title: Infecting Pacific Herring with Ichthyophonus sp. in the Laboratory.
abstract: The protistan parasite Ichthyophonus sp. occurs in coastal populations of Pacific Herring Clupea pallasii throughout the northeast Pacific region, but the route(s) by which these planktivorous fish become infected is unknown. Several methods for establishing Ichthyophonus infections in laboratory challenges were examined. Infections were most effectively established after intraperitoneal (IP) injections with suspended parasite isolates from culture or after repeated feedings with infected fish tissues. Among groups that were offered the infected tissues, infection prevalence was greater after multiple feedings (65%) than after a single feeding (5%). Additionally, among groups that were exposed to parasite suspensions prepared from culture isolates, infection prevalence was greater after exposure by IP injection (74%) than after exposure via gastric intubation (12%); the flushing of parasite suspensions over the gills did not lead to infections in any of the experimental fish. Although the consumption of infected fish tissues is unlikely to be the primary route of Ichthyophonus sp. transmission in wild populations of Pacific Herring, this route may contribute to abnormally high infection prevalence in areas where juveniles have access to infected offal.
authors.affiliation: a U.S. Geological Survey, Western Fisheries Research Center, Marrowstone Marine Field Station, 616 Marrowstone Point Road , Nordland , Washington 98358 , USA.
authors.forename: P K
authors.initials: PK
authors.lastname: Hershberger
authors.affiliation: a U.S. Geological Survey, Western Fisheries Research Center, Marrowstone Marine Field Station, 616 Marrowstone Point Road , Nordland , Washington 98358 , USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Hart
authors.affiliation: a U.S. Geological Survey, Western Fisheries Research Center, Marrowstone Marine Field Station, 616 Marrowstone Point Road , Nordland , Washington 98358 , USA.
authors.forename: A H
authors.initials: AH
authors.lastname: MacKenzie
authors.affiliation: a U.S. Geological Survey, Western Fisheries Research Center, Marrowstone Marine Field Station, 616 Marrowstone Point Road , Nordland , Washington 98358 , USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Yanney
authors.affiliation: b U.S. Geological Survey, Western Fisheries Research Center, 6505 Northeast 65th Street , Seattle , Washington 98115 , USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Conway
authors.affiliation: b U.S. Geological Survey, Western Fisheries Research Center, 6505 Northeast 65th Street , Seattle , Washington 98115 , USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Elliott
mesh_terms: D000818:Animals; D005393:Fish Diseases / Q000469:parasitology* / Q000635:transmission; D005399:Fishes; D050298:Mesomycetozoea; D050738:Mesomycetozoea Infections / Q000469:parasitology* / Q000635:transmission