Survey on Perkinsus Species in Manila Clam Ruditapes philippinarum in Korean Waters Using Species-Specific PCR

We investigated possible infection with Perkinsus olseni and/or P. honshuensis in Manila clams in Korean waters using Perkinsus species-specific PCR. Ray’s fluid thioglycollate medium assay revealed that 97.3% of the clams examined were infected with Perkinsus sp., with the mean intensity ranging from 2.2 × 104 to 6.8 × 106 cells/g gill. In the Perkinsus species-specific PCR assay, all the amplified Perkinsus-positive bands were identified as P. olseni, while none of P. honshuensis-specific band was amplified. Our survey results indicate that P. olseni is the main causative agent of perkinsosis in Manila clam populations in Korean waters, while more extensive survey must be carried out.