[Current infection status and epidemic risk analysis of Dengue fever and Chikungunya in Guangdong province, from 1990 to 2012].

OBJECTIVE: To understand the status of infection and epidemic trend of Dengue fever and Chikungunya in Guangdong.

METHODS: Retrospective survey and literature review were used to obtain data on the incidence, etiology of Dengue and Chikungunya. Serological survey was conducted to detect the specific-antibodies in healthy individuals for both Dengue virus(DENV)and Chikungunya virus (CHIKV).

RESULTS: Three epidemics of Dengue fever were observed during 1990-2012, with the annual incidence rates as 9.75/100 000 in 1995, 1.76/100 000 in 2002 and 1.25/100 000 in 2006, respectively. The predominant epidemic strains appeared to be DENV-2 and DENV-4 during 1990-1994. Since 1995,DENV-1 had become the predominant transmission strain which lasted for almost 13 years. Co-existence of multiple serotypes of DENV started in 2009. Of the 7 718 sera from healthy population during 2003-2012, 180 specimens were detected positive for specific DENV-IgG antibody, ended with a sero-prevalence rate of 2.33%. All 2 132 sera in 2012 were detected negative for CHIKV-IgG antibody.

CONCLUSION: The overall exposure level to Dengue was considered to be low in Guangdong province. However, the predominant transmission mode caused by DENV-1 had been gradually changed into the co-existence of multiple serotypes with the endemic signs appeared in some part of the areas. Chikungunya was a newly emerging disease in Guangdong since local people were lack of basic immunity barrier. Surveillance and control programs thus seemed important.