Background: Hand, foot and mouth disease (HFMD) has circulated in China and caused yearly outbreak. To understand the transmission of the disease and to assess the spatial variation in cases reported, we examined age-specific transmission characteristics and reporting rates of HFMD for 31 provinces in mainland China. Methods: We first analyzed incidence spatial patterns and age-specific incidence patterns using dataset from 2008 to 2012. Transmission characteristics were estimated based on catalytic model. Reporting rates were estimated using a simple mass action model from "Time Series Susceptible Infectious Recovered" (TSIR) modeling.
The incidence of hemorrhagic fever with renal syndrome (HFRS) in Qingdao, China was three times higher than that of the average national level. Here we characterized the epidemiology, ecological determinants and pathogen evolution of HFRS in Qingdao during 2007–2015. In this longitudinal study, a total of 1846 HFRS patients and 41 HFRS-related deaths were reported. HFRS in Qingdao peaked once a year in the fourth quarter. We built a time series generalized additive model, and found that meteorological factors in the previous quarter could accurately predict HFRS occurrence. To explore how meteorological factors influenced the epidemic of HFRS, we analyzed the relationship between meteorological factors and hantavirus-carrying states of the hosts (including rodents and shrews). Comprehensive analysis showed humidity was correlated to high host densities in the third quarter and high hantavirus-carrying rates of animal hosts in the third to fourth quarters, which might contribute to HFRS peak in the fourth quarter. We further compared the L segments of hantaviruses from HFRS patients, animal hosts and ectoparasites. Phylogenetic analysis showed that hantaviruses in gamasid and trombiculid mites were the same as those from the hosts. This indicated mites also contributed to the transmission of hantavirus. Furthermore, Hantaan virus from HFRS patients, hosts and mites in Qingdao formed a distinct phylogenetic cluster. A new clade of Seoul virus was also identified in the hosts. Overall, meteorological factors increase HFRS incidence possibly via facilitating hosts’ reproduction and consequent mite-mediated hantavirus transmission. New hantavirus subtypes evolved in Qingdao represent new challenges of fighting against HFRS.
Summary
Tracing and isolation of close contacts is used to control outbreaks of coronavirus disease 2019 (COVID‐19) in China. However, risk factors associated with occurrence of COVID‐19 among close contacts have not been well described. 106 household contacts were included in this study, of whom 19 were developed into COVID‐19 cases and the secondary attack rate was 17.9%. Multivariable analysis showed increasing risk of occurrence of COVID‐19 among household contacts associated with female of index patients (Adjusted Hazard Ratio [aHR] = 3.84, 95%CI = 1.07‐13.78), critical disease of index patients ([aHR] = 7.58, 95%CI = 1.66‐34.66), effective contact duration with index patients >2 days ([aHR] = 4.21, 95%CI = 1.29‐13.73), and effective contact duration >11 days ([aHR] = 17.88, 95%CI = 3.26‐98.01).The sex and disease severity of index COVID‐19 patients, and longer effective contact duration with COVID‐19 confirmed cases could help epidemiologists to identify potential COVID‐19 case among household contacts at an early stage.
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