[Spatial autocorrelation of dengue cases and molecular biological characteristics of envelope gene of dengue virus in Guangzhou, 2019].

ABSTRACT

Objective: Analyze epidemiological situation of dengue fever,and survey impacts of four serotypes dengue viruses in Guangzhou, 2019. Methods: Information of patients was collected in Notifiable Infectious Disease Report System (NIDRS). Spatial autocorrelation of dengue cases was evaluated using ArcGIS version 10.2. Serum samples were tested by real-time PCR. Virus strains were isolated from positive sera. Then E gene was sequenced. Phylogenetic trees were including PhyMLsoftwarev 3.1. Results: A total of 1 655 dengue cases, consisted of 1 382 local cases and 273 imported cases, was confirmed in 2019. The incidence was 11.10 per 100 000 dengue cases were autocorrelated in Guangzhou. There were 18 high-high clusters. Most of the imported dengue cases were imported from Southeast Asian countries (86.08%,235/273) and African countries (2.56%,7/273). Of 749 serum samples detected by real-time PCR, the positive rate was 93.06% (697/749). Four hundred and sixty-four dengue virus strains had been isolated in 2019. Compared with data from the genotype tree of the former years, no genotype shift was discovered. Serotype 1 was still predominant. Serotype 2 was the significant strain in Baiyun district and Liwan district. Conclusions: Dengue fever was spreading all over Guangzhou in 2019. The suburban areas, which played a more critical role in causing the spread and outbreak of dengue fever, should be given more prominence. Inspection at ports should be enforced to prevent importing cases from African countries and Southeast Asian countries. The risk of serotype 2 cannot be overlooked. Four serotypes dengue viruses prevailed simultaneously in Guangzhou, which warns us to take precaution of severe dengue outbreaks.