Molecular epidemiological and virological study of dengue virus infections in Guangzhou, China, during 2001–2010

Abstract

BackgroundDengue virus (DENV) infection is the most prevalent arthropod-borne viral infection in tropical and subtropical regions worldwide. Guangzhou has the ideal environment for DENV transmission and DENV epidemics have been reported in this region for more than 30 years.MethodsInformation for DENV infection cases in Guangzhou from 2001 to 2010 were collected and analyzed. The DENV strains were cultured and isolated from patients’ sera. Viral RNA was extracted from cell culture supernatants. cDNA was synthesized by reverse transcription PCR. Phylogenetic trees of four DENV serotypes were constructed respectively.ResultsIn total, 2478 DENV infection cases were reported; 2143 of these (86.43%) occurred during 3 months of the year: August, September and October. Of these, 2398 were local cases (96.77%) and 80 were imported cases (3.23%). Among the imported cases, 69 (86.25%) were from Southeast Asian countries. From the 90 isolated strains, 66.67%, 3.33%, 14.44%, and 15.56% belonged to DENV serotypes 1, 2, 3, and 4, respectively. DENV-1 was predominant in most of the years, including during 2 outbreaks in 2002 and 2006; however, none of the strains or genotypes identified in this study were found to be predominant. Interestingly, DENV strains from different years had different origins. Moreover, the strains from each year belonged to different serotypes and/or genotypes.ConclusionsSoutheast Asia countries were found to be the possible source of DENV in Guangzhou. These findings suggest that there is increasing diversity in DENV strains in Guangzhou, which could increase the risk of DENV outbreaks in the near future.

Isolation and characterization of dengue virus serotype 2 from the large dengue outbreak in Guangdong, China in 2014

“…The co-circulation of multiple DENV serotypes increased the risk of secondary infection, and a severe dengue case due to secondary infection emerged in Guangdong province in 2011 [31]. Five DENV-2 genotypes have been described: Asian I, Asian II, American/Asian, Cosmopolitan and American [7]. According to polygenetic analysis results, the new isolate GZ05/2014 belonged to the Cosmopolitan genotype, clustering with other DENV-2 isolates circulating in China in recent 10 years (Figure 3).…”

“…Guangdong province lies in southeastern China, characterized with humid subtropical climate, where the Aedes mosquitos are widely distributed and can breed throughout the year. Guangdong is the major affected area by DENV in mainland China, and sporadic epidemics caused by imported cases have been frequently reported in the past decades [7].…”

Functional properties of DENV EDIII-reactive antibodies in human DENV-1-infected sera and rabbit antiserum to EDIII

“…Thus far, only a chimeric recombinant DNA dengue vaccine developed by Sanofi Pasteur completed clinical trial phase 3, this vaccine can provide 60% protection to DENV-1, and 80-90% protection against DENV-3 and DENV-4, but no protection against DENV-2 (42). Based on the epidemiological and aetiological characteristics of dengue infection in southern China, DENV-1 is the most predominant serotype (accounting for >60% of all patients), DENV-2 is occasionally detected, and DENV-3 and DENV-4 are seldom observed (43)(44)(45)(46). Therefore, our research has been focused primarily on DENV-1 EDIII in human convalescent serum samples and DENV-1 EDIII immunized rabbit serum, in which the neutralization and ADE on heterotypic DENVs were also observed.…”

Epidemiological and etiological investigation of dengue fever in the Fujian province of China during 2004–2014

“…However, most infections are clustered in coastal provinces in southeast China, such as Guangdong, Guangxi, Fujian, Yunnan, and Hainan (Liu et al, 2014;Jiang et al, 2013). In the Fujian province, imported cases have been reported every year since 2004, and several local clustered epidemics occured in 2004, 2007, 2008(Yan et al, 2006Chen et al, 2015a, b).…”