A STANDARDIZED METHOD FOR THE IN-VIVO MAINTENANCE OF CRYPTOCARYON IRRITANS (CILIOPHORA) USING THE GRAY MULLET CHELON LABROSUS AS AN EXPERIMENTAL HOST

Experimental primary infections with Cryptocaryon irritans were succes sfully established in mullet following exposure to theronts and mainta ined for up to 34 successive cycles in this host. Fish were exposed to measured numbers of theronts collected within 4 hr of excystment. Fre e-swimming trophonts and reproductive cysts were maintained in wells o f tissue culture plates containing sterilized seawater and subjected t o a photoperiod of 12 hr light: 12 hr dark. Excystment was found to be asynchronous over a period from 84 hr to 35 days. The procedure provi ded at least a 10-fold yield of parasite material per cycle of transmi ssion.