Coliphages and Human Adenoviruses as Viral Indicators of Faecal Contamination in Water: A Critical Review of Environmental Occurrence, Detection Methods, and Public Health Risk with Implications for Food Safety in Nigeria

This review synthesises current knowledge on the role of viral indicators, specifically coliphages and human adenoviruses (HAdVs), for assessing faecal contamination in water. It aims to bridge environmental monitoring and food safety perspectives by evaluating the occurrence, detection, and public health implications of these viral contaminants across water matrices, with implications for food production systems. Traditional bacterial indicators do not accurately reflect the hazards associated with viral pathogens. While HAdVs have become reliable markers of faecal pollution due to their high environmental stability, global prevalence, and presence in sewage, coliphages show environmental stability comparable to enteric viruses and are becoming more widely recognised for source tracking. Probabilistic estimation of infection risks from aquatic viruses is now possible thanks to quantitative microbial risk assessment (QMRA) frameworks. There is a clear connection between water quality and food safety since polluted water sources, especially surface water utilised for irrigation and post-harvest processing, act as vital vectors for virus transmission to fresh produce and shellfish. Predicting public health threats accurately requires including viral markers in regular water quality monitoring. Standardising procedures and increasing environmental surveillance should be the top priorities in future initiatives to reduce viral exposures from food and water in Nigeria.