Piscine gill epithelial cell necrosis due to Mycoplasma mobile strain 163 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 surface and kept at two different temperatures (20 and 25 degrees C). Gill tissues from experimentally infected tench and rainbow-trout gill tissue explants infected in vitro were compared by transmission electron microscopy, revealing that M. mobile was capable of producing gill epithelial 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. mobile 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 difference between the results at 20 and 25 degrees C.