Laboratory detection of imported dengue fever cases in Yuxi City, Yunnan Province, 2019
TIAN Jie1,2, FAN Zhi-hong3, YANG Juan4, JIANG Xue-ying3, YANG Ming-dong2, GUO Xiao-fang2
1. School of Public Health, Kunming Medical University, Kunming 650500, China; 2. Yunnan Provincial Key Laboratory of Vector-borne Infectious Diseases Control and Research, Yunnan Institute of Parasitic Diseases, Pu’er 665000, China;; 3. Department of Disinfection and Vector Control, Yuxi Center for Disease Control and Prevention, Yuxi 653100, China; 4. Department of Blood Transfusion, Yuxi People’s Hospital, Yuxi 653100, China;
Abstract：This study aimed to analyze the epidemiological characteristics and viral molecular genetic background of imported dengue cases in Yuxi City, Yunnan Province in 2019, to provide a scientific basis for the prevention and control of dengue fever. Serum samples from people with imported dengue cases were collected. The serotype of dengue virus was detected by real-time RT-PCR, and the envelope (E) protein gene was sequenced to perform phylogenetic analysis. A total of 23 imported dengue cases were monitored, comprising 18 cases from Jinghong City in Yunnan Province, 3 cases from Cambodia, and 2 cases from Myanmar and Vietnam. These cases were mainly distributed in Jiangchuan District (9 cases) and Hongta District (8 cases). Farmers (11 cases) and housekeepers and unemployed people (5 cases) were the main infected groups. A total of 20 samples were tested; 11 DENV-1, 5 DENV-2 and 1 DENV-3 were detected in 17 samples imported from Jinghong City. One DENV-1 was detected in 2 samples imported from Cambodia, and 1 sample imported from Myanmar was negative for DENV. Ten complete E gene sequences, comprising six DENV-1, three DENV-2 and one DENV-3, were obtained from the imported cases from Jinghong City. The six strains of DENV-1 had 100% nucleotide sequence identities to DENV-1 strains endemic in Jinghong City and imported from Cambodia in 2019, which belonged to genotype I. The three strains of DENV-2 had 99.8%~100% nucleotide sequence identity to DENV-2 strains endemic to Jinghong City in 2019, which belonged to the Asian I genotype and cosmopolitan genotype. The one DENV-3 strain had 99.3% nucleotide sequence identity to the strains endemic to Jinghong City in 2019, which belonged to genotype III. In conclusion, three serotypes of DENV from domestic and foreign countries were found to be imported to Yuxi City in 2019 and had the closest evolutionary relationship to the epidemic strains in Southeast Asia. In the future, the detection and monitoring of imported cases of dengue fever must be improved.
2021, Vol. 37 
