Abstract:
Fish have crucial role in the human as well as household income generation. However, it could
harbor zoonotic bacterial pathogens. A cross- sectional study was conducted from November
2022 to November 2023 with the objectives of isolation and identification of Edwardsiella tarda
and Aeromonas hydrophila from Maya city lakes fish at Oromia Region, eastern Ethiopia. A total
of 270 fish tissue (heart, kidney and liver) samples from randomly selected 90 fish (Nile tilapia = 55
and African catfish =35) species were collected in addition to this 15 water samples were also
aseptically collected and bacteriologically examined and biochemical test is used to confirm isolation for
Edwerseilla tarda and Aeromonas hydrophila. An overall prevalence of 35.2% A. hydrophila and
23.8% E. tarda were observed. A. hydrophila showed significant difference between sample
sources (P= 0.03) but not among the Lakes. E. tarda was not significant both between sample
sources and among the Lakes (P> 0.05). Overall prevalence between A. hydrophila and E. tarda
as well as within a specific sample origin showed no significant difference (P>0.01). A.
hydrophila occurrence ranged from 23.5% to 41.7% and 30.0% to 36.4% in Nile tilapia and
Catfish, respectively, while E. tarda ranged from 23.1% to 50.0% and 9.1% to 14.3% in Nile
tilapia and Catfish, respectively. Among the fish species, E. tarda showed significant (p < 0.05)
association only in Lake Adelle. Tissue level prevalence of 8.1% for E. tarda and 10.7% for A.
hydrophila were observed at similar rate (P>0.05) Amongst the tissue, kidney and liver were
frequently infected (8.89% to 13.33%) for A. hydrophila and E. tarda compared to the heart with
proportions of 5.6% and 2.22%, respectively. The overall public health implication as fish and
water contamination by either of A. hydrophila and/or E. tarda was 54.3%, in that the lowest
(46.9%) was at Lake Tinke, while highest (71.4%) was from Adellxcxze Lake. The occurrence
of either A. hydrophila and/or E. tarda in kidneys and livers of the studied fish were significantly
higher (χ2=11.46; P =0.003) than in the heart. The results revealed high prevalence of E. tarda
and A. hydrophila in both water and fishes. The occurrence of A. hydrophila and E. tarda with
possible co-occurrence in the studied area has fish health and zoonotic implication requiring
interventions
