Abstract：Objective To understand the pathogen spectrum of infectious diarrhea and track its molecular epidemic trend in Hunan Province, and to provide a scientific basis for comprehensive prevention and treatment of infectious diarrhea. Methods Through sentinel surveillance combined with outbreak monitoring system, infectious diarrhea samples in Hunan Province from 2015 to 2020 were collected, and bacterial pathogens were detected by bacterial culture and biochemical identification. The pathogen of the virus was identified by molecular biological methods, and some PCR positive samples were then sequenced. Results The total positive rate of samples from active monitoring of sentinel hospitals was 35.61%. The detection rate of virus was higher than that of bacteria (20.26% vs. 11.26%), and the detection rate of mixed pathogen infection was 4.09%. Salmonella infection was dominant in bacterial pathogens, and Salmonella typhimurium O∶4 was the main serotype. Rotavirus (group A) type G9P [8] and norovirus type GⅡ.4 Sydney [P31] infections were predominant in virus pathogens. The pathogen composition and genotypes of different monitoring varied greatly in different years. Norovirus outbreaks increased when the positive rate of bacteria was low but the positive rate of virus was high through sentinel hospital monitoring. Among infectious diarrhea outbreaks, 86.78% were norovirus infection, of which 69.43% were GⅡ infection, 12.42% G I infection, and 3.03% GⅡ and GⅠ mixed infections. Norovirus outbreaks showed significant seasonal variation, and the dominant genotype was GⅡ.2 [P16], accounting for 42.97%. Conclusion The proportion of virus in infectious diarrhea pathogens in Hunan Province from 2015 to 2020 was higher than that of bacteria. Salmonella typhimurium, rotavirus (group A) type G9P [8], and norovirus GⅡ.4 Sydney [P31] were the main pathogen and dominant serotype/genotype. GⅡ.2 [P16] was the dominant genotype of norovirus in outbreak surveillance. Through continuous sentinel surveillance data support, we make good preparations for outbreak prevention and control so as to contribute to a steady decline in the incidence rate of infectious diarrhea in Hunan Province.
2021, Vol. 28 
