Epidemiological characteristics of typhus in China, 2017−2022

Objective To analyze the epidemic characteristics of typhus in China during 2017−2022 and provide scientific basis for the prevention and control strategy of typhus.

Methods The data of typhus surveillance cases in all provinces (autonomous regions and municipalities directly under the central government) from 2017 to 2022 were collected through the National Notifiable Infectious Disease Reporting Information System of Chinese Center for Disease Control and Prevention, and analyzed by descriptive epidemiological methods.

Results  From 2017 to 2022, the annual reported cases (incidence) in China were 929 (0.07/100 000), 971 (0.07/100 000), 1173 (0.08/100 000), 1069 (0.08/100,000), 1310 (0.09/100,000) and 1291(0.09/100 000), respectively , the number of reported cases and incidence showed a fluctuating increase trend. From 2017 to 2022, 22–24 provinces (309–342 counties and districts) have reported cases each year, and the annual reported cases were mainly distributed in Yunnan, Guangdong, Sichuan, Anhui, Hubei, Shandong, Guangxi, Hunan and Hebei. The proportion of reported cases in the total number of reported cases in the nine provinces fluctuated between 85.56% and 91.14%. The number of reported cases in Yunnan, Anhui and Hubei showed an increasing trend in general, while the number of reported cases in Shandong showed a decreasing trend. The total number of reported cases in the top 10 counties per year (proportion of the total number of cases in China) was 293 (31.53%), 284 (29.25%), 332 (28.30%), 400 (37.42%), 579 (44.20%) and 636 (49.26%), respectively, showing a trend of fluctuating increase. The occupational distribution was mainly farmers, students, scatteredchildren and preschool children, and the proportion of reported cases fluctuated between 61.04%–65.60%, 10.71%–15.43% and 7.67%–9.80%, respectively. The male to female sex ratio fluctuates between 0.86∶1 and 1.02∶1. The proportion of reported cases was the highest in the 40–64 age group (fluctuating between 38.54%–43.69%).

Conclusion From 2017 to 2022, Yunnan, Anhui, Guangdong, Guangxi, Sichuan, Hubei, Hunan, Hebei and Shandong provinces with the highest number of reported typhus cases each year accounted for more than 85.00% of the total number of reported cases in the country, and the annual reported cases in Yunnan, Hubei and Anhui show an increasing trend.The cases showed the characteristics of sporadic and local high incidence. It is necessary to strengthen real-time surveillance data analysis and risk assessment, timely early warning and response to the epidemic, and strengthen comprehensive prevention and control measures in key areas and key populations to further reduce infection risks.