Communications: Experimental Production of Proliferative Gill Disease in Channel Catfish Exposed to a Myxozoan-Infected Oligochaete,<i>Dero digitata</i>

Abstract

Specific-pathogen-free fry of channel catfish Ictalurus punctatus raised in well water were exposed to Dero digitata (an oligochaete) collected from ponds where catfish have had proliferative gill disease (PGD) and where D. digitata is known to be infected with the triactinomyxid myxozoan Aurantiactinomyxon sp. These fry developed gill lesions and parasites characteristic of PGD. Fry exposed to suspensions of mature Aurantiactinomyxon spores obtained from squashes of infected D. digitata also developed PGD. Fry exposed to oligochaetes other than Dero spp., non-oligochaete benthic macroinvertebrates, or suspensions of squashes of D. digitata without identifiable myxozoans did not develop PGD.