摘要

<jats:p>During a general annual fish health survey in natural waters and ponds, epitheliocystis infections were recorded in fingerlings of two cyprinid fish species, the cultured common carp and the wild gibel carp. Benign and heavy infections were equally observed without mortality. In addition to the general health inspection of fish, histopathological examinations of infected gills and molecular biological investigations of separated epitheliocysts were performed. Epitheliocysts were formed both in the interlamellar epithelial cells and in the lamella-free multilayered epithelium of the gill filaments. At the early stage of infection darkstaining inclusion bodies densely stuffed with some pathogenic agents were located at the centre of the cell, while in a progressive stage of the process inclusion bodies within the host cells were disseminated in the cytoplasm and stained pale. Molecular studies demonstrated three different agents related to <jats:italic>Neochlamydia</jats:italic>, <jats:italic>Protochlamydia</jats:italic> and <jats:italic>Piscichlamydia</jats:italic> based on sequence analysis of short regions of the 16S rRNA gene. Among them, <jats:italic>Piscichlamydia</jats:italic> is a primary fish pathogen, while <jats:italic>Neochlamydia</jats:italic> and <jats:italic>Protochlamydia</jats:italic> mostly infect free-living amoebae but have adapted thoroughly to fish.</jats:p>

  • 出版日期2017-3