Investigation on Mycobacteriosis in aquarium fish: A periodic study in Ahvaz

Mycobacterial infection or Mycobacteriosis is one of the most important zoonotic bacterial diseases in fish, especially in aquarium fish, worldwide. Despite the importance of this disease, there is no record about the surveillance of this disease in Ahvaz region-Iran. In this investigation the occurrence of Mycobacterium spp. in ornamental fish was studied using PCR technique. In this survey, 150 fish were obtained from aquarium shops of Ahvaz. The fish was belonged to 5 species, i.e. Scatophagus argus, Astronotus ocellatus, Heross severus, Caesioteres sp. and Symphysodon aequifasciatus. The fish were transferred to the laboratory and examined after dissection. Meanwhile, liver, kidney and spleen samples were collected for PCR analysis. 80% of the examined fish showed no gross lesions at necropsy. However, only in a few fish some symptoms such as emaciation and anorexia were observed. In this study only 1 out of 150 fish (Heros severus) was detected as positive in PCR examination. Meanwhile, in DNA sequencing the bacterial species was recognized as Mycobacterium bovis. Other fish species showed no infection with Mycobacteria in PCR examination. Due to no pathogenesis of M. bovis in fish, this positive specimen can be considered as a transmission to fish from infected persons or feed products. These negative findings show that this Iranian region can be considered as a freeone for these particular pathogens.