Ichthyophonus-like infection in wild amphibians from Québec, Canada.
Myositis associated with infection by Ichthyophonus-like organisms was diagnosed in 35 of 260 (13%) wild amphibians collected in Quebec, Canada, from 1959 to 1964 (n = 30), and 1992 to 1999 (n = 230). Infection was diagnosed in 17 green frogs Rana clamitans, 9 wood frogs R. sylvatica, 4 red-spotted newts Notophthalmus viridescens, 3 bullfrogs R. catesbeiana, 1 spring peeper Pseudacris crucifer, and 1 pickerel frog R. palustris. The spring peeper and one of the bullfrogs were collected in 1964 from the Mont Saint-Hilaire Biosphere Reserve, indicating long-term presence of the organism. Spores of the organisms invaded striated muscle fibers and were associated with variable degrees of granulomatous and eosinophilic inflammation. Infection was considered fatal in 2 green frogs, 1 wood frog, and 1 red-spotted newt. It was considered potentially significant in 3 additional green frogs in which up to 100% of the fibers of some muscles were replaced by spores associated with a severe granulomatous reaction. Ultrastructural features of Ichthyophonus-like spores included a thick trilaminated wall, a paramural cytoplasm, multiple nuclei, oval mitochondria with short tubulo-vesicular cristae and numerous ribosomes. This report represents 4 new host records and shows that ichthyophonosis is enzootic in amphibians from Quebec.
Mikaelian
I
I
Canadian Cooperative Wildlife Health Centre and Centre Québécois sur la Santé des Animaux Sauvages, Saint-Hyacinthe, Québec. igor-mikaelian@idexx.com
Ouellet
M
M
Pauli
B
B
Rodrigue
J
J
Harshbarger
J C
JC
Green
D M
DM
D000663:Amphibians / Q000382:microbiology*; D000818:Animals; D005658:Fungi / Q000502:physiology* / Q000648:ultrastructure; D006054:Goldfish; D008854:Microscopy, Electron / Q000662:veterinary; D018482:Muscle, Skeletal / Q000382:microbiology* / Q000473:pathology; D009181:Mycoses / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D009220:Myositis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D011792:Quebec / Q000453:epidemiology; D013172:Spores, Fungal / Q000648:ultrastructure