PATHOGENESIS OF AEROMONAS SPECIES IN STINGING CATFISH SHING (HETEROPNEUSTES FOSSILIS) OF BANGLADESH

The present experiment was conducted to evaluate the comparative ability of producing infections and causing mortality to inject Shing (Heteropneustes fossilis) with Aeromonas species. Nine Aeromonas isolates (A. hydrophila-3, A. sobria-3 and A. salmonicida-3) were injected to 9 different groups (each group consisting of 10 fish) of healthy Shing. Experimental Shing (H. fossilis) were injected with A. hydrophila, A. sobria and A. salmonicida to groups 1-3, 4-6 and 7-9, respectively while group 10 was injected with sterile phosphate buffered saline (PBS) and served as the control. For pathogenicity test, dose of 6.7 × 10 6 cfu/fish with each bacterial species were injected intramuscularly and monitored upto two weeks. The highest clinical infections were developed 100% in group 3 whereas only 30% in group 9. At the end of the experiment (after two weeks), the cumulative mortality rate was also recorded highest (90%) in group 3 and lowest (30%) in group 9. However, the development of infection and mortality to the injected Shing fish was associated more severely by Aeromonas hydrophila than A. sobria and A. salmonicida, used in this experiment.