Abstract:

Objective To analyze the epidemiological characteristics of dengue fever in Shenzhen area from 2013 to 2022 for evidences in prevention and control of this infection. Methods The data of dengue cases reported in Shenzhen area from 2013 to 2022 were retrieved from the China Disease Prevention and Control Information System. Descriptive epidemiology was used to analyze the characteristics of spatial, time and population distribution, infection places, the time from disease onset to definite diagnosis, outbreak status, and results of pathogen and mosquito vector monitoring. Results From 2013 to 2022, 1 388 dengue cases were reported in Shenzhen, the annual incidence was 4.45/100 000. Among them, there are 650 local cases, 533 foreign imported cases, and 205 imported cases domestically. The most reported cases were in 2014 (454 cases) and 2019 (523 cases), and the most reported months were from August to November (1 112 cases, 80.12%). The infection occurred in 10 administrative districts, accounting for 90.54% of the total community regions in the city. The median age at disease onset was 34 (27, 45) years, and the epidemic mainly occurred in population aged 20-59 years (1 238 cases, 89.19%). Male to female ratio was 1.80:1. The top three occupation was workers, housework and unemployed, business services (958 cases, 69.02%). The foreign imported cases were primarily from southeast Asian countries (528 cases, 99.06%), while the domestic imported cases were generally from Pearl River Delta areas (151 cases, 73.66%). The median interval from onset to diagnosis was 5 (3,7) days. Twenty local outbreaks were reported, ten outbreaks occurred in local construction sites, and 9 events occurred in October. Although multiple serotypes were prevalent, yet DENV-1 was predominant in both imported and local infections (83.31%, 597/713). The positive rate of serum dengue virus IgG antibody in healthy individuals was 1.98%, and there was no statistically significant difference in the positive rates among different years (χ²=3.01，P>0.05). The active period of Aedes albopictus was from May to November. Conclusion The epidemic situation of dengue fever in Shenzhen remains very serious, and the number of cases has been increasing compared with the previous ten years. The local infection was mainly caused by imported cases, which suggests that it is necessary to strengthen the monitoring and identify the imported cases so as to timely control the epidemic.

Key words: Dengue fever, Epidemiological characteristics, Serotype, Aedes albopictus, Shenzhen City