title: Molecular detection of an Ehrlichia-like agent in rainbow trout (Oncorhynchus mykiss) from Northern California.
abstract: Ehrlichia DNA was identified by nested PCR in rainbow trout (Oncorhynchus mykiss) collected from a creek in northern California where Potomac horse fever is endemic. Ehrlichia DNA was found in tissues from several organs including the gills, heart, spleen, liver, kidneys and intestine of trout and from three different adult digenetic trematodes (Deropegus sp., Crepidostomum sp., Creptotrema sp.) parasitizing the gallbladder and/or the intestine of the trout. Sequencing of PCR-amplified DNA from the 16S rRNA gene indicated that the source organism was most closely related to the sequences of E. risticii (level of sequence similarity 96.0%), the SF agent (95.9%), E. sennetsu (95.8%), and Neorickettsia helminthoeca (95.3%). The data suggest that trout and parasitic trematodes may be involved in the epidemiology of an Ehrlichia-like agent belonging to the E. sennetsu genogroup. Whether the fish agent infects horses, dogs, or human beings, and whether it causes disease, remain to be determined.
authors.affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA. npusterla@ucdavis.edu
authors.forename: N
authors.initials: N
authors.lastname: Pusterla
authors.forename: E
authors.initials: E
authors.lastname: Johnson
authors.forename: J
authors.initials: J
authors.lastname: Chae
authors.forename: E
authors.initials: E
authors.lastname: DeRock
authors.forename: M
authors.initials: M
authors.lastname: Willis
authors.forename: R P
authors.initials: RP
authors.lastname: Hedrick
authors.forename: J E
authors.initials: JE
authors.lastname: Madigan
mesh_terms: D000818:Animals; D002140:California; D004269:DNA, Bacterial / Q000032:analysis; D004199:Disease Vectors; D004536:Ehrlichia / Q000302:isolation & purification*; D016873:Ehrlichiosis / Q000473:pathology / Q000635:transmission / Q000662:veterinary*; D005393:Fish Diseases / Q000473:pathology*; D006734:Horse Diseases / Q000209:etiology / Q000382:microbiology; D006736:Horses; D017686:Oncorhynchus mykiss / Q000382:microbiology / Q000469:parasitology*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D014200:Trematoda / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial