[Analysis of reported infectious diarrhea (other than cholera, dysentery, typhoid and paratyphoid) in China in 2011].

OBJECTIVE: To analysis the etiological and epidemiological characteristics of the reported infectious diarrhea (other than cholera, dysentery, typhoid and paratyphoid) cases in China in 2011.
METHODS: A total of 836 591 reported infectious diarrhea cases were collected from "China Information System for Disease Prevention and Control" since first week to fifty-second weeks in 2011, 59 929 out of which were laboratory-confirmed. The information of thirty public health emergencies relevant with infectious diarrhea was collected from "Emergency Public Reporting System" between first week and fifty-second weeks in 2011. The epidemiological characteristics of reported cases, confirmed cases and outbreaks, and the pathogenic spectrum of confirmed cases were then analyzed.
RESULTS: In 2011, 836 591 infectious diarrhea cases (other than cholera, dysentery, typhoid and paratyphoid) were reported, and the incidence rate was 62.39/100 000. More than half patients were children aged under 5 year-old, accounting for 52.13% (436 098/836 591) and the incidence rate was 447.06/100 000 (436 098 cases). Most of the ill children were scattered, accounting for 50.53% (422 752/836 591). Reported cases showed two incidence peaks, with a summer peak from twenty-third weeks to thirty-fifth weeks, accounting for 34.33% (287 231/836 591) and a winter peak from forty-third weeks to fifty-second weeks, accounting for 23.54% (196 939/836 591). Cases distributed all over China, the incidence in Beijing (253.00/100 000 (49 619 cases)), Tianjin (244.34/100 000 (31 614 cases)), Zhejiang (204.42/100 000 (111 257 cases)), Ningxia (132.16/100 000 (9328 cases)) and Guangdong (127.40/100 000 (132 880 cases)) ranked the top five. Among the 30 public health emergencies, 5 outbreaks had lab tested pathogenic results, including 4 were norovirus-induced. Laboratory-confirmed cases accounted for 7.16% (59 929/836 591) of the case reported, including 56 687 viral cases and 3242 bacterial cases. Rotavirus cases took the highest proportion of viral cases, at 97.35% (53 612/55 185); and 97.15% (53 612/55 185) of which were children aged under 5 year-old. 82.42% (45 480/55 185) of the cases distributed in Guangdong and Zhejiang province, with the incidence peak from fiftieth weeks to fifty-first weeks, accounting for 15.42% (8508/55 185) of the whole year cases. The main pathogens of bacterial diarrhea were Salmonella, Vibrio parahaemolyticus and Escherichia coli, accounting for 48.43% (1570/3242), 32.20% (1044/3242) and 8.57% (278/3242) respectively, with the incidence peak from thirty-first weeks to thirty-fifth weeks, accounting for 23.01% (746/3242). Salmonella infection patients were mainly from Shanghai, Guangdong and Zhejiang province (91.59% (1438/1570)), Vibrio parahaemolyticus patients were mainly from Shanghai (80.94% (845/1044)), and Escherichia coli patients were mainly from Guangdong province (84.17% (234/278)). Salmonella patients were concentrated in 0-9 years group, accounting for 42.36% (665/1570), while Vibrio parahaemolyticus patients in 20-39 years group, accounting for 81.99% (856/1044), and Escherichia coli patients in under 1 year old and 20-39 years group, accounting for 63.67% (177/278).
CONCLUSION: In China, children aged under 5 year-old should be the priority population in surveillance of infectious diarrhea. Rotavirus is the main pathogen causing infectious diarrhea. The lab-testing and case-reporting capabilities differed greatly among areas.