Source attribution for sporadic nontyphoidal Salmonella cases using the frequency- matching Hald model

ObjectiveThis study aimed to provide scientific evidence for precise prevention measures by utilizing a frequency matching model to identify the primary food sources contributing to sporadic cases of nontyphoidal Salmonella （NTS） in a Chinese province from 2016 to 2020.MethodsData on NTS serotypes from both patients and food sources were collected and analyzed through the Foodborne Disease Surveillance Report System and the Food Contaminant Risk Surveillance System. Source attribution was determined using the Hald model， considering serotypes common to human cases and food sources.ResultsThe analysis revealed that livestock meat was responsible for 35.67% of NTS sporadic cases， with pork contributing significantly at 22.37%. Eggs and egg products accounted for 33.83% of NTS sporadic cases， while poultry and aquatic animals contributed 19.28% and 11.22%， respectively. According to the source attribution analysis， monophasic Salmonella typhimurium appeared to be the dominant serotype causing NTS cases in the province.ConclusionThis study concluded that pork plays a crucial role as an etiological food source for sporadic NTS cases in the province， as determined by the Hald model. These findings provide valuable insights into the prevention and control of NTS-related contamination. Moreover， the application of frequency matching models to address source attribution in sporadic cases can be extended to other provinces for similar investigations.