Research Article: Epidemiological and clinical characteristics of Dengue virus outbreaks in two regions of China, 2014 – 2015

Date Published: March 5, 2019

Publisher: Public Library of Science

Author(s): Jiaqi Cao, Hong Deng, Lei Ye, Xuezheng Ma, Shuru Chen, Xiaohong Sun, Xuemin Wu, Tao Yan, Liping Zhang, Lijuan Liu, Lili Li, Wuping Li, Kongxin Hu, Giovanna Barba-Spaeth.


Dengue virus (DENV), a single-stranded RNA virus and Flaviviridae family member, is transmitted by Aedes aegypti and Aedes albopictus mosquitoes. DENV causes dengue fever, which may progress to severe dengue. Hospital-based surveillance was performed in two Chinese regions, Guangzhou and Xishuangbanna, during the dengue epidemics in 2014 and 2015, respectively. Acute-phase serum was obtained from 133 patients with suspected dengue infections during the peak season for dengue cases. Viremia levels, virus sero-positivity, serotype distribution, infection type, clinical manifestations and virus phylogenetics were investigated. Of the 112 DENV-confirmed cases, 92(82.14%) were IgM antibody-positive for DENV, and 69(51.88%) were positive for DENV RNA. From these cases, 47(41.96%) were classified as primary infections, 39(34.82%) as secondary infections and 26 (23.21%) as undetermined infections. The viremia levels were negatively correlated with IgM presence, but had no relationship with the infection type. DENV-1 genotype V dominated in Guangzhou, whereas the DENV-2 Cosmopolitan genotype dominated in Xishuangbanna, where fewer DENV-1 genotype I cases occurred. DENV-2 is associated with severe dengue illness with more serious clinical issues. The strains isolated during 2014–2015 are closely related to the isolates obtained from other Chinese regions and to those isolated recently in Southeast Asian countries. Our results indicate that DENV is no longer an imported virus and is now endemic in China. An extensive seroepidemiological study of DENV and the implementation of vector control measures against it are now warranted in China.

Partial Text

Dengue virus (DENV), a Flavivirus genus member of the Flaviviridae family, is transmitted by Aedes aegypti and Aedes albopictus mosquitoes. The virus is endemic in many tropical and subtropical countries where it is associated with outbreaks of dengue disease. Globally, approximately 390 million people are estimated to be infected with DENV each year, and disease manifestations occur in around 96 million people [1]. The clinical signs and symptoms of DENV infections can manifest themselves as mild fever, hemorrhagic fever, or fatal shock syndrome, or infections can be asymptomatic [2,3]. Dengue, the second most important vector-borne disease compared with malaria. Currently, the CYD-TDV vaccine (dengvaxia) is licensed since 2015 in 20 countries with low efficacy and increased risk of severe disease among naïve individuals [4,5,6,7,8,9], but there are no specific therapeutics available for it, and substantial vector control efforts have not prevented its rapid re-emergence and global spread, a situation that poses a great threat to human health.

Dengue fever is an acute, emerging infectious disease caused by DENV, which is transmitted by Aedes aegypti and Aedes albopictus mosquitoes causing around 50–100 million disease cases every year, and with its associated high morbidity and mortality, especially in developing countries, poses a great threat to public health worldwide [31]. The case fatality rate for untreated dengue patients was around 20%, but with early diagnosis, better clinical management and improved fluid replacement it has fallen to less than 1% [32]. Over the last four decades, three large dengue outbreaks resulting in around 0.7 million cases and 600 deaths occurred in Foshan (mainland China) in 1978 and in Hainan Province in 1980 and 1986 [27]. These epidemics were characterized by their sudden onset and rapid transmission. Since the 1990s, dengue epidemics have spread gradually from the south-eastern coastal regions to the northern and western regions of China and have become endemic in the south-eastern coastal regions and sporadic in the inner land.