Infected Donor Biomass and Active Feeding Increase Waterborne Transmission of Ichthyophonus sp. to Rainbow Trout Sentinels
| Autor: | S. E. LaPatra, Richard M. Kocan |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Mesomycetozoea Infections Zoology Pilot Projects Aquatic Science Biology Predation 03 medical and health sciences Fish Diseases Ingestion Waterborne transmission Animals Biomass Biomass (ecology) Ecology Transmission (medicine) Ichthyophonus 04 agricultural and veterinary sciences 030108 mycology & parasitology biology.organism_classification Specific Pathogen-Free Organisms Trout Oncorhynchus mykiss 040102 fisheries 0401 agriculture forestry and fisheries Rainbow trout Sentinel Surveillance |
| Zdroj: | Journal of aquatic animal health. 28(2) |
| ISSN: | 1548-8667 |
| Popis: | The precise nature of Ichthyophonus sp. transmission among wild fishes has eluded description for over a century. Transmission among piscivores is direct, via ingestion of infected prey, but there is also evidence for waterborne transmission between infected and uninfected individuals. Transmission among planktivores is believed to be via a waterborne infectious cell, but definitive proof of this mechanism has not been forthcoming. To explore possible mechanisms of transmission we used Rainbow Trout Oncorhynchus mykiss as a model system and examined the consequence of housing infected donor fish with uninfected (sentinel) fish, without physical contact. We examined two variables linked to transmission: (1) feeding and nonfeeding sentinel fish, and (2) biomass of infected donor fish. Specific-pathogen free sentinel trout were placed in fine-mesh baskets suspended in tanks containing varying numbers of larger Ichthyophonus-infected donor fish and held for 10 weeks, during which time they were examined by in vitro explant culture for the presence of Ichthyophonus. Treatment groups consisted of fed and unfed sentinels housed with infected donors of increasing biomass. After 10 weeks infection prevalence in fed sentinels was significantly higher than in unfed sentinels, and Ichthyophonus was detected earlier in fed fish than in unfed fish. There was no correlation between infection prevalence and donor biomass in fed sentinels, but there was a strong correlation between infection prevalence and increasing donor biomass in unfed sentinels. These data suggest that Ichthyophonus is maintained in wild fish populations by two distinct mechanisms: (1) waterborne infectious cells ingested directly from the water by planktivores, and (2) both infected prey and waterborne infectious cells ingested by piscivores. Received November 13, 2015; accepted February 13, 2016. |
| Databáze: | OpenAIRE |
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