Outbreak of Aeromonas Hydrophila Affecting Fish Health in Babogaya Lake, Ethiopia

On October 6, 2023, reports emerged of a fish mortality outbreak in Babogaya Lake, in Bishoftu, in Ethiopia's Oromia Region. The Oromia Regional Government formally referred the occurrence to the National Animal Health Institute (AHI) in order to ascertain its cause. Samples from infected fish, lake water, and sediment were gathered for laboratory study as part of field research. <i>Aeromonas hydrophila</i> was detected in 5 (15.6%) of the 32 fish tissue samples that were analyzed. Selective culture, hemolysis tests on 7% sheep blood agar (β-hemolytic activity was seen in 5/32 samples, or 15.6%), biochemical assays, and PCR targeting the aerA gene were used to confirm the isolates. Identification was further validated by phenotypic profiling utilizing the Biolog GEN III system, which showed significant metabolic plasticity. Escherichia coli O157 and other pathogens were also recovered from two samples, indicating a more widespread problem of microbial pollution in the lake ecosystem. The extensive distribution of <i>A. hydrophila</i> and fecal indicator bacteria in various environmental sources points to deteriorating water quality and environmental stress as key causes of the outbreak. These results highlight the necessity of regular water quality monitoring, efficient waste management, and improved aquatic health surveillance in order to safeguard fish populations and public health in the Babogaya Lake area.