Factors associated with the occurrence of human bacterial pathogens in Lake Victoria surface water and Nile tilapia (Oreochromis Niloticus) at Kasenyi trading and landing site in Uganda

Abstract

Background: Lake Victoria is the world’s second largest and the largest by surface area in Africa and Uganda. It had over five hundred fish species before the 1960’s but a decline has been experienced over the years to less than three hundred fish species altogether due to exotic species introductions, eutrophication, and ecosystem degradation. To try mitigating for aquatic ecosystems bacterial degradation; field and / or laboratory-based bacteriological monitoring of lake surface water quality has been attempted over the past years. As of 2008; pathogenic bacteria such as Escherichia coli, Salmonella species, and Vibrio species among others were being identified in lake water and by 2017; the same pathogenic bacterial groups were still a persistent problem in water. Methods: A cross-sectional field and laboratory-based survey involving the identification of the factors contributing to bacterial contamination of the Lake Victoria surface shore waters and the landed Nile Tilapia (Oreochromis niloticus) at Kasenyi Landing Site and the bacteriological analysis of the shore water samples and the Nile Tilapia (Oreochromis niloticus) was undertaken. Results: In Lake water; Citrobacter freundii was the most occurring human bacterial contaminant at 71% (22/31) while Klebsiella pneumoniae was the least occurring human bacterial contaminant at 6% (2/31). “Soil surface run-off” emerged as the most occurring factor related to possible bacterial contamination of the shore surface waters (72.7%; 8/11). The most occurring bacterial pathogen in Nile Tilapia was Enterococcus species at 77.5% (93/120). All vendors practiced hand washing and also had PPEs, however, 67% / 4/6 reported the lack of a disinfectant when at the stall. Conclusion: Citrobacter freundii had the highest occurrence in the Lake Victoria shore water while Enterococcus species had the highest occurrence in all the four Oreochromis niloticus organs (i.e. skin, intestine, gills, and muscle). Soil surface run-off emerged as the most possible occurring factor responsible for bacterial contamination of the shore surface waters. All the vendors were handling money when selling fish without first washing hands Recommendation: A larger sample size research to evidence the potential sources of human pathogenic bacteria into the Lake Victoria shore water and the fish at Kasenyi landing site. The Government should develop and implement a soil and water conservation and management plan. Put in place law enforcement mechanisms to ensure that the sanitation and personal hygiene guidelines