DAO 40:131-136 (2000)  -  doi:10.3354/dao040131

Experimental and natural host specificity of Loma salmonae (Microsporidia)

R. W. Shaw1,2,*, M. L. Kent2, A. M. V. Brown3, C. M. Whipps2, M. L. Adamson3

1926520 Twp Rd 512, Spruce Grove, Alberta T7Y 1G1, Canada
2Department of Fisheries and Oceans, Pacific Biological Station, Nanaimo, British Columbia V9R 5K6, Canada
3Department of Zoology, 6270 University Boulevard University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada

ABSTRACT: The microsporidian Loma salmonae (Putz, Hoffman & Dunbar, 1965) Morrison & Sprague, 1981 has caused significant gill disease in Pacific salmon Oncorhynchus spp. Host specificity of the parasite was examined experimentally by per os challenge of selected salmonids and non-salmonids with infective chinook salmon O. tshawytscha gill material. Pink Oncorhynchus gorbuscha and chum salmon O. keta, brown Salmo trutta and brook trout Salvelinus fontinalis, and chinook salmon (controls) were positive, whereas Atlantic salmon Salmo salar and Arctic char Salvelinus alpinus were negative. In addition, no non-salmonids were susceptible to experimental exposure. Wild Pacific salmon species in British Columbia, Canada, were examined for L. salmonae during their freshwater life history stages (smolts, prespawning, spawning). All stages were infected, although infections in smolts were only detectable using a L. salmonae-specific PCR test. Many previous Loma spp. described from Oncorhychus spp. are likely L. salmonae based on host, parasite morphology, and site of infection.


KEY WORDS: Loma salmonae · Microsporidia · Transmission · Host specificity


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