A simple technique to concentrate the protozoan Mikrocytos mackini, causative agent of Denman Island Disease in oysters

This report describes a simple filtration technique to isolate the parasite Mikrcytos mackini from oyster tissue. The technique is based on successive filtration through filter papers and polycarbonate membrane filters of dec reasing mesh using a low vacuum (<8 cm Hg). This technique allows for the r ecovery of about 1 x 10(8) parasites (microcells) from about 2 g of heavily infected oyster tissue. About 99% of the particulate material in the final preparation consisted of intact M. mackini.