title: Attempted transmission of Ehrlichia risticii (Rickettsiaceae) with Stomoxys calcitrans (Diptera: Muscidae).
abstract: Experimental transmission of Ehrlichia risticii, the causal agent of Potomac horse fever, was attempted with adult stable flies, Stomoxys calcitrans, (L.) using two feeding schedules. In schedule A, a set of 140 flies was allowed to feed once on an experimentally infected donor pony and once 24 h later on a recipient pony. A different set of flies was used each day for a 12-d period. In schedule B, 240 flies were allowed to feed once daily for 12 consecutive d on the donor pony followed by five consecutive daily feedings on the recipient pony. E. risticii was isolated from the blood of the experimentally infected pony during the entire fly-feeding schedule. The recipient pony did not develop clinical signs of Potomac horse fever and remained seronegative to E. risticii up to 60 d after the last stable fly feeding. Mice injected intraperitoneally with emulsions of schedule A and B stable flies were seronegative for E. risticii 30 d after inoculation, and ehrlichial organisms were not demonstrated in impression smears from the digestive tracts of the flies. The stable fly did not transmit E. risticii under these experimental conditions.
authors.affiliation: Department of Entomology, University of Kentucky, Lexington 40546-0091.
authors.forename: J G
authors.initials: JG
authors.lastname: Burg
authors.forename: A W
authors.initials: AW
authors.lastname: Roberts
authors.forename: N M
authors.initials: NM
authors.lastname: Williams
authors.forename: D G
authors.initials: DG
authors.lastname: Powell
authors.forename: F W
authors.initials: FW
authors.lastname: Knapp
mesh_terms: D000818:Animals; D004536:Ehrlichia / Q000502:physiology*; D006734:Horse Diseases / Q000635:transmission*; D006736:Horses; D007303:Insect Vectors / Q000382:microbiology*; D009117:Muscidae / Q000382:microbiology*; D012288:Rickettsiaceae Infections / Q000635:transmission / Q000662:veterinary*