The role of cortisol as a physiological stress indicator in fish contamination by <i>Vibrio parahaemolyticus</i> and its implications for human health

Increased global consumption of fish and seafood, driven by their nutritional benefits, has highlighted concerns regarding bacterial contamination, particularly by Vibrio parahaemolyticus. This study investigates the prevalence and associated risk factors of V. parahaemolyticus in fish samples collected from three cities in the Kurdistan region of Iraq. A total of 185 fish samples were collected and analyzed for V. parahaemolyticus contamination using enrichment and isolation protocols. The overall detection rate was 9.19%, with no significant differences observed between cities, fish age, sex, or species. However, fish exhibiting abnormal physical signs, such as loose scales, pale gills, and bulging eyes, showed significantly higher contamination rates. Seasonal trends indicated a decreasing, though not statistically significant, trend in contamination from spring to summer. The cortisol level and lymphocyte count showed significant elevation, with a decrease in red cell count and abnormal physical appearance in fish compared with normal fish. These findings highlight the role of physiological and environmental factors in V. parahaemolyticus contamination and emphasize the need for improved biosafety measures in freshwater fish handling and processing to mitigate public health risks.