title: Detection of Neorickettsia risticii from various freshwater snail species collected from a district irrigation canal in Nevada County, California.
abstract: This study investigated the role of a district irrigation canal in Nevada County, California, USA, as the point source of infection for Neorickettsia risticii, causative agent of equine neorickettsiosis (EN). A total of 568 freshwater snails comprising Juga spp., Planorbella subcrenata (Carpenter, 1857) (Rough Rams-horn), Physella virgata (Gould, 1855) (Protean Physa) and feces from three horses with EN were collected and tested for N. risticii by real-time PCR. A total of four freshwater snails tested PCR positive for N. risticii. Phylogenetic analysis showed 99.8-100% homology between the different snail and horse N. risticii isolates. This study represents the first report of infection with N. risticii in Planorbella subcrenata and suggests that the irrigation canal was the aquatic environment responsible for the spread of N. risticii.
authors.affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA. npusterla@ucdavis.edu
authors.forename: Nicola
authors.initials: N
authors.lastname: Pusterla
authors.forename: Daniel
authors.initials: D
authors.lastname: Hagerty
authors.forename: Samantha
authors.initials: S
authors.lastname: Mapes
authors.forename: Josh
authors.initials: J
authors.lastname: Vangeem
authors.forename: Lindsey T
authors.initials: LT
authors.lastname: Groves
authors.forename: Mario
authors.initials: M
authors.lastname: Dinucci
authors.forename: Langdon C
authors.initials: LC
authors.lastname: Fielding
authors.forename: Jill C
authors.initials: JC
authors.lastname: Higgins
mesh_terms: D000818:Animals; D002140:California; D041103:Neorickettsia risticii / Q000235:genetics / Q000302:isolation & purification*; D010802:Phylogeny; D012908:Snails / Q000382:microbiology*
keywords: Equine neorickettsiosis; Freshwater snails; Horse; Irrigation canal; Neorickettsia risticii; Potomac horse fever