Etiological surveillance for diarrhea in Shanghai from August 2013 to July 2014

Abstract

To understand the pathogen spectrum and epidemiological characteristics of diarrhea cases in Shanghai from August 2013 to July 2014. The survey was conducted in 23 hospitals at different levels randomly selected in Shanghai, the diarrhea cases seeking medical care in these hospitals were sampled, and stool samples were collected from them for pathogen isolation. Among 3 467 stool samples detected, 1 561 were positive for at least 1 pathogen (45.02%). A total of 6 kinds of bacteria and 5 kinds of viruses were detected. The positive rate for bacterium was 13.46%, mainly Vibrio parahaemolyticus (172 cases) and Salmonella (143 cases). The positive rate for virus was 27.75%, mainly Norovirus (471 cases) and Rotavirus (312 cases). The positive rates peaked obviously in summer and during autumn-winter. The positive rate of virus was higher than that of bacterium during autumn-winter, and the positive rate of bacterium was higher than that of virus in summer, the differences were statistically significant (P<0.05). Stratified analysis showed the constituent ratio of virus positive samples during November-February was highest among all age groups, however, the difference was not statistically significant (P>0.05). The constituent ratio of bacterium positive samples during June-September was highest in all age groups, the difference was statistically significant (P<0.05). The proportion of the cases with fever in bacterium positive group (19.06%) was higher than those in virus positive group (10.91%), the difference had statistically significance (P<0.05). The pathogen spectrum of diarrhea was relatively wide in Shanghai and the seasonality of the incidence was obvious. Specific etiological surveillance and control strategies should be strengthened among risk groups in different seasons.