Prevalence and enumeration of general and host associated bacteriophages in selected surface water used for fishing and Bacteriurial confirmed urine in Uyo

Abstract

Bacteriophages are increasingly recognised as indicators of faecal contamination in aquatic environments, particularly in regions with limited wastewater management. This study investigated the presence and concentration of somatic coliphages in the Nwaniba River, a vital artisanal fishing site in southeastern Nigeria, and assessed the potential health risks to fishers and consumers. The aim was to quantify phage loads in surface water and urine samples and to estimate infection risks using a Quantitative Microbial Risk Assessment (QMRA) approach. Water samples from multiple points along the Nwaniba River and urine from bacteriuria-confirmed individuals engaged in fishing were analysed using plaque formation assays. Most water samples exhibited significant levels of phages, with sample 08 recording 6.32 Log PFU/mL and samples 07 and 10 reaching 8.08 and 11.08 Log PFU/mL, respectively. Urine cultures also revealed varying bacterial loads, with the highest concentrations found in samples linked to elevated phage levels in the water. QMRA modelling estimated that the daily infection risk through direct water contact could reach 86%, decreasing to 8.6% with appropriate cooking practices. Annual infection risk was projected to exceed 99.9% for uncooked exposure and approximately 98% under partial cooking scenarios. Sensitivity analysis identified key factors influencing risk, including phage persistence in fish and the volume of water
exposure during fishing activities. The findings confirm substantial bacteriophage contamination in the Nwaniba River and highlight the potential for microbial transmission through fish handling and consumption. These results underscore the need for improved water quality monitoring, public health education, and occupational safety interventions.