Epidemiological studies worldwide have reported a high prevalence and a great diversity of Bartonella species, both in rodents and their flea parasites. The interaction among Bartonella, wild rodents, and fleas reflects a high degree of adaptation among these organisms. Vertical and horizontal efficient Bartonella transmission pathways within flea communities and from fleas to rodents have been documented in competence studies, suggesting that fleas are key players in the transmission of Bartonella to rodents. Exploration of the ecological traits of rodents and their fleas may shed light on the mechanisms used by bartonellae to become established in these organisms. The present review explores the interrelations within the Bartonella-rodent-flea system. The role of the latter two components is emphasized.

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Bartonella are emerging and re-emerging pathogens affecting humans and a wide variety of animals including rodents. Horizontal transmission of Bartonella species by different hematophagous vectors is well acknowledged but vertical transmission (from mother to offspring) is questionable and was never explored in fleas. The aim of this study was to investigate whether the rodent flea, Xenopsylla ramesis, can acquire native Bartonella from wild rodents and transmit it transovarially. For this aim, Bartonella-free laboratory-reared X. ramesis fleas were placed on six naturally Bartonella-infected rodents and six species-matched Bartonella-negative rodents (three Meriones crassus jirds, two Gerbillus nanus gerbils and one Gerbillus dasyurus gerbil) for 7 days, 12-14h per day. The fleas that were placed on the Bartonella-positive rodents acquired four different Bartonella genotypes. Eggs and larvae laid and developed, respectively, by fleas from both rodent groups were collected daily for 7 days and molecularly screened for Bartonella. All eggs and larvae from both groups were found to be negative for Bartonella DNA. Interestingly, two of five gut voids regurgitated by Bartonella-positive fleas contained Bartonella DNA. The naturally infected rodents remained persistently infected with Bartonella for at least 89 days suggesting their capability to serve as competent reservoirs for Bartonella species. The findings in this study indicate that X. ramesis fleas can acquire several Bartonella strains from wild rodents but cannot transmit Bartonella transovarially.

BackgroundBartonellae are fastidious bacteria causing persistent bacteremia in humans and a wide variety of animals. In recent years there is an increasing interest in mammalian bartonelloses in general and in rodent bartonelloses in particular. To date, no studies investigating the presence of Bartonella spp. in rodents and ectoparasites from Nigeria were carried out.Methodology/Principal FindingsThe aim of the current study was to investigate the presence of Bartonella spp. in commensal rodents and their ectoparasites in Nigeria. We report, for the first time, the molecular detection of Bartonella in 26% (46/177) of commensal rodents (Rattus rattus, R. norvegicus and Cricetomys gambianus) and 28% (9/32) of ectoparasite pools (Xenopsylla cheopis, Haemolaelaps spp., Ctenophthalmus spp., Hemimerus talpoides, and Rhipicephalus sanguineus) from Nigeria. Sequence analysis of the citrate synthase gene (gltA) revealed diversity of Bartonella spp. and genotypes in Nigerian rodents and their ectoparasites. Bartonella spp. identical or closely related to Bartonella elizabethae, Bartonella tribocorum and Bartonella grahamii were detected.Conclusions/SignificanceHigh prevalence of infection with Bartonella spp. was detected in commensal rodents and ectoparasites from Nigeria. The Bartonella spp. identified were previously associated with human diseases highlighting their importance to public health. Further studies need to be conducted to determine whether the identified Bartonella species could be responsible for human cases of febrile illness in Nigeria.

: Ticks are vectors of important pathogens of human and animals. Therefore, their microbial carriage capacity is constantly being investigated. The aim of this study was to characterize the diversity of domestic animal pathogens in ticks collected from vegetation and the ground, from different parts of Israel. Non-engorged questing adult ticks were collected from 13 localities. A total of 1196 ticks in 131 pools-83 pools of Rhipicephalus turanicus and 48 of Rhipicephalus sanguineus (with two to ten ticks per pool)-were included in this study. In addition, 13 single free-roaming Hyalomma spp. ticks were collected. Screening by molecular techniques revealed the presence of Ehrlichia canis, Anaplasma platys, Anaplasma bovis and Babesia canis vogeli DNA in R. turanicus ticks. E. canis, A. bovis, B. canis vogeli and Candidatus Midichloria mitochondrii DNA sequences were detected in R. sanguineus ticks. Candidatus Midichloria mitochondrii DNA was also detected in Hyalomma spp. ticks. Neither Hepatozoon spp. nor Bartonella spp. DNA was detected in any of the ticks examined. This study describes the first detection of E. canis in the tick R. turanicus, which may serve as a vector of this canine pathogen; E. canis was the most common pathogen detected in the collected questing ticks. It also describes the first detection of A. bovis and Candidatus Midichloria mitochondrii in Israel. To the best of the author's knowledge, this is the first report describing the detection of DNA of the latter two pathogens in R. sanguineus, and of A. bovis in R. turanicus.