Epidemiological characteristics of typhoid and paratyphoid in provinces with high incidences and whole country, China,2015-2016

Objective To characterize the epidemiological trends of typhoid and paratyphoid in provinces with high incidences and in China,and provide evidence for the prevention and control of typhoid and paratyphoid. Methods Descriptive epidemiological analysis was conducted by using the incidence data of typhoid and paratyphoid reported through National Disease Surveillance Information Reporting System from 2015 to 2016. Results A total of 22 536 typhoid and paratyphoid cases,including 2 deaths,were reported in China during this period. The annual incidence rate was 0.83/100 000,which dropped by 18.63% compared with 2014. Among the reported cases,14 465 blood samples were collected,and 289 Salmonella spp. strains were isolated with an isolation rate of 2.00%. The clinical diagnosis ratio of typhoid to paratyphoid was 1.21:1. The majority of the cases were farmers and migrant workers,followed by young and school aged children. The incidence rates of typhoid and paratyphoid were highest in children aged 0-4 years(1.70/100 000 and 0.80/100 000). Guizhou,Yunnan, Guangxi,Guangdong,Zhejiang,Hunan and Xinjiang were the top seven provinces with high incidences of typhoid and paratyphoid. The case number in areas not covered by surveillance network increased. Conclusion At national level,the annual incidence rate of typhoid and paratyphoid declined. However the incidence rate in young people,especially in those aged <10 years,remained high. Salmonella typhi was the predominant pathogen. It is necessary to strengthen the surveillance in areas which are not covered by surveillance network.