Whirling disease: host specificity and interaction between the actinosporean stage of Myxobolus cerebralis and rainbow trout Oncorhynchus mykiss
[摘要] ABSTRACT: Scanning electron microscopic studies were conducted on rainbow trout
Oncorhynchus mykiss in the first 60 min after their exposure to the triactinomyxon spores of
Myxobolus cerebralis. The results demonstrated that as early as 1min post exposure the whole process, from the attachment of the triactinomyxon spores to the complete penetration of their sporoplasm germs, had occurred. The triactinomyxon spores sought out the secretory openings of mucous cells of the epidermis, therespiratory epithelium and the buccal cavity of trout and used them as portals of entry. Exposure experiments of the triactinomyxon spores of
M. cerebralis to non-salmonid fish, such as goldfish
Carassius auratus, carp
Cyprinuscarpio, nose
Chondrostoma nasus, medaka
Oryzias latipes, guppy
Poecilia reticulata and also the amphibian tadpole
Rana pipiens as well as to rainbow trout fry indicated a specificity for salmonids. Attempts to activate thetriactinomyxon spores by exposure to mucus prepared from cyprinid and salmonid fish showed no significant differences from those conducted in tap water. The results suggest that the simultaneous presence of both mechano- and chemotactic stimuli wasrequired for finding the salmonid fish host.
