title: Cofeeding intra- and interspecific transmission of an emerging insect-borne rickettsial pathogen.
abstract: Cat fleas (Ctenocephalides felis) are known as the primary vector and reservoir of Rickettsia felis, the causative agent of flea-borne spotted fever; however, field surveys regularly report molecular detection of this infectious agent from other blood-feeding arthropods. The presence of R. felis in additional arthropods may be the result of chance consumption of an infectious bloodmeal, but isolation of viable rickettsiae circulating in the blood of suspected vertebrate reservoirs has not been demonstrated. Successful transmission of pathogens between actively blood-feeding arthropods in the absence of a disseminated vertebrate infection has been verified, referred to as cofeeding transmission. Therefore, the principal route from systemically infected vertebrates to uninfected arthropods may not be applicable to the R. felis transmission cycle. Here, we show both intra- and interspecific transmission of R. felis between cofeeding arthropods on a vertebrate host. Analyses revealed that infected cat fleas transmitted R. felis to naïve cat fleas and rat fleas (Xenopsylla cheopis) via fleabite on a nonrickettsemic vertebrate host. Also, cat fleas infected by cofeeding were infectious to newly emerged uninfected cat fleas in an artificial system. Furthermore, we utilized a stochastic model to demonstrate that cofeeding is sufficient to explain the enzootic spread of R. felis amongst populations of the biological vector. Our results implicate cat fleas in the spread of R. felis amongst different vectors, and the demonstration of cofeeding transmission of R. felis through a vertebrate host represents a novel transmission paradigm for insect-borne Rickettsia and furthers our understanding of this emerging rickettsiosis.
authors.affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Drive, Baton Rouge, LA, 70803, USA.
authors.forename: Lisa D
authors.initials: LD
authors.lastname: Brown
authors.affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Drive, Baton Rouge, LA, 70803, USA.
authors.forename: Rebecca C
authors.initials: RC
authors.lastname: Christofferson
authors.affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Drive, Baton Rouge, LA, 70803, USA.
authors.forename: Kaikhushroo H
authors.initials: KH
authors.lastname: Banajee
authors.affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Drive, Baton Rouge, LA, 70803, USA.
authors.forename: Fabio
authors.initials: F
authors.lastname: Del Piero
authors.affiliation: Department of Entomology, Louisiana State University Agricultural Center, LSB-413, Baton Rouge, LA, 70803, USA.
authors.forename: Lane D
authors.initials: LD
authors.lastname: Foil
authors.affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Drive, Baton Rouge, LA, 70803, USA.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Macaluso
mesh_terms: D000818:Animals; D058251:Ctenocephalides / Q000382:microbiology*; D007303:Insect Vectors / Q000382:microbiology; D008297:Male; D008809:Mice, Inbred C3H; D008954:Models, Biological; D012282:Rickettsia Infections / Q000635:transmission*; D041161:Rickettsia felis; D058260:Xenopsylla / Q000382:microbiology*
keywords: Ctenocephalides felis; Rickettsia; Xenopsylla cheopis; cofeeding transmission