PISCINE GILL EPITHELIAL-CELL NECROSIS DUE TO MYCOPLASMA-MOBILE STRAIN163-K - COMPARISON OF IN-VIVO AND IN-VITRO INFECTION

This paper describes experiments with Mycoplasma mobile 163 K in tench inoculated via the gills, skin, peritoneal cavity or whole body surfa ce and kept at two different temperatures (20 and 25 degrees C). Gill tissues from experimentally infected tench and rainbow-trout gill tiss ue explants infected in vitro were compared by transmission electron m icroscopy, revealing that M. mobile was capable of producing gill epit helial cell necrosis in both, but that it was much more severe in the explants. M. mobile was found attached to chloride cells in the tench and between necrotic epithelial cells in the trout gill explants. M. m obile was recovered from the gills for up to 28 days after inoculation , from the skin and swim bladder for up to 14 days, and from the hind gut, kidneys and spleen for up to 8 days. There was no significant dif ference between the results at 20 and 25 degrees C.