Some unusual features of mycobacteriosis in the cichlid fish Oreochromis mossambicus

• Published in: Journal of comparative pathology Vol. 102; no. 3; p. 335
• Main Authors: Noga, E J, Wright, J F, Pasarell, L
• Format: Journal Article
• Language: English
• Published: England 01-04-1990
• Subjects: Animals; Disease Outbreaks - veterinary; Fish Diseases - epidemiology; Fish Diseases - pathology; Fishes; Microscopy, Electron; Mycobacterium Infections - epidemiology; Mycobacterium Infections - pathology; Mycobacterium Infections - veterinary; Skin Diseases, Infectious - epidemiology; Skin Diseases, Infectious - pathology; Skin Diseases, Infectious - veterinary
• ISSN: 0021-9975
• DOI: 10.1016/S0021-9975(08)80022-9

Adult, aquarium-reared Oreochromis mossambicus (Tilapia mossambica), which were naturally infected with Mycobacterium marinum, displayed non-healing skin ulcers and other clinical signs considered to be typical of piscine mycobacteriosis. However, in addition, they frequently had melanotic foci in the skin and spleen, due to the presence of pigment cells surrounding the cutaneous and splenic inflammation. Such melanotic foci have never been reported in response to mycobacteriosis. All fish also have variable numbers of melanomacrophages which appeared to replace pancreatic acini. The relationship of the pancreatic melanomacrophages to the pathogenesis of mycobacteriosis is uncertain, but such lesions may have contributed to the chronic cachexia associated with this case.