First report of Urosporidium sp., a haplosporidian hyperparasite infecting digenean trematode Parvatrema duboisi in Manila clam, Ruditapes philippinarum on the west coast of Korea.
In this study, we first report on the occurrence of Urosporidium sp., a haplosporidian hyperparasite infecting the trematode, Parvatrema duboisi, which parasitizes Manila clams, Ruditapes philippinarum on the west and south coasts of Korea. The larval P. duboisi infected by the sporocyst stage of Urosporidium sp. demonstrated numerous small yellowish spores in their tissues. The heavily infected metacercariae exhibited degenerate bodies and the larvae were often motionless. Clams heavily infected by the metacercariae of P. duboisi also displayed abnormal golden spots on the mantle tissue. In histology, different life stages of Urosporidium sp. could be identified, including the uni-nucleate, plasmodial, sporogonic stages and the acid fast mature spores released from the cyst. In scanning electron microscopy (SEM), the mature spore exhibited a semi-circular rim around the apical end and the orifice was covered internally with a flap. Loop-like filaments ornamentation was also identified from Urosporidium sp. in SEM, suggesting that Urosporidium sp. found in this study is a new member in the genus. Prevalence of Urosporidium sp.-infected trematodes in this study ranged from 2.5% to 24.0% in April 2010 and the infection was observed from 8 sampling sites out of the 26 sites surveyed on the west and south coasts.
School of Marine Biomedical Science (BK21 PLUS), Jeju National University, 102 Jejudaehakno, Jeju 690-756, Republic of Korea.
Thanh Cuong
TC
Le
School of Marine Biomedical Science (BK21 PLUS), Jeju National University, 102 Jejudaehakno, Jeju 690-756, Republic of Korea.
Hyun-Sil
HS
Kang
School of Marine Biomedical Science (BK21 PLUS), Jeju National University, 102 Jejudaehakno, Jeju 690-756, Republic of Korea.
Hyun-Ki
HK
Hong
West Sea Fisheries Research Institute, National Fisheries Research and Development Institute (NFRDI), Inchon, Republic of Korea.
Kwang-Jae
KJ
Park
School of Marine Biomedical Science (BK21 PLUS), Jeju National University, 102 Jejudaehakno, Jeju 690-756, Republic of Korea. Electronic address: skchoi@jejunu.ac.kr.
Kwang-Sik
KS
Choi
D000818:Animals; D049872:Bivalvia / Q000469:parasitology*; D041602:Haplosporida / Q000469:parasitology*; D008855:Microscopy, Electron, Scanning; D015995:Prevalence; D056910:Republic of Korea; D014200:Trematoda
Hyperparasitism; Korea; Metacercaria; Parvatrema duboisi; Ruditapes philippinarum; Trematoda; Urosporidium sp.