pain). Left untreated, rat-bite fever has a mortality rate of approximately 10% (53).
  • a Based on phylogenetic analysis; see Fig. S4 in the supplemental material.

  • b n, number of rodents screened and analyzed.