It is vitally important that good quality descriptions of actinosporean stages of myxosporeans are produced since these may prove to have a very important role in the taxonomy and classification of the combined rnyxozoan taxon. Guidelines are therefore presented for the preparation of accurate descriptions of actinosporean stages, and the terminology to be employed in such descriptions is outlined and defined. Actinospore and myxospore should be promoted as terms for the myxosporean and actinosporean spore stages in the myxozoan life cycle.

Abstract. During an experiment to transmit Tetracapsula bryosalmonae Canning, Curry, Feist, Longshaw et Okamura, 1999 to a laboratory-cultured bryozoan, Plumatella repens L. a previously undescribed malacosporean species was noted. This parasite produced sacs of spores in the host that reached 1.2 mm in length. The spores released from the sacs appeared similar in size to the two species of Tetracapsula previously described although slight differences in form were noted. Release of spores from the bryozoans was observed associated with the lophophore of the host. The use of experimental bryozoan cultures for the examination of malacosporeans is described and discussed.

Proliferative kidney disease (PKD) is an economically significant disease caused by the myxozoan parasite Tetracapsula bryosalmonae. Polymerase chain reaction (PCR) protocols using primers specific for the small subunit ribosomal RNA (18S rDNA) gene of the parasite enable detection, however, false positive and negative results can render detection inconclusive. In this study a decontamination protocol was developed, using hydroxylamine hydrochloride (H), to prevent false positives by blocking re‐amplification of carry‐over contaminants. A mimic molecule was also developed and used as a competitive internal standard coamplified with target DNA in PCRs, revealing both true and false negatives. The sensitivity of one new and two existing primer sets was assessed with all primers detecting DNA equivalent to at least eight parasite cells per gram of tissue. This improved PCR protocol canprovide more reliable testing for T. bryosalmonae.

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