Factors influencing the distribution of Myxobolus cerebralis, the causative agent of whirling disease, in the Cache la Poudre River, Colorado

Diseases of Aquatic Organisms

M. Brady Allen¹  Eric P. Bergersen¹ 

关键词: Salmonid whirling disease;    Myxobolus cerebralis;    Tubifex tubifex;    Trout rearing unit;   

DOI  :  10.3354/dao049051

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Oligochaetes, triactinomyxons (TAMs), and age-0 trout were sampled in the upper Cache la Poudre River, Colorado, to determine the distribution of Myxobolus cerebralis during 1997 and 1998. Densities of the intermediate host, theoligochaete Tubifex tubifex, were 3.5 orders of magnitude higher in the M. cerebralis-infected Poudre Rearing Unit (PRU) trout rearing ponds than at any of the river sampling reaches. Oligochaetes, including T. tubifex, were rare inthe river (1 oligochaete m^-2), except in a few stream side alcoves and eddies (50 oligochaete m^-2). Species composition of oligochaetes in the river reaches was more diverse than in the PRU. Tubifex tubifex constituted 50% orless of the oligochaete community in the river and 98% in the PRU. Infection rates of T. tubifex were 1% in the area above the PRU, 2% in the PRU, and 6% below the PRU. An increased M. cerebralis intensity of infection in age-0 trout belowthe PRU could not be attributed entirely to the high numbers of TAMs in its effluent (3.7 TAMs l^-1). Low densities of TAMs ranging from 0 to 0.2 TAMs l^-1 were found in the river reaches, yet nearly all of the age-0 trout wereinfected soon after emergence. This suggests that very few TAMs, as measured by filtration, need be present in the water column to bring about infection in the majority of trout present. This also indicates that the parasite can persist and potentiallycause reduced juvenile trout recruitment in cold, oligotrophic, sediment poor, high-gradient streams.

【 授权许可】

Unknown