Abstract:
Objective To compare the epidemiological and molecular biological characteristics of envelope gene of imported and local dengue fever cases in Guangzhou, Guangdong, identify the factors influencing the dengue fever epidemic in Guangzhou, and provide evidence for the prevention and control of dengue fever.
Methods The incidence data of dengue fever in Guangzhou during this period were collected from National Notifiable Infectious Disease System. The demographic and epidemiological characteristics of the dengue fever cases were statistically analyzed using Excel 2010 and SPSS 20.0. Serum samples of the cases were detected by real-time polymerase chain reaction (PCR), the envelope gene of dengue virus was sequenced and analyzed to construct phylogenetic trees by using software MEGA 11.
Results A total of 4 245 dengue fever cases, including 534 imported cases and 3 711 local cases, were reported between 2015 and 2019. The incidence peak of imported cases occurred during June - October, just before the incidence peak of local cases during August - November. The imported cases were mainly distributed in Baiyun, Panyu and Yuexiu districts, while local cases were mainly distributed in Liwan, Baiyun and Haizhu districts, showing different area distribution. The real-time PCR indicated that dengue virus serotype 1 was predominant in Guangzhou during this period. The E gene sequencing showed close association among the strains from local cases, the strains from imported cases, circulating strains abroad and previous local strains.
Conclusion The incidence of dengue fever increased in Guangzhou during this period. Dengue fever was mainly caused by imported strains or by previous local strains. It is necessary to strengthen the multi-sectoral cooperation, improve supervision systems, conduct targeted health education and take control measures against imported and local cases to effectively control the spread of dengue fever.
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