To evaluate the burden of nontyphoidal Salmonella infection in Guangzhou and provide information for strategies of foodborne diseases surveillance.MethodsBased on the active surveillance system established in nine hospitals from six districts, a 12-month population-based household survey in three districts, as well as national notifiable disease reporting system (NNDRS), attendance rates of patients with diarrhea, stool sampling rate, laboratory testing rate for Salmonella, sensitivity of testing method, and positive case reporting rate were calculated and adjusted by pyramid model ratio and uncertainty analysis to yield the burden ratio and make a comparison between active and passive surveillance. Then the local actual annual incidence of nontypoidal Salmonella infection was estimated and analyzed according to the foodborne diseases epidemiological burden pyramid model. ResultsThe average attendance rate of patients with diarrhea was 23.91%; stool sampling rate, laboratory testing rate for Salmonella, sensitivity of the stool culture method and positive case reporting rate of the active surveillance hospitals were 38.34%, 28.24%, 87.5% and 42.98% respectively, extrapolating rates of hospitals around the city as 38.34%, 28.24%, 47.5% and 20.94%. Accordingly, it was estimated that the actual annual incidence rate of nontyphoidal Salmonella infection was 508.5 cases (95%CI:347.5-802.5) per 100 000, with 64 586 (95%CI:44 136-101 921) as emerging cases, while the reported cases from NNDRS was only 171 and the annual incidence rate was 1.3 cases per 100 000. Among different age groups, the incidence of under 5 years was estimated as the highest (3 583.2 per 100 000), while age group from 15 to 24 years the lowest (23.5 per 100 000).ConclusionIt was the first time that the pyramid model was used on specific foodborne pathogen burden analysis in China, based on data from local surveys, indicating that active surveillance would help improve the stool sampling, laboratory test for Salmonella, sensitivity of the stool culture method, and positive case reporting, and the pyramid model would help gain effective and robust estimate of disease burden. According to the estimate, nontyphoidal Salmonella infection was a major public health problem in Guangzhou in terms of disease burden, which was higher than that of the U.S, with the highest incidence occurred in the age group younger than 5 years. The findings highlighted the necessity to carry out further investigations on risk factors and to implement effective intervention measures on Salmonella infection.