ABSTRACT
@#Objective To understand the epidemiological and etiological characteristics of influenza in Mianyang City from 2019 to 2021, so as to provide a basis for the prevention and control of influenza. Methods Influenza surveillance data in Mianyang City from 2019 to 2021 were collected and analyzed statistically. Results A total of 55 970 cases of influenza were reported in Mianyang City from 2019 to 2021, with an average annual incidence of 388.08/100 000. A total of 103 723 cases of influenza -like illness cases (ILI) were reported, with an average annual ILI% of 3.58%. The incidence, ILI% , and positive detection rates of influenza were all far higher than those in the corresponding period in 2019. The classification of the population is mainly composed of students under the age of 15. The top three reported cases were Fucheng District (20 118, 35.94%), Youxian District (6 394, 11.42%) and Jiangyou District (5 800, 10.36%). 10 126 samples of ILI were received and detected, with a positive rate of 19.53%, the positive rate of ILI samples was mainly students under 15 years old. The dominant strains of influenza viruses showed an alternating trend over the years, and A (H3) was the predominant type in 2019. Except for 2 A (H9) strains detected in 2021, the rest were all BV strains. Due to the impact of COVID-19 in 2020, the positive detection rate was low throughout the year. 43 outbreaks of ILI were reported, which were mainly occurred in winter, and most of them were in primary schools. Conclusion From 2019 to 2021, the characteristics of cases, ILI, pathogen surveillance and outbreak events of influenza in Mianyang City are basically the same, with students under 15 years of age and schools remaining the key population and sites of concern. the importance of non-pharmaceutical interventions for influenza prevention and control is further evidenced by the low incidence of influenza during the COVID-19 pandemic.
ABSTRACT
Background: Vector-borne diseases have become one of the most serious local public health threats. Monitoring and controlling vectors are important means of controlling vector-borne diseases. However, traditional vector surveillance systems in China mainly monitor vector density, making its early-warning effect on vector-borne diseases weak. In this study, we applied an integrated surveillance system of multiple arthropod vectors and reservoir host containing ecology, etiology, and drug resistance monitoring to obtain better knowledge on vector populations and provide early warning of suspicious vector-borne infectious disease occurrence. Methods: An ecology surveillance of mosquitoes, rodents, ticks, and chigger mites, a pathogen infection survey on mosquitoes and rodents, and a drug resistance survey on Aedes albopictus were conducted in 12 cities in Zhejiang Province in 2020. Results: A total of 15,645 adult mosquitoes were collected at a density of 19.8 mosquitoes per Centers for Disease Control and Prevention light trap. Culex tritaeniorhynchus (72.76%) was the most abundant species. The Breteau index of Ae. albopictus was 13.11. The rodent density was 0.91 rodents per hundred traps; the most abundant species was Rattus norvegicus (33.73%). The densities of dissociate and ectoparasitic ticks were 0.79 ticks per hundred meters and 0.97 ticks per animal, respectively. The most abundant tick species was Haemaphysalis longicornis (56.38%). The density of chigger mites was 14.11 per rodent; two species were identified, with the most abundant species being Walchia spp. mite (68.35%). No flavivirus or alphavirus was found in mosquito etiology monitoring, whereas the positivity rates of hantavirus, the pathogenic bacteria Leptospira spp., Orientia tsutsugamushi, and Bartonella spp. detected in rodent etiology monitoring were 1.86, 7.36, 0.35 and 7.05%, respectively. Field populations of Ae. albopictus in Zhejiang Province were widely resistant to pyrethroids but sensitive to most insecticides tested, including organophosphorus and carbamate insecticides. Conclusion: Integrated surveillance systems on multiple arthropod vectors (mosquitoes, ticks, mites) and animal reservoirs (rodents) can provide important information for the prevention and control of epidemic emergencies.
