Whirling Disease: Reviews and Current Topics

Modeling Myxobolus cerebralis Infections in Trout: Associations with Habitat Variables

Monica Hiner and Christine M. Moffitt

doi: https://doi.org/10.47886/9781888569377.ch15

ABSTRACT. We obtained data from several sources to explore selected habitat compartments of a more complex epizootic model of factors affecting Myxobolus cerebralis in free-ranging populations of fish. We examined histological sections from branchial and cranial tissues from Yellowstone cutthroat trout Oncorhynchus clarki bouvieri and rainbow trout O. mykiss, naturally exposed to M. cerebralis at nine locations within three river drainages in Idaho, for evidence of characteristic pathology of whirling disease. Mean water temperature during exposure, temperature coefficient of variation, and the density of two groups of benthic macroinvertebrates that can thrive in habitats of high organic content were significantly positively correlated with the mean lesion severity of infected fish. We used stepwise multiple linear regression models to test combinations of variables as predictors of disease severity. Models with average water temperature or average temperature variation during exposure and the density of oligochaetes and chironomids accounted for more than 80% of the variation.