Infection of protozoan Perkinsus in the short-necked clam (Ruditapes philippinarum) on the Hokkaido [Japan] coastal region and the infection examination
2010
Nishihara, Y., Hokkaido. Central Fisheries Experiment Station, Yoichi (Japan)
The Ray's fluid thioglycollate medium (RFTM) assay technique was used to study Perkinsus infection in the short-necked clam (Ruditapes philippinarum) in the Hokkaido coastal region between 1999 and 2001. Formation conditions for the Perkinsus zoospore were observed, with particular attention to favorable temperature and salinity ranges. The zoospore was then cultured with short-necked clam tissues and experimentally infected into short-necked clam, Japanese scallop (Patinopecten yessoensis), Japanese oyster (Crassostrea gigas), and Ezo abalone (Haliotis discus hannai) at various temperatures. The protozoan was not detected in the Pacific Ocean or the Okhotsk Sea, but it was detected at all tested locations in the Sea of Japan. No effect on zoospore formation was observed to result from variation in salinity (0-3%). In the laboratory, zoospore formation was observed at 20degC and 25degC, but not at 15degC. In the lab portion of the study, however, when Perkinsus infection was attempted at 20degC infection was not confirmed in any of the four tested species. At 25degC, however, infection was confirmed in the short-necked clam.
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