Itoh Naoki, Momoyama Kazuo, Ogawa Kazuo
Laboratory of Fish Diseases, Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan.
J Invertebr Pathol. 2005 Mar;88(3):201-6. doi: 10.1016/j.jip.2004.12.001. Epub 2005 Mar 17.
Recently, natural stocks of the Manila clam, Venerupis (=Ruditapes) philippinarum, have been drastically reduced in Japan. To clarify the reason for this decline in number, clams were sampled monthly from Yamaguchi and processed for histological observations, during which three protozoan parasites were discovered. Transmission electron microscopy revealed that these parasites were unidentified haplosporidian in the connective tissues, Marteilia sp. in the digestive gland and Marteilioides sp. in the oocytes. Histopathological observations suggest that Marteilia sp. and Marteilioides sp. were not pathogenic to the host. However, infection with a haplosporidian may have a negative impact on the clams. The prevalence of these parasites was low and further investigations should be undertaken to clarify their taxonomic status and establish any pathogenicity to clams.
最近，日本菲律宾蛤仔（Venerupis (=Ruditapes) philippinarum）的自然种群数量急剧减少。为了弄清数量下降的原因，每月从山口采集蛤仔样本并进行组织学观察，在此过程中发现了三种原生动物寄生虫。透射电子显微镜显示，这些寄生虫分别是结缔组织中未鉴定的单孢子虫、消化腺中的马特廖虫属（Marteilia sp.）和卵母细胞中的类马特廖虫属（Marteilioides sp.）。组织病理学观察表明，马特廖虫属和类马特廖虫属对宿主无致病性。然而，感染单孢子虫可能会对蛤仔产生负面影响。这些寄生虫的感染率较低，应进一步开展研究以明确其分类地位并确定它们对蛤仔的致病性。
