title: Molecular detection of novel Anaplasmataceae closely related to Anaplasma platys and Ehrlichia canis in the dromedary camel (Camelus dromedarius).
abstract: Serological surveys have confirmed Anaplasma marginale and Anaplasma phagocytophilum infections in dromedary camels, but molecular surveys and genetic characterisation of camel-associated Anaplasma species are lacking. In this study, we detected tick-borne Anaplasmataceae in 30 of 100 (30%) healthy dromedary camels screened using a combined 16S rRNA-groEL PCR-sequencing approach. Nucleotide sequencing confirmed Anaplasmataceae genome presence in 28 of the 33 16S rRNA PCR-positive samples, with two additional positive samples, for which 16S rRNA sequence data were ambiguous, being identified by groEL gene characterisation. Phylogenetic analyses of a 1289 nt segment of the 16S rRNA gene confirmed the presence of a unique Ehrlichia lineage and a discrete Anaplasma lineage, comprising three variants, occurring at an overall prevalence of 4% and 26%, respectively. Genetic characterisation of an aligned 559 nt groEL gene region revealed the camel-associated Anaplasma and Ehrlichia lineages to be novel and most closely related to Anaplasma platys and Ehrlichia canis. Based on the confirmed monophyly, minimum pairwise genetic distances between each novel lineage and its closest sister taxon, and the inability to isolate the bacteria, we propose that Candidatus status be assigned to each. This first genetic characterisation of Anaplasmataceae from naturally infected, asymptomatic dromedary camels in Saudi Arabia confirms the presence of two novel lineages that are phylogenetically linked to two pathogenic canid species of increasing zoonotic concern.
authors.affiliation: Department of Zoology & Entomology, University of Pretoria, Private Bag 20, Hatfield 0028, Pretoria, South Africa. Electronic address: ADBastos@zoology.up.ac.za.
authors.forename: Armanda D S
authors.initials: AD
authors.lastname: Bastos
authors.affiliation: KSU Mammals Research Chair, Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
authors.forename: Osama B
authors.initials: OB
authors.lastname: Mohammed
authors.affiliation: KSU Mammals Research Chair, Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; NRF-DST SARChI Chair of Mammal Behavioural Ecology & Physiology, Department of Zoology & Entomology, University of Pretoria, Private Bag 20, Hatfield 0028, Pretoria, South Africa.
authors.forename: Nigel C
authors.initials: NC
authors.lastname: Bennett
authors.affiliation: Department of Zoology & Entomology, University of Pretoria, Private Bag 20, Hatfield 0028, Pretoria, South Africa.
authors.forename: Charalambos
authors.initials: C
authors.lastname: Petevinos
authors.affiliation: KSU Mammals Research Chair, Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia.
authors.forename: Abdulaziz N
authors.initials: AN
authors.lastname: Alagaili
mesh_terms: D000710:Anaplasmataceae / Q000235:genetics / Q000302:isolation & purification*; D000711:Anaplasmataceae Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D000818:Animals; D001483:Base Sequence; D002162:Camelus / Q000382:microbiology*; D005260:Female; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012529:Saudi Arabia / Q000453:epidemiology
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: 16S rRNA; Alphaproteobacteria; Anaplasma; Camelus dromedarius; Ehrlichia; GroEL; Phylogeny; Saudi Arabia; Tick-borne Anaplasmataceae