Molecular and serological evidence of flea-associated typhus group and spotted fever group rickettsial infections in Madagascar

Rado J L Rakotonanahary (1, 2) , Alan Harrison (3) , Alice N Maina (4) , Ju Jiang (4) , Allen L Richards (4) , Minoarisoa Rajerison (1) , Sandra Telfer (3)

1 Unité Peste - Plague Unit [Antananarivo, Madagascar]
2 Université d'Antananarivo
3 IBERS - Institute of Biological, Environmental and Rural Sciences
4 Viral and Rickettsial Diseases Department

Background: Rickettsiae are obligate intracellular bacteria responsible for many febrile syndromes around the world, including in sub-Saharan Africa. Vectors of these pathogens include ticks, lice, mites and fleas. In order to assess exposure to flea-associated Rickettsia species in Madagascar, human and small mammal samples from an urban and a rural area, and their associated fleas were tested. Results: Anti-typhus group (TGR)- and anti-spotted fever group rickettsiae (SFGR)-specific IgG were detected in 24 (39%) and 21 (34%) of 62 human serum samples, respectively, using indirect ELISAs, with six individuals seropositive for both. Only two (2%) Rattus rattus out of 86 small mammals presented antibodies against TGR. Out of 117 fleas collected from small mammals, Rickettsia typhi, a TGR, was detected in 26 Xenopsylla cheopis (24%) collected from rodents of an urban area (n = 107), while two of these urban X. cheopis (2%) were positive for Rickettsia felis, a SFGR. R. felis DNA was also detected in eight (31%) out of 26 Pulex irritans fleas. Conclusions: The general population in Madagascar are exposed to rickettsiae, and two flea-associated Rickettsia pathogens, R. typhi and R. felis, are present near or in homes. Although our results are from a single district, they demonstrate that rickettsiae should be considered as potential agents of undifferentiated fever in Madagascar.

Keywords: Fleas; Madagascar; Murine typhus; Prevalence; Rickettsioses; Rickettsia; Flea-borne spotted fever

Domains: Life Sciences [q-bio]; Human health and pathology; Infectious diseases; Life Sciences [q-bio]; Microbiology and Parasitology; Bacteriology; Life Sciences [q-bio]; Santé publique et épidémiologie

Rado J L Rakotonanahary, Alan Harrison, Alice N Maina, Ju Jiang, Allen L Richards, et al.. Molecular and serological evidence of flea-associated typhus group and spotted fever group rickettsial infections in Madagascar. Parasites & Vectors, 2017, 10 (1), pp.125. ⟨10.1186/s13071-017-2061-4⟩. ⟨pasteur-01652154⟩