Etiological, epidemiological, and clinical features of acute diarrhea in China

Abstract

National-based prospective surveillance of all-age patients with acute diarrhea was conducted in China between 2009‒2018. Here we report the etiological, epidemiological, and clinical features of the 152,792 eligible patients enrolled in this analysis. Rotavirus A and norovirus are the two leading viral pathogens detected in the patients, followed by adenovirus and astrovirus. Diarrheagenic Escherichia coli and nontyphoidal Salmonella are the two leading bacterial pathogens, followed by Shigella and Vibrio parahaemolyticus. Patients aged <5 years had higher overall positive rate of viral pathogens, while bacterial pathogens were more common in patients aged 18‒45 years. A joinpoint analysis revealed the age-specific positivity rate and how this varied for individual pathogens. Our findings fill crucial gaps of how the distributions of enteropathogens change across China in patients with diarrhea. This allows enhanced identification of the predominant diarrheal pathogen candidates for diagnosis in clinical practice and more targeted application of prevention and control measures.

Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1. A flowchart of the data collection and sorting procedures.

This flow diagram summarizes the number of patients with acute diarrhea for each analysis in this study.

Fig. 2. Pathogen spectrum and co-infection pattern of enteropathogens in diarrhea patients by age group in the mainland of China, 2009‒2018.

a The viral spectrum and co-infection pattern of 58,620 patients with acute diarrhea who had all the seven viral pathogens tested. b The bacterial spectrum and co-infection pattern of 59,384 patients with acute diarrhea who had all the 13 bacterial pathogens tested. c The parasitical spectrum and co-infection pattern of 11,167 patients with acute diarrhea who had all three parasitical pathogens tested. The proportion of each positive pathogen was noted in % and by the length of colored bars. The orange bar indicates viral mono-infection; the blue bar indicates bacterial mono-infection; the red bar indicates parasitical mono-infection; the green bar indicates co-infection. For viruses, co-infection means co-infection among viruses. For bacteria, co-infection means co-infection among bacteria. For parasites, co-infection means co-infection among parasites. DEC diarrheagenic Escherichia coli; NTS nontyphoidal Salmonella. Source data are provided as a Source Data file.

Fig. 3. Positive rate of pathogens by sex and age in patients with diarrhea in China, 2009‒2018.

a Viral pathogens. b Bacterial pathogens. c Parasite pathogens. The lengths of red bars indicate the positive rate of each pathogen. The lengths of blue bars and yellow bars indicate the positive rate of each pathogen by sex and age groups. The same group was marked by the same colors of bars filling. *Indicates a significant difference (chi-square test or Fisher’s exact test were two-sided and p < 0.05 was statistically significant) found within the group. DEC diarrheagenic Escherichia coli; NTS nontyphoidal Salmonella. Source data are provided as a Source Data file.

Fig. 4. The joinpoint regression of the positive rates of each enteropathogen by age of the patient.

a Viral pathogens. b Bacterial pathogens. A red point indicates the positive rate of patients in terms of age and the colored curves indicate fitted patterns by the red points. Legends give the annual percentage change (APC) value of each fitted curve for each enteropathogen. *Indicates that the APC is significantly different from zero at p < 0.05. A normal (Z) distribution was used to assess the significance of the APC. All statistical tests were two-sided and p < 0.05 was statistically significant. DEC diarrheagenic Escherichia coli; NTS nontyphoidal Salmonella. Source data are provided as a Source Data file.

Fig. 5. Spatial and temporal pattern of four clusters of enteropathogens in patients with diarrhea in the mainland of China during 2009‒2018.

Thirteen of the tested enteropathogens were formed into four clusters (a‒d). The seasonality was presented with a radar diagram based on the monthly positive rate from 2009 to 2018. The circumference is divided into 12 months in a clockwise direction, and the radius from inside to outside represents a particular year from 2009 to 2018. Seven ecological regions were marked (I, Northeast China district; II, North China district; III, Inner Mongolia-Xinjiang district; IV, Qinghai-Tibet district; V, Southwest China district; VI, Central China district; VII, South China district). Within each ecological region, the positive rate was noted and reflected by the background color. Histograms within each ecological region indicate the monthly positive rate averaged from 10-year data. The height of the bars indicates the positive rate of each month. *No sample in the month. The dendrogram in e, f display the clusters I‒IV. Green lines mean cluster I. Blue lines mean cluster II. Red lines mean cluster III. Yellow lines mean cluster IV. The incidence rate ratio, ranging from negative influence (blue) to positive influence (red). The features used for clustering are variables with statistically significant differences in the negative binomial model. DEC diarrheagenic Escherichia coli; NTS nontyphoidal Salmonella. Source data are provided as a Source Data file.