ABSTRACT
ObjectiveThis study aimed to understand the epidemiological characteristics of hand-foot-mouth disease （HFMD） in Minhang District， Shanghai from 2009 to 2020， and provide a scientific basis for the prevention and control of HFMD. MethodsThe case information of HFMD was collected from the National Notifiable Infectious Diseases Reporting System of Chinese Center for Disease Control and Prevention. We used descriptive epidemiological methods to analyze the population characteristics， temporal and spatial distribution of HFMD， the pathogen composition of the case and its changing trend. ResultsFrom 2009 to 2020， a total of 66，198 cases of HFMD were reported in Minhang District， Shanghai， including 377 severe cases （severe case rate 0.57%） and 3 deaths （severs case fatality rate 0.80%）. There were more cases of HFMD in boys than in girls （1.5∶1）. HFMD patients aged under 5 years predominated， accounting for 88.91% of all cases. Majority of the cases （91.42%） were in scattered children （55.80%） and children in kindergartens （35.62%）. The incidence showed a cyclical trend， with low incidence years and high incidence years appearing alternately. The peak period was from April to July， and sometimes there were small peaks during October to December. A total of 12 years time-space scanning analysis revealed 3 clusters. The cluster centers were located in Wujing Town， Huacao Town and Xinzhuang Town， respectively. The proportion of EV71 in common cases was generally decreasing， and reduced to zero in 2019. The proportion of CoxA6 had increased year by year， and reached 75.00% in 2020. CoxA6 became the dominant pathogen in recent years. The number of severe cases had decreased year by year since 2010， and the dominant pathogen was EV71 （90.03% on average） in severe cases. ConclusionThe incidence of HFMD in Minhang District of Shanghai has a downward trend from 2014. The dominant pathogen changes from EV71 to CoxA6， and the dominant pathogen in severe cases is EV71. The discovered temporal and spatial clustering pattern is helpful for in-depth understanding of the distribution and epidemic trend of HFMD in Minhang District， and provides a scientific basis for epidemic prevention and control.
ABSTRACT
ObjectiveTo determine the epidemiological characteristics and risk factors of a norovirus GII.17 outbreak in Minhang District of Shanghai in 2018， and provide evidence for prevention and control measures of norovirus infection. MethodsDescriptive epidemiological analysis was performed. In addition， a retrospective cohort study was conducted to determine the risk factors. ResultsFrom May 30th to June 1st of 2018， a total of 132 cases （126 clinical cases and 6 confirmed cases） were documented，with an attack rate of 29.20%（132/452）.All cases were children in a kindergarten， with the average age of 5 years and 43.9% being male. The cases were reported in all the classes， with no clustering by class or floor．The epidemic curve was characterized by a point source exposure， which was estimated to be probably between 7 AM on May 30thand 0：30 AM on May 31st. The retrospective cohort study showed that the attack rate significantly differed between the children who had taken and did not take the school lunch （RR=∞） on May 30th，and those who had taken and did not take seafood noodles （RR=4.11， 95%CI：1.09-15.55） （P<0.05）. Among a total of 73 specimens， six specimens collected in child cases and one specimen in an asymptomatic chef tested positive for GII.17 type of norovirus. In addition， one retained food specimen of seafood noodles was positive for Aeromonas hydrophila. Viral shedding in the asymptomatic chef remained over 30 days. ConclusionThe outbreak was caused by seafood noodles contaminated by norovirus. It warrants enhancement in the regulation of food safety in canteens and regular examination of norovirus infection in catering industry employees.