Epidemiological characteristics of severe fever with thrombocytopenia syndrome in Hefei of Anhui Province: a population-based surveillance study from 2011 to 2018.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne disease caused by the SFTS virus (SFTSV) of family Phenuiviridae. Since the virus was first identified in 2009, it has been rapidly spread in many Asian countries including Myanmar, Korea, Japan, and central China. In this study, we investigated the epidemiological characteristics of SFTS patients in Hefei from 2011 to 2018. In addition, we conducted a serological survey of SFTSV-specific antibody among healthy residents of five counties. We performed a retrospective observational study of SFTS cases reported to Hefei Center for Disease Control and Prevention (CDC) during Jan 2011 to Dec 2018. Almost every patient completed a structure questionnaire including clinical examination, course of disease, and history of epidemiology. A total of 754 serum specimens were collected and tested for IgG antibody with double-antigen sandwich ELISA method. Of 257 cases reported during that period, 33 died, with a case fatality rate of 13.0%. We found no significant difference between 30 non-survivors and 198 survivors except for age. The overall rate of seropositivity for SFTSV antibodies among healthy residents were 20.16%. We demonstrated that living in hilly areas, direct contact with domestic livestock and knowledge of tick-borne disease were significantly associated with positive serology result. SFTSV infection was prevalent among farming-related populations. Our study identified a relatively high seroprevalence of SFTSV-specific antibody in healthy residents, which provided the basis for asymptomatic SFTSV infections. More attention should be given to susceptible population and prevent SFTSV outbreak in high-endemic areas.

Impact of temperature variation between adjacent days on childhood hand, foot and mouth disease during April and July in urban and rural Hefei, China.

Previous studies have found that both high temperature and low temperature increase the risk of childhood hand, foot and mouth disease (HFMD). However, little is known about whether temperature variation between neighboring days has any effects on childhood HFMD. A Poisson generalized linear regression model, combined with a distributed lag non-linear model, was applied to examine the relationship between temperature change and childhood HFMD in Hefei, China, from 1st January 2010 to 31st December 2012. Temperature change was defined as the difference of current day's mean temperature and previous day's mean temperature. Late spring and early summer (April-July) were chosen as the main study period due to it having the highest childhood HFMD incidence. There was a statistical association between temperature change between neighboring days and childhood HFMD. The effects of temperature change on childhood HFMD increased below a temperature change of 0 °C (temperature drop). The temperature change has the greatest adverse effect on childhood HFMD at 7 days lag, with 4 % (95 % confidence interval 2-7 %) increase per 3 °C drop of temperature. Male children and urban children appeared to be more vulnerable to the effects of temperature change. Temperature change between adjacent days might be an alternative temperature indictor for exploring the temperature-HFMD relationship.

Highly Prevalent SARS-CoV-2 Antigenemia in COVID-19 Patients.

Background: Many issues, such as severity assessment and antibody responses, remain to be answered eagerly for evaluation and understanding of COVID-19. Immune lesion is one of key pathogenesis of the disease. It would be helpful to understand the disease if an investigation on antigenemia and association was conducted in the patients with SARS-CoV-2 infection. Methods: A total of 156 patients admitted to the First People's Hospital of Hefei or Anhui Provincial Hospital on January to February 2020 were involved in this study. SARS-CoV-2 nucleocapsid (NP) antigen, specific IgM/IgG antibodies, and RNA were detected in sequential sera from three COVID-19 patients, and additional 153 COVID-19 patients by means of NP-antigen capture enzyme-linked immunosorbent assay, colloidal gold quick diagnosis, and real-time RT-PCR, respectively. The clinical types of COVID-19 patients were classified into asymptomatic, mild, moderate, severe, and critical, following on the Chinese guideline of COVID-19 diagnosis and treatment. The demographic and clinical data of patients were obtained for comparable analysis. Results: NP antigen was detected in 5 of 20 sequential sera collected from three COVID-19 patients with typically clinical symptoms, and 60.13% (92/153) expanded samples collected within 17 days after illness onset. No SARS-CoV-2 RNA segment was detected in these sera. The NP positive proportion reached a peak (84.85%, 28/33) on 6 to 8 days after illness onset. Both NP concentration and positive proportion were increased with the increase of clinical severity of COVID-19. Compared to NP negative patients, NP positive patients had older age [years, medians (interquartile ranges (IQR)), 49 (6) vs. 31 (11)], lower positive proportion of NP specific IgM [27.17% (25/92) vs. 59.02% (36/61)], and IgG [21.74% (20/92) vs. 59.02% (36/61)] antibodies, and longer duration [days, medians (IQR), 24 (10) vs. 21 (13)] from illness to recovery. Conclusions: SARS-CoV-2 NP antigenemia occurred in COVID-19, and presented highly prevalent at early stage of the disease. The antigenemia was related to clinical severity of the disease, and may be responsible for the delay of detectable SARS-Cov-2 IgM.

Cloning, characterization and expression of two new polyphenol oxidase cDNAs from Agaricus bisporus.

Two new polyphenol oxidase (PPO) cDNAs (PPO3 and PPO4 cDNAs, accession numbers GQ354801 and GQ354802, respectively) were obtained by RACE-PCR from Agaricus bisporus. PPO3 cDNA was 1844 bp in length with an open reading frame of 1731 bp, while PPO4 cDNA was 2042 bp with an open reading frame of 1836 bp. PPO3 and PPO4 cDNAs, with 52% identity at the nucleic acid level, encoded a 576-amino acid protein of 66.3 kDa and 611-amino acid protein of 68.3 kDa, respectively. Mature forms of PPO3 and PPO4 were characterized after removing the specific C-terminal region and expressed in Escherichia coli BL21 (DE3) RIPL using pGEX-4T-1 vector. The expressed proteins were probed by the anti-A. bisporus PPO antibody but without PPO activity. This indicated that the recombinant mature PPO3 and mature PPO4 could not form an active center in prokaryotic expression system.

Short-term effects of extreme meteorological factors on childhood hand, foot, and mouth disease reinfection in Hefei, China: A distributed lag non-linear analysis.

BACKGROUND: Hand, foot, and mouth disease (HFMD) is a major public health issue in China with a high burden of reinfection. Previous studies presented evidence of the relationship between meteorological factors and HFMD incidence, but no study examined the effects of extreme meteorological factors on HFMD reinfection. METHODS: Daily HFMD reinfection counts and meteorological data of Hefei city were collected from 2011 to 2016. A distributed lag non-linear model was used to quantify the effects of extreme weather (wind speed, sunshine duration, and precipitation) on HFMD reinfection. All effects were presented as relative risk (RR), with 90th or 10th percentiles of meteorological variables compare with their median values. Confounding factors, such as mean temperature, relative humidity, day of week, and long-term trend were controlled. RESULTS: A total of 4873 HFMD reinfection cases aged 0-11 years were reported. Extremely high precipitation, low wind speed, and low sunshine duration increased HFMD reinfection risk. The effect of extremely high precipitation was greatest at 8 days lag (RR = 1.01, 95%CI: 1.00-1.02). Extremely low wind speed and low sunshine increased 19% (RR = 1.19, 95%CI: 1.09-1.32) and 12% (RR = 1.12, 95%CI: 1.00-1.26) risk at lag 0-12 days, respectively. By contrast, extremely high wind speed and high sunshine duration exerted certain protective effects on HFMD reinfection at lag 0-12 days (RR = 0.76, 95%CI: 0.66-0.88; RR = 0.88, 95%CI: 0.79-0.99, respectively). Subgroup analyses showed that nursery children were the most sensitive people to the extreme wind speed and sunshine duration. Children aged 4-11 years appeared to be more susceptible to extreme sunshine duration than children aged <3 years. CONCLUSION: The present study provides evidence that extreme meteorological factors exert delayed effects on HFMD reinfection. Developing an early warning system is necessary for the protection of children from harm due to extreme meteorological factors.

A hospital cluster combined with a family cluster of avian influenza H7N9 infection in Anhui Province, China.

OBJECTIVES: To identify human-to-human transmission of H7N9 avian influenza virus, we investigated a hospital cluster combined with family cluster in this study. METHODS: We obtained and analyzed clinical, epidemiological and virological data from the three patients. RT-PCR, viral culture and sequencing were conducted for determination of causative pathogen. RESULTS: The index case presented developed pneumonia with fever after exposure to chicken in a poultry farm. Case A presented pneumonia with high fever on day 3 after she shared a hospital room with the index case. Case B, the father of the index case, presented pneumonia with high fever on day 15 after he took care of the index case. H7N9 virus circulated in the local farm to which the index case was exposed. Full genomic sequence of virus showed 99.8-100% identity shared between the index case and case A or case B. Compared to the earliest virus of Anhui, a total of 29 amino acid variation sites were observed in the 8 segments. CONCLUSIONS: A hospital cluster combined with family cluster of H7N9 avian influenza infection was identified. Air transmission resulted in the hospital cluster possibly. A poultry farm was the initially infectious source of the cluster.

Short-term exposure to sulfur dioxide and the risk of childhood hand, foot, and mouth disease during different seasons in Hefei, China.

BACKGROUND: Sulfur dioxide (SO2) is an important component of air pollution, adversely impacting human health worldwide. This study aimed to examine the association between short-term exposure to SO2 and childhood hand, foot, and mouth disease (HFMD) in Hefei, China. METHODS: A Poisson generalized additive model (GAM) combining the time-series regression analyses was used to fit the SO2-HFMD association. The effect of SO2 was estimated using the single-day lag models (lag0, lag1, lag2) and the moving average lag models (lag01, lag02) We also conducted stratified analyses by season, ages (0-4 years old, 5-14 years old), gender (male, female), childcare patterns (scattered children, kindergarten children) and residence areas (urban, rural). Two-pollutant models were adopted to test the robustness of the results. RESULTS: There was a statistically significant association between SO2 and the risk of childhood HFMD. For total cases, the relative risk (RR) at lag0 was 1.038 (95% confidence interval (CI): 1.018-1.057) in whole-period and 1.088 (95% CI: 1.059-1.118) in cold season. During cold season, we observed significant associations between SO2 and HFMD among all subgroups except for children aged 5-14 years old and the adverse effects occurred on lag0, lag1, lag01, lag02. However, in hot season, SO2 were significant only for females (lag01 with RR = 1.054; 95%CI = 1.007-1.101) and scattered children (lag01 with RR = 1.054; 95%CI = 1.007-1.101). In general, females and scattered children appeared to be more vulnerable to SO2. CONCLUSIONS: This study suggests a significant association between SO2 and HFMD. especially during cold season. Compared with males and kindergarten children, females and scattered children are at higher risk of developing HFMD.

Effects of relative humidity on childhood hand, foot, and mouth disease reinfection in Hefei, China.

BACKGROUND: In recent years, hand, foot, and mouth disease (HFMD) has become a major public health issue in China, and its reinfection rate has been high. Numerous studies have examined the effects of meteorological factors involved in HFMD infection. However, no study has investigated the effects on HFMD reinfection. The present study analyzed the relationship between relative humidity and HFMD reinfection. METHODS: We employed a distributed lag nonlinear model to evaluate the relationship between relative humidity and childhood HFMD reinfection in Hefei, China during 2011-2016. This model controlled confounding factors, including seasonality, long-term trend, day of the week, precipitation, and mean temperature. RESULTS: Childhood HFMD reinfection cases occurred mainly from April to July, and the second peak occurred from October to December. A statistically significant association was observed between relative humidity and HFMD reinfection with delayed effects. The adverse effect of high relative humidity (>75%) appeared later than those of low relative humidity (<75%). Moreover, the highest relative risk (RR 1.08, 95% CI 1.04-1.13) occurred when the relative humidity was 100% and had an 8-day lag. Given the differences between gender and age groups, the effects of extremely high relative humidity on females and those aged ≥4years were higher than those of other groups and caused the highest cumulative relative risks at lag 0-9 or 0-10days (Female: RR 2.00, 95% CI 1.23-3.26; Male: RR 1.55, 95% CI 1.04-2.30; Aged ≥4years: RR 2.31, 95% CI 1.27-4.18; Aged <4years: RR 1.51, 95% CI 1.04-2.20). CONCLUSION: High and low relative humidity were found to cause the elevated risks of HFMD reinfection, and the highest risk was observed at extremely high relative humidity. Early warning systems should be built for the protection of susceptible populations, particularly females and children aged ≥4years.

Nonlinear and Interactive Effects of Temperature and Humidity on Childhood Hand, Foot and Mouth Disease in Hefei, China.

BACKGROUND: Hand, foot and mouth disease (HFMD) is one of the major infectious diseases among children and remains a health threat, especially among Asian countries. Many epidemiologic studies suggested significant association of air temperature and humidity with childhood HFMD; however, evidence on the temperature effects on childhood HFMD in temperate cities is limited, and the interactive effects of temperature and humidity have not been studied yet. METHODS: Daily counts of HFMD in children younger than 15 years of age and daily meteorologic variables during 2010 to 2012 were obtained in Hefei, China. A distributed lag nonlinear model was applied to estimate the potential nonlinear association between temperature and childhood HFMD. The interactive effects between temperature and humidity on childhood HFMD were also investigated. RESULTS: Temperature rise was associated with higher risk of childhood HFMD. Within the incubation period of HFMD, temperature rise appeared to have the acute effects on childhood HFMD, and a 5°C increase of temperature at lag 0-6 days was associated with 24.8% (95% confidence interval: 11.94%-39.10%) increase of childhood HFMD. Females and children of 0-4 years of agewere more vulnerable to temperature rise. Notably, there were obvious combined effects between temperature and humidity on childhood HFMD-the risk of childhood HFMD elevated at higher temperature and humidity level. CONCLUSIONS: This study provides evidence that temperature and humidity may jointly affect childhood HFMD, and such interactive impact needs to be considered when evaluating the temperature-childhood HFMD relationship.

Associations between extreme precipitation and childhood hand, foot and mouth disease in urban and rural areas in Hefei, China.

BACKGROUND: Understanding the relationship between extreme weather events and childhood hand, foot and mouth disease (HFMD) is important in the context of climate change. This study aimed to quantify the relationship between extreme precipitation and childhood HFMD in Hefei, China, and further, to explore whether the association varied across urban and rural areas. METHODS: Daily data on HFMD counts among children aged 0-14 years from 2010 January 1st to 2012 December 31st were retrieved from Hefei Center for Disease Control and Prevention. Daily data on mean temperature, relative humidity and precipitation during the same period were supplied by Hefei Bureau of Meteorology. We used a Poisson linear regression model combined with a distributed lag non-linear model to assess the association between extreme precipitation (≥90th precipitation) and childhood HFMD, controlling for mean temperature, humidity, day of week, and long-term trend. RESULTS: There was a statistically significant association between extreme precipitation and childhood HFMD. The effect of extreme precipitation on childhood HFMD was the greatest at six days lag, with a 5.12% (95% confident interval: 2.7-7.57%) increase of childhood HFMD for an extreme precipitation event versus no precipitation. Notably, urban children and children aged 0-4 years were particularly vulnerable to the effects of extreme precipitation. CONCLUSIONS: Our findings indicate that extreme precipitation may increase the incidence of childhood HFMD in Hefei, highlighting the importance of protecting children from forthcoming extreme precipitation, particularly for those who are young and from urban areas.