title: Transmission and passage in horses of the agent of human granulocytic ehrlichiosis.
abstract: The human granulocytotropic ehrlichia and Ehrlichia equi produce similar diseases in their respective host species (humans, horses). Currently, the phylogenetic and biologic relationships of these 2 uncultured pathogens remain unclear. Previous studies have revealed nucleotide sequence similarity approaching identity at the level of the 16S ribosomal RNA gene. To investigate the biologic similarities of these 2 ehrlichiae, the susceptibility of horses to the human agent was tested by intravenous inoculation of infected human blood. The results demonstrate that the human granulocytotropic ehrlichia produces a disease in the horse indistinguishable from that caused by E. equi, providing biologic evidence that these 2 organisms are highly related and potentially conspecific. It is possible that cases of human illness now attributed to human granulocytotropic ehrlichia may in fact be caused by 1 or more strains of an ehrlichia known chiefly as an equine pathogen.
authors.affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis 95616-8737, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Madigan
authors.forename: P J
authors.initials: PJ
authors.lastname: Richter
authors.forename: R B
authors.initials: RB
authors.lastname: Kimsey
authors.forename: J E
authors.initials: JE
authors.lastname: Barlough
authors.forename: J S
authors.initials: JS
authors.lastname: Bakken
authors.forename: J S
authors.initials: JS
authors.lastname: Dumler
mesh_terms: D000368:Aged; D000818:Animals; D001483:Base Sequence; D001772:Blood Cell Count; D004275:DNA, Ribosomal / Q000235:genetics; D004536:Ehrlichia / Q000145:classification* / Q000235:genetics / Q000254:growth & development; D016873:Ehrlichiosis / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D005260:Female; D005334:Fever; D006098:Granulocytes / Q000382:microbiology* / Q000473:pathology; D006734:Horse Diseases / Q000382:microbiology*; D006736:Horses; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000382:microbiology / Q000473:pathology; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S