loading . . . Changing Epidemiologic Characteristics of Dengue Fever in Chinese Mainland Between 2019 and 2024 <div xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="section"> <a class="named-anchor" id="d2471846e190"> <!-- named anchor --> </a> <h5 class="section-title" id="d2471846e191">Background:</h5> <p dir="auto" id="d2471846e193">Dengue fever is a mosquito-borne viral disease caused by the dengue virus, the prevalence of which has sharply increased in recent years worldwide. The indigenous dengue fever epidemic triggered by imported cases continues to pose a serious challenge to public health in China with a trend of expanding towards higher latitudes. The three largest local outbreaks of dengue fever in China since 2014 occurred in 2019, 2023, and 2024. A comparative analysis is needed to identify changes in the epidemiological characteristics of dengue fever during this period and to provide targeted prevention and control measures. </p> </div><div xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="section"> <a class="named-anchor" id="d2471846e195"> <!-- named anchor --> </a> <h5 class="section-title" id="d2471846e196">Methods:</h5> <p dir="auto" id="d2471846e198">A descriptive epidemiologic analysis method was performed to compare the basic characteristics of dengue fever between four phases (2019, 2020-2022, 2023, and 2024) with respect to geographic distribution, seasonality, imported sources, and composition of cases. The data on dengue fever cases were obtained from the Chinese Notifiable Reported Infectious Disease System (CNRIDS). The clinical criteria for diagnosing dengue fever were based on the guidebook published by National Health Commission of the People’s Republic of China. </p> </div><div xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="section"> <a class="named-anchor" id="d2471846e200"> <!-- named anchor --> </a> <h5 class="section-title" id="d2471846e201">Results:</h5> <p dir="auto" id="d2471846e203">Between 2019 and 2024 a total of 67,389 cases of dengue fever were reported in mainland China, including 8189 imported and 59,200 indigenous cases. In 2024, the reported cases of dengue fever covered 28 provincial-level administrative divisions (PLADs), 217 cities, and 895 counties with more involved areas than 2023 (28 PLADs, 195 cities, and 739 counties) but less than 2019 (29 PLADs, 246 cities, and 1269 counties). Dengue fever cases were located primarily on border areas of Yunnan (21,309 [36.0%]) and the Pearl River Delta region (15,829 [26.7%]). Most imported dengue cases (92.1% [7546/8189]) of imported cases originated from the Southeast Asian region. The rapid growth of indigenous cases (weekly reported cases > 500) in 2023 started 3 weeks earlier than 2019. In 2024 the local outbreak of dengue fever exhibited the earliest onset and had the longest duration (238 days [3 May-27 December]) compared to 218 days (25 May-29 December) in 2023 and 202 days (24 May-11 December) in 2019. Inter-provincial transmission of dengue fever rose progressively between 2019 and 2024, as follows: 2.4% (2019); 6.2% (2023); and 6.5% (2024). Notably, Yunnan accounted for 90.1% of total inter-provincial transmission of dengue fever in 2023, whereas Guangdong became the primary source in 2024 (96.4%). </p> </div><div xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="section"> <a class="named-anchor" id="d2471846e205"> <!-- named anchor --> </a> <h5 class="section-title" id="d2471846e206">Conclusions:</h5> <p dir="auto" id="d2471846e208">From 2019–2024 the geographic distribution of reported dengue fever cases has narrowed, primarily within the border areas of Yunnan and the Pearl River Delta. The onset of indigenous dengue fever transmission has occurred progressively earlier and the duration of sustained local dengue fever cases has been increasingly prolonged. The primary origin of reported dengue fever cases has shifted from Cambodia to Myanmar, then Indonesia and Laos. Since 2023, provinces other than Guangdong and Yunnan have faced dual pressures from inter-provincial transmission and the imported cases originating primarily from Indonesia, Thailand, and Laos. Control of dengue fever relies on close monitoring of international disease dynamics with enhanced surveillance of incoming travelers and mosquito vectors. </p> </div> https://www.scienceopen.com/hosted-document?doi=10.15212/ZOONOSES-2024-0069
