Estimating the Risk of Acute Gastrointestinal Disease Attributed to E. coli O157:H7 in Irrigation Water and Agricultural Soil: A Quantitative Microbial Risk Assessment

Introduction: The occurrence of E. coli O157:H7 in the agricultural environment poses a serious threat to public health. The primary aim was to estimate the probability of illness caused by E. coli O157:H7 in irrigation water and agricultural soil niches. Methods: The Quantitative Microbial Risk Assessment was used and the risks were characterized using the Monte Carlo simulation with 10,000 iterations. Results: The mean levels of E. coli O157:H7 in the irrigation water and agricultural soil samples was 1.328 x 10(3) CFU/100 mL (Range: 0.00 to 13.000 x 10(3) CFU/100 mL) and 2.482 x 10(3) CFU/g (Range: 0.167 x 10(3) to 16.333 x 10(3) CFU/g), respectively. The risk of infection in humans exposed to this water and soil was 100%. In addition, a high risk of acute diarrheal disease was estimated at 25.0 x 10(-2) for humans exposed to contaminated water and/or soil. Summary: These results exceeded the WHO diarrheal disease risk standard of 1.0 x 10(-3). These findings demonstrated a high probability of acute gastrointestinal disease among humans exposed to E. coli O157:H7 in irrigation water and agricultural soil samples collected from the study sites representing a huge public health threat.