ABSTRACT
To analyze the population density, seasonal fluctuation of Aedes albopictus in Haizhu District, Guangzhou from 2017 to 2021, so as to provide a scientific basis for the monitoring and prevention and control of mosquito vector density of dengue fever. The data of dengue fever cases and Aedes surveillance data in Haizhu District, Guangzhou from 2017 to 2021 were collected, and the data of 2017-2019 and 2020-2021 were grouped to compare and analyze the characteristics of dengue epidemic and the density fluctuation of Aedes mosquitoes. A total of 517 dengue cases were reported in Haizhu District, Guangzhou from 2017 to 2021, of which only 7 cases were reported from 2020 to 2021, and the peak period of reported cases every year was August to November. Before the COVID-19 pandemic, there was a positive correlation between the number of local cases and the number of imported cases(rs=0.63, P<0.05) and BI(rs=0.73, P<0.05). The peak density of Aedes was from May to October, and the differences of mean BI(X~2=1 143.40,P<0.001), MOI(X~2=188.30,P<0.001), and SSI(X~2=4 499.43,P<0.001)before and after the COVID-19 pandemic were statistically significant. In general, before and after the COVID-19 pandemic, the density of Aedes in high-risk areas was higher than that in low-risk areas. After COVID-19 pandemic, the number of reported cases and the density of Aedes in Haizhu District decreased, but the density of Aedes in the high-risk area was still higher than that in low-risk areas, and a certain risk of outbreak still existed, so the government should continue to take more precise measures to strictly prevent dengue epidemic.
ABSTRACT
Analysis of a case of COVID-19 and dengue fever misdiagnosed key links, we provide basis for the development of COVID-19 prevention and control strategy in the epidemic period of dengue fever. We used descriptive epidemiological method to investigate and analyze the case, their close contacts and suspected sources of infection, tested SARS-CoV-2 by RT-PCR and dengue virus antigen and antibody by immunochromatography. The case had lived in Wuhan and Cambodia 14 days, and was diagnosed as suspected dengue fever in overseas hospital on January 23rd, 2020. On January 30, dengue antigen NS1 of the patient was tested suspiciously positive in an outpatient clinic in a "group hospital" in Cambodia, and negative for dengue antibodies IgM and IgG. The patient was diagnosed as "suspected dengue fever". In the early morning of January 31, the case entered Guangzhou and was quarantined in a hotel for observation. Blood samples were collected by medical staff at the hotel and sent to the Center for Disease Control and Prevention in Haizhu District for dengue fever detection by immunochromatography (colloidal gold). The results showed that the Dengue virus NS1 antigen was negative, IgM and IgG antibodies were negative, and "dengue fever" was excluded. On January 31, the hospital took a throat swab sample and the result was positive from SARS-CoV-2 nucleic acid test, which was reported as a "suspected COVID-19 case" on the network. On February 1, the Guangzhou Municipal Center for Disease Control and Prevention reviewed SARS-CoV-2 nucleic acid test and revised it as a "confirmed COVID-19 case". Some early symptoms of COVID-19 are similar with dengue fever. In the epidemic period of dengue fever, it is very important to make a good early diagnosis between dengue fever and COVID-19, early diagnosis and treatment is the key to prevent the spread of disease epidemic.