title: Evidence for a specific host-endosymbiont relationship between 'Rickettsia sp. genotype RF2125' and Ctenocephalides felis orientis infesting dogs in India.
abstract: BACKGROUND
  Fleas of the genus Ctenocephalides serve as vectors for a number of rickettsial zoonoses, including Rickettsia felis. There are currently no published reports of the presence and distribution of R. felis in India, however, the ubiquitous distribution of its vector Ctenocephalides felis, makes it possible that the pathogen is endemic to the region. This study investigates the occurrence of Rickettsia spp. infection in various subspecies of C. felis infesting dogs from urban areas of Mumbai, Delhi and Rajasthan in India.
  
  
  METHODS
  Individual fleas collected off 77 stray dogs from Mumbai, Delhi and Rajasthan were screened for Rickettsia spp. by a conventional PCR targeting the ompB gene. Further genetic characterisation of Rickettsia-positive fleas was carried out using nested PCR and phylogenetic analysis of partial DNA sequences of the gltA and ompA genes. Ctenocephalides spp. were morphologically and genetically identified by PCR targeting a fragment of cox1 gene.
  
  
  RESULTS
  Overall, 56/77 fleas (72.7%), including 22/24 (91.7%) from Delhi, 32/44 (72.7%) from Mumbai and 2/9 (22.2%) from Rajasthan were positive for Rickettsia DNA at the ompB gene. Sequences of gltA fragments confirmed the amplification of Rickettsia sp. genotype RF2125. The ompA gene of Rickettsia sp. genotype RF2125 was characterised for the first time and shown 96% identical to R. felis. Three species of Ctenocephalides were identified, with the Ctenocephalides felis orientis being the dominant flea species (69/77; 89.6%) in India, followed by Ctenocephalides felis felis (8/77; 10.4%).
  
  
  CONCLUSIONS
  High occurrence of Rickettsia sp. genotype RF2125 in C. felis orientis and the absence of R. felis suggests a specific vector-endosymbiont adaptation and coevolution of the Rickettsia felis-like sp. within subspecies of C. felis.
authors.affiliation: School of Veterinary Science, The University of Queensland, Gatton, Queensland, 4343, Australia. sze.hii@unimelb.edu.au.|Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3052, Australia. sze.hii@unimelb.edu.au.
authors.forename: Sze-Fui
authors.initials: SF
authors.lastname: Hii
authors.affiliation: Faculty of Veterinary Science, The University of Sydney, New South Wales, 2006, Australia. alaw7873@uni.sydney.edu.au.
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Lawrence
authors.affiliation: Safe Food Production Queensland, PO Box 440, Spring Hill, Queensland, 4004, Australia. lcuttell@safefood.qld.gov.au.
authors.forename: Leigh
authors.initials: L
authors.lastname: Cuttell
authors.affiliation: School of Medicine and Pharmacology, The University of Western Australia, Nedlands, Western Australia, 6009, Australia. 20749673@student.uwa.edu.au.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Tynas
authors.affiliation: Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia. azaziah@upm.edu.my.
authors.forename: Puteri Azaziah Megat
authors.initials: PA
authors.lastname: Abd Rani
authors.affiliation: Faculty of Veterinary Science, The University of Sydney, New South Wales, 2006, Australia. jan.slapeta@sydney.edu.au.
authors.forename: Jan
authors.initials: J
authors.lastname: Šlapeta
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3052, Australia. rebecca.traub@unimelb.edu.au.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Traub
mesh_terms: D000818:Animals; D001483:Base Sequence; D058251:Ctenocephalides / Q000145:classification / Q000382:microbiology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004283:Dog Diseases / Q000382:microbiology* / Q000469:parasitology; D004285:Dogs; D005260:Female; D058267:Flea Infestations / Q000662:veterinary*; D005838:Genotype; D007194:India / Q000453:epidemiology; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D012281:Rickettsia / Q000235:genetics / Q000502:physiology*; D012282:Rickettsia Infections / Q000382:microbiology / Q000662:veterinary*; D041161:Rickettsia felis / Q000235:genetics / Q000502:physiology; D017422:Sequence Analysis, DNA; D013559:Symbiosis
chemical_list: D004269:DNA, Bacterial