Hand, foot, and mouth disease in China: patterns of spread and transmissibility

Epidemiology of Enterovirus Genotypes in Association with Human Diseases

Enteroviruses (EVs) are well-known causes of a wide range of infectious diseases in infants and young children, ranging from mild illnesses to severe conditions, depending on the virus genotypes and the host's immunity. Recent advances in molecular surveillance and genotyping tools have identified over 116 different human EV genotypes from various types of clinical samples. However, the current knowledge about most of these genotypes, except for those of well-known genotypes like EV-A71 and EV-D68, is still limited due to a lack of comprehensive EV surveillance systems. This limited information makes it difficult to understand the true burden of EV-related diseases globally. Furthermore, the specific EV genotype associated with diseases varies according to country, population group, and study period. The same genotype can exhibit different epidemiological features in different areas. By integrating the data from established EV surveillance systems in the USA, Europe, Japan, and China, in combination with other EV infection studies, we can elaborate a better understanding of the distribution of prevalent EV genotypes and the diseases associated with EV. This review analyzed the data from various EV surveillance databases and explored the EV seroprevalence and the association of specific EV genotypes with human diseases.

Epidemiology and etiology of hand, foot, and mouth disease in Zhengzhou, China, from 2009 to 2021

Background

Hand, foot, and mouth disease (HFMD) is a common childhood infectious disease caused by a variety of enteroviruses (EVs). To explore the epidemiological characteristics and etiology of HFMD in Zhengzhou, China, we conducted a systematic analysis of HFMD surveillance data from Zhengzhou Center for Disease Control and Prevention from January 2009 to December 2021 (https://wjw.zhengzhou.gov.cn/).

Methods

Surveillance data were collected from Zhengzhou Center for Disease Control and Prevention from January 2009 to December 2021 (https://wjw.zhengzhou.gov.cn/). Cases were analyzed according to the time of onset, type of diagnosis, characteristics, viral serotype, and epidemiological trends.

Results

We found that the primary causative agent responsible for the HFMD outbreaks in Zhengzhou was Enterovirus A71 (EVA-71) (48.56%) before 2014. After 2015, other EVs gradually became the dominant strains (57.68%). The data revealed that the HFMD epidemics in Zhengzhou displayed marked seasonality, with major peaks occurring from April to June, followed by secondary peaks from October to November, except in 2020. Both the severity and case-fatality ratio of HFMD decreased following the COVID-19 pandemic (severity ‰: 13.46 vs. 0.17; case-fatality ‰: 0.21 vs. 0, respectively). Most severe cases were observed in patients aged 1 year and below, accounting for 45.81%.

Conclusions

Overall, the incidence rate of HFMD decreased in Zhengzhou following the introduction of the EVA-71 vaccine in 2016. However, it is crucial to acknowledge that HFMD prevalence continues to exhibit a distinct seasonal pattern and periodicity, and the occurrence of other EV infections poses a new challenge for children's health.

Pathogenicity and landscape of differential gene expression in mice orally infected with clinical coxsackievirus A6 (CA6)

Hand, foot, and mouth disease (HFMD) is caused by more than 20 pathogenic enteroviruses belonging to the Picornaviridae family and Enterovirus genus. Since the introduction of the enterovirus-71 (EV71) vaccine in 2016, the number of HFMD cases caused by EV71 has decreased. However, cases of infections caused by other enteroviruses, such as coxsackievirus A6 (CA6) and coxsackievirus A10, have been increasing accordingly. In this study, we used a clinical isolate of CA6 to establish an intragastric infection mouse model using 7-day-old mice to mimic the natural transmission route, by which we investigated the differential gene expression profiles associated with virus infection and pathogenicity. After intragastric infection, mice exhibited hind limb paralysis symptoms and weight loss, similar to those reported for EV71 infection in mice. The skeletal muscle was identified as the main site of virus replication, with a peak viral load reaching 2.31 × 107 copies/mg at 5 dpi and increased infiltration of inflammatory cells. RNA sequencing analysis identified differentially expressed genes (DEGs) after CA6 infection. DEGs in the blood, muscle, brain, spleen, and thymus were predominantly enriched in immune system responses, including pathways such as Toll-like receptor signaling and PI3K-Akt signaling. Our study has unveiled the genes involved in the host immune response during CA6 infection, thereby enhancing our comprehension of the pathological mechanism of HFMD.IMPORTANCEThis study holds great significance for the field of hand, foot, and mouth disease (HFMD). It not only delves into the disease's etiology, transmission pathways, and severe complications but also establishes a novel mouse model that mimics the natural coxsackievirus A6 infection process, providing a pivotal platform to delve deeper into virus replication and pathogenic mechanisms. Additionally, utilizing RNA-seq technology, it unveils the dynamic gene expression changes during infection, offering valuable leads for identifying novel therapeutic drug targets. This research has the potential to enhance our understanding of HFMD, offering fresh perspectives for disease prevention and treatment and positively impacting children's health worldwide.

A review on current diagnostic tools and potential optical absorption spectroscopy for HFMD detection

Hand, Foot, and Mouth Disease (HFMD) is an outbreak infectious disease that can easily spread among children under the age of five. The most common causative agents of HFMD are enterovirus 71 (EV71) and coxsackievirus A16 (CVA16), but infection caused by EV71 is more associated with fatalities due to severe neurological disorders. The present diagnosis methods rely on physical examinations by the doctors and further confirmation by laboratories detection methods such as viral culture and polymerase chain reaction. Clinical signs of HFMD infection and other childhood diseases such as chicken pox, and allergies are similar, yet the genetics and pathogenicity of the viruses are substantially different. Thus, there is an urgent need for an early screening of HFMD using an inexpensive and user-friendly device that can directly detect the causative agents of the disease. This paper reviews current HFMD diagnostic methods based on various target types, such as nucleic acid, protein, and whole virus. This was followed by a thorough discussion on the emerging sensing technologies for HFMD detection, including surface plasmon resonance, electrochemical sensor, and surface enhanced Raman spectroscopy. Lastly, optical absorption spectroscopic method was critically discussed and proposed as a promising technology for HFMD screening and detection.

Detecting the spatial clustering of exposure-response relationships with estimation error: a novel spatial scan statistic

Detecting the spatial clustering of the exposure-response relationship (ERR) between environmental risk factors and health-related outcomes plays important roles in disease control and prevention, such as identifying highly sensitive regions, exploring the causes of heterogeneous ERRs, and designing region-specific health intervention measures. However, few studies have focused on this issue. A possible reason is that the commonly used cluster-detecting tool, spatial scan statistics, cannot be used for multivariate spatial datasets with estimation error, such as the ERR, which is often defined by a vector with its covariance estimated by a regression model. Such spatial datasets have been produced in abundance in the last decade, which suggests the importance of developing a novel cluster-detecting tool applicable for multivariate datasets with estimation error. In this work, by extending the classic scan statistic, we developed a novel spatial scan statistic called the estimation-error-based scan statistic (EESS), which is applicable for both univariate and multivariate datasets with estimation error. Then, a two-stage analytic process was proposed to detect the spatial clustering of ERRs in practical studies. A published motivating example and a simulation study were used to validate the performance of EESS. The results show that the clusters detected by EESS can efficiently reflect the clustering heterogeneity and yield more accurate ERR estimates by adjusting for such heterogeneity.

Impact of meteorological factors on the incidence of hand-foot-mouth disease in Yangzhou from 2017 to 2022: a time series study

Background

Hand, foot, and mouth disease (HFMD) is a significant public health issue in China, and numerous studies have indicated a close association between HFMD incidence and meteorological factors. This study aims to investigate the relationship between meteorological factors and HFMD in Yangzhou City, Jiangsu Province, China.

Methods

HFMD case reports and meteorological data from Yangzhou City between 2017 and 2022 were extracted from the National Notifiable Infectious Disease Surveillance System and the Meteorological Data Sharing Service System, respectively. A generalized additive model (GAM) was employed to assess the exposure-response relationship between meteorological factors and HFMD. Subsequently, a distributed lag nonlinear model (DLNM) was used to explore the exposure-lag-effect of meteorological factors on HFMD.

Results

HFMD in Yangzhou City exhibits obvious seasonality and periodicity. There is an inverted "U" shaped relationship between average temperature and the risk of HFMD, with the maximum lag effect observed at a temperature of 25°C with lag 0 day (RR = 2.07, 95% CI: 1.74-2.47). As the duration of sunshine and relative humidity increase, the risk of HFMD continuously rises, with the maximum lag effect observed at a sunshine duration of 12.4 h with a lag of 14 days (RR = 2.10, 95% CI: 1.17-3.77), and a relative humidity of 28% with a lag of 14 days (RR = 1.21, 95% CI: 1.01-1.64). There is a "U" shaped relationship between average atmospheric pressure and the risk of HFMD, with the maximum effect observed at an atmospheric pressure of 989 hPa with no lag (RR = 1.45, 95% CI: 1.25-1.69). As precipitation increases, the risk of HFMD decreases, with the maximum effect observed at a precipitation of 151 mm with a lag of 14 days (RR = 1.45, 95% CI: 1.19-2.53).

Conclusion

Meteorological factors including average temperature, average atmospheric pressure, relative humidity, precipitation, and sunshine duration significantly influenced the risk of HFMD in Yangzhou City. Effective prevention measures for HFMD should be implemented, taking into account the local climate conditions.

Dynamic modeling and data fitting of climatic and environmental factors and people's behavior factors on hand, foot, and mouth disease (HFMD) in Shanghai, China

Background

Hand, foot, and mouth disease (HFMD) appear to be a multi-wave outbreak with unknown mechanisms. We investigate the effects of climatic and environmental factors and changes in people's behavior factors that may be caused by external factors: temperature, relative humidity, and school opening and closing.

Methods

Distributed lag nonlinear model (DLNM) and dynamic model are used to research multi-wave outbreaks of HFMD. Climatic and environmental factors impact on transmission rate β ( t ) is modeled through DLNM and then substituted into this relationship to establish the dynamic model with reported case data to test for validity.

Results

Relative risk (RR) of HFMD infection increases with increasing temperature. The RR of infection first increases and then decreases with the increase of relative humidity. For the model fitting HFMD dynamic, time average basic reproduction number [ R 0 ] of Stage I (without vaccine) and Stage II (with EV71 vaccine) are 1.9362 and 1.5478, respectively. Temperature has the highest explanatory power, followed by school opening and closing, and relative humidity.

Conclusion

We obtain three conclusions about the prevention and control of HFMD. 1) According to the temperature, relative humidity and school start time, the outbreak peak of HFMD should be warned and targeted prevention and control measures should be taken. 2) Reduce high indoor temperature when more than 31.5 oC, and increase low relative humidity when less than 77.5% by opening the window for ventilation, adding houseplants, using air conditioners and humidifiers, reducing the incidence of HFMD and the number of infections. 3) The risk of HFMD transmission during winter vacations is higher than during summer vacations. It is necessary to strengthen the publicity of HFMD prevention knowledge before winter vacations and strengthen the disinfection control measures during winter vacations in children's hospitals, school classrooms, and other places where children gather to reduce the frequency of staff turnover during winter vacations.

Association of public health and social measures on the hand-foot-mouth epidemic in South Korea

BACKGROUND

School based-measures such as school closure and school holidays have been considered a viable intervention during the hand-foot-mouth disease (HFMD) epidemic. The aim of this study was to explore the association of nationwide public health and social measures (PHSMs) including planned school vacation on the transmissibility and attack rate of the HFMD epidemic in South Korea.

METHODS

In this study, we used Korean national surveillance data on HFMD from 2014 to 2019 to estimate the temporal changes in HFMD transmissibility (instantaneous reproductive number, Rt). Furthermore, to assess the changes in the HFMD attack rate, we used a stochastic transmission model to simulate the HFMD epidemic with no school vacation and nationwide PHSMs in 2015 South Korea.

RESULTS

We found that school vacations and 2015 PHSMs were associated with the reduced Rt by 2-7 % and 13 %, respectively. Model projections indicated school vacations and 2015 PHSMs were associated with reduced HFMD attack rate by an average of 1.10 % (range: 0.38-1.51 %).

CONCLUSIONS

PHSMs likely have a larger association with reduced HFMD transmissibility than school-based measures alone (i.e. school vacations). Preventive measures targeting preschoolers could be considered as potential options for reducing the future burden of HFMD.

Study of the influence of meteorological factors on HFMD and prediction based on the LSTM algorithm in Fuzhou, China

BACKGROUND

This study adopted complete meteorological indicators, including eight items, to explore their impact on hand, foot, and mouth disease (HFMD) in Fuzhou, and predict the incidence of HFMD through the long short-term memory (LSTM) neural network algorithm of artificial intelligence.

METHOD

A distributed lag nonlinear model (DLNM) was used to analyse the influence of meteorological factors on HFMD in Fuzhou from 2010 to 2021. Then, the numbers of HFMD cases in 2019, 2020 and 2021 were predicted using the LSTM model through multifactor single-step and multistep rolling methods. The root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE) and symmetric mean absolute percentage error (SMAPE) were used to evaluate the accuracy of the model predictions.

RESULTS

Overall, the effect of daily precipitation on HFMD was not significant. Low (4 hPa) and high (≥ 21 hPa) daily air pressure difference (PRSD) and low (< 7 °C) and high (> 12 °C) daily air temperature difference (TEMD) were risk factors for HFMD. The RMSE, MAE, MAPE and SMAPE of using the weekly multifactor data to predict the cases of HFMD on the following day, from 2019 to 2021, were lower than those of using the daily multifactor data to predict the cases of HFMD on the following day. In particular, the RMSE, MAE, MAPE and SMAPE of using weekly multifactor data to predict the following week's daily average cases of HFMD were much lower, and similar results were also found in urban and rural areas, which indicating that this approach was more accurate.

CONCLUSION

This study's LSTM models combined with meteorological factors (excluding PRE) can be used to accurately predict HFMD in Fuzhou, especially the method of predicting the daily average cases of HFMD in the following week using weekly multifactor data.

Does Public Health Emergency Experience Have an Impact on Individual Reactions during COVID-19?

Local historical experience in public health emergencies has been perceived to largely affect COVID-19's social influence. Specifically, individuals' personal experience in public health emergencies would likely have an impact on their reactions to the next similar event. Herein, we combined life course and risk analysis frameworks to explore how individuals' experiences influence current risk perception and protective behaviors. We collected 1000 questionnaires of random network samples in six Chinese provinces of different risk levels from 29 April to 8 May 2020, and used the propensity score matching (PSM) model and multivariable linear regression to process the data. We categorized individual public emergency experience into three patterns: (1) having ever witnessed a public health emergency, (2) having ever experienced a public health emergency, and (3) currently experiencing a public health emergency. The study indicates that individuals' experiences had significant positive effects on protective behaviors against COVID-19. The average effects of the three patterns on behaviors were 0.371 (p < 0.001), 0.898 (p < 0.001) and 0.319 (p < 0.05), respectively. The study also shows that for those experiencing any one pattern, the effect of risk perception on protective behaviors appeared null in the early stage of the pandemic. We propose the potential interactive mechanism of risk factors in the life course at the individual level. Academically, this study develops the risk theory of perception and behavior and expands the application of the life course approach in the public health arena. Practically, our research indicates that public health emergency experiences are valuable for responding to a future pandemic and normalizing prevention policies.

Analysis of the Epidemiologic Characteristics of Children with Hand, Foot and Mouth Disease in China

Background

We aimed to investigate the epidemiological characteristics of hand, foot and mouth disease (HFMD) and provide recommendations for its control and prevention.

Methods

A descriptive epidemiological analysis was designed for HFMD in children through direct network report from 2015 to 2019.

Results

From 2015 to 2019, a total 27,395 HFMD cases were reported at Infection Clinic of Shanghai Children's Hospital, Shanghai, China, accounting for 79.24% of the number of reported notifiable infectious disease cases (34,573). The cases number increased since May and reached a peak from June to September, then decreased from October to December with a second small peak in some years. The proportion of cases in boys is higher than in girls (59.7% vs. 40.3%). The cases number of stay-at-home children was higher in 2016 and 2018 (60.07% and 60.95%) than in 2019 (33.47%), and that of kindergarten children and students in 2019 (51.73% and 9.75%) was significantly higher than in other years. Overall, 22606 cases were reported in <5 years group, accounting for 82.52% of the total number of cases during 2015-2019. The proportion of the cases in 5-10 and >10 years groups increased year by year from 2015 to 2019, which is statistically significant. (χ2=71.105, P=0.00; χ2=78.413, P=0.00).

Conclusion

The epidemiological characteristics of HFMD had changed during 2015-2019. Analysis of these data can provide helpful evidence to prevention and early treatment of the HFMD, and identification severe cases and handling the outbreaks.

Exploring the influence of COVID-19 on the spread of hand, foot, and mouth disease with an automatic machine learning prediction model

Hand, foot, and mouth disease (HFMD) is an important public health problem and has received concern worldwide. Moreover, the coronavirus disease 2019 (COVID-19) epidemic also increases the difficulty of understanding and predicting the prevalence of HFMD. The purpose is to prove the usability and applicability of the automatic machine learning (Auto-ML) algorithm in predicting the epidemic trend of HFMD and to explore the influence of COVID-19 on the spread of HFMD. The AutoML algorithm and the autoregressive integrated moving average (ARIMA) model were applied to construct and validate models, based on the monthly incidence numbers of HFMD and meteorological factors from May 2008 to December 2019 in Henan province, China. A total of four models were established, among which the Auto-ML model with meteorological factors had minimum RMSE and MAE in both the model constructing phase and forecasting phase (training set: RMSE = 1424.40 and MAE = 812.55; test set: RMSE = 2107.83, MAE = 1494.41), so this model has the best performance. The optimal model was used to further predict the incidence numbers of HFMD in 2020 and then compared with the reported cases. And, for analysis, 2020 was divided into two periods. The predicted incidence numbers followed the same trend as the reported cases of HFMD before the COVID-19 outbreak; while after the COVID-19 outbreak, the reported cases have been greatly reduced than expected, with an average of only about 103 cases per month, and the incidence peak has also been delayed, which has led to significant changes in the seasonality of HFMD. Overall, the AutoML algorithm is an applicable and ideal method to predict the epidemic trend of the HFMD. Furthermore, it was found that the countermeasures of COVID-19 have a certain influence on suppressing the spread of HFMD during the period of COVID-19. The findings are helpful to health administrative departments.

Disease burden in patients with severe hand, foot, and mouth disease in Jiangsu Province: a cross-sectional study

This study aimed to estimate the disease burden and health-related quality of life (HRQOL) among patients with severe hand, foot, and mouth disease (HFMD) in Jiangsu Province, China. We analyzed the surveillance data of HFMD cases in Jiangsu Province from 2009 to 2020. Moreover, a cross-sectional study was conducted in Nanjing and Suzhou, China, between January 2017 and May 2018. Patients with severe HFMD and their parents were recruited from selected hospitals. Questionnaires and hospital management systems were used to collect data on direct economic burden. The HRQOL of children was assessed using the TNO-AZL Preschool Quality of Life (TAPQOL) scale. A total of 1,348,737 confirmed cases of HFMD were reported to the NNDRS in Jiangsu province during 2009-2020. Of these, 9,622 were severe cases, with 62 (.64%) of these being fatal. From January 2017 to May 2018, data was collected from 362 severe HFMD cases using a structured questionnaire. The median per capita direct economic burden was RMB 16142.88, and was associated with the region and length of hospital stay (P < .05). The direct economic burden for all cases of severe HFMD in Jiangsu province between 2017 and 2018 was approximately RMB 16.64 million. Finally, the median (IQR) of the TAPQOL scale for children with severe HFMD was 69.23 (56.20, 82.27). Severe HFMD infection is a relatively large burden for individuals, and the burden of EV-A71 infection was seen to be even greater for the population. Prevention of severe HFMD should strengthen hygiene habits and targeted measures for EV-A71 vaccination.

Study on the interaction between different pathogens of Hand, foot and mouth disease in five regions of China

Objectives

This study aims to explore the interaction of different pathogens in Hand, foot and mouth disease (HFMD) by using a mathematical epidemiological model and the reported data in five regions of China.

Methods

A cross-regional dataset of reported HFMD cases was built from four provinces (Fujian Province, Jiangsu province, Hunan Province, and Jilin Province) and one municipality (Chongqing Municipality) in China. The subtypes of the pathogens of HFMD, including Coxsackievirus A16 (CV-A16), enteroviruses A71 (EV-A71), and other enteroviruses (Others), were included in the data. A mathematical model was developed to fit the data. The effective reproduction number (R _eff ) was calculated to quantify the transmissibility of the pathogens.

Results

In total, 3,336,482 HFMD cases were collected in the five regions. In Fujian Province, the R _eff between CV-A16 and EV-A71&CV-A16, and between CV-A16 and CV-A16&Others showed statistically significant differences (P < 0.05). In Jiangsu Province, there was a significant difference in R _eff (P < 0.05) between the CV-A16 and Total. In Hunan Province, the R _eff between CV-A16 and EV-A71&CV-A16, between CV-A16 and Total were significant (P < 0.05). In Chongqing Municipality, we found significant differences of the R _eff (P < 0.05) between CV-A16 and CV-A16&Others, and between Others and CV-A16&Others. In Jilin Province, significant differences of the R _eff (P < 0.05) were found between EV-A71 and Total, and between Others and Total.

Conclusion

The major pathogens of HFMD have changed annually, and the incidence of HFMD caused by others and CV-A16 has surpassed that of EV-A71 in recent years. Cross-regional differences were observed in the interactions between the pathogens.

Effect of enterovirus 71 vaccination on the epidemiological characteristics and etiology in hospitalized children with hand-foot-and-mouth disease: A retrospective study from a tertiary children's hospital

Enterovirus 71 (EV71) vaccine for hand-foot-and-mouth disease (HFMD) prevention has been available for several years. However, as a new vaccine, the impact of EV71 vaccination on the epidemiology and etiology of HFMD is currently unclear. The purpose of this study was to compare and analyze the changes of epidemiological characteristics and etiology of HFMD patients after the introduction of EV71 vaccine. The data of hospitalized children with HFMD from 2014 to 2020 were collected from the case record department of a tertiary children hospital of Anhui Province. The changes of epidemiological characteristics, time distribution, disease severity and enterovirus serotypes in hospitalized children were analyzed. A total of 7373 cases of HFMD were reported during 2014 to 2020, including 634 (8.6%) severe cases. The number of cases reached the peak in 2016 (n = 1783) and decreased gradually after EV71 vaccination. The results of etiological test showed the positive rate was 80.5%, in which EV71 accounted for 1599 (21.7%) and CV-A16 accounted for 1028 (13.9%) respectively. The number of patients showed a bimodal distribution throughout the year, which were April to June and October to November. The age distribution changed significantly following the introduction of EV71 vaccine. The proportion of 1-year-old group of post-vaccination was significantly higher than that of pre-vaccination (61.9% vs 50.8%, P < .001). The proportion of HFMD caused by EV71 and severe cases decreased significantly after the vaccination (P < .001 for both). While the comparison of epidemiological characteristics and enterovirus serotypes between unvaccinated and vaccinated cases during 2017 to 2020 showed no significant difference. The dominant enterovirus serotypes of hospitalized HFMD changed significantly after the introduction of EV71 vaccine. The proportion of severe cases decreased significantly after the vaccination, but EV71 was still a major pathogen in patients with severe HFMD. More age-appropriate children are recommended to get vaccinated to establish stronger herd immunity in the population.

Molecular epidemiology of enteroviruses associated with hand, foot, and mouth disease in South India from 2015 to 2017

Hand, foot, and mouth disease (HFMD) is a common childhood infection caused by human enteroviruses and is clinically characterised by fever with vesicular rash on the hands, feet, and mouth. While enterovirus A71 (EV-A71) and coxsackievirus A16 (CVA16) were the major etiological agents of HFMD in India earlier, the data on recently circulating enteroviruses associated with HFMD are sparse. Here, we describe the molecular epidemiology of enteroviruses associated with HFMD in South India from 2015 to 2017. We used archived enterovirus real-time reverse transcription (RT) PCR-positive vesicle swab and/or throat swab specimens from clinically suspected HFMD cases collected from four secondary-care hospitals in South India between July 2015 and December 2017. PCR amplification and sequencing were done based on the 5’VP1, 3’VP1, VP2, or 5´NCR regions to identify enterovirus types. Genetic diversity among enteroviruses was inferred by phylogenetic analysis. Of the 107 enterovirus RNA real-time RT-PCR-positive HFMD cases, 69 (64%) were typed as CVA6, 16 (15%) were CVA16, and one (1%) was CVA10, whereas in 21 (20%) cases, the virus was not typeable by any of the methods used in the study. The majority of HFMD cases (89, 83%) were in children less than five years old, while 11 (10.3%) were in adults. 5’VP1 yielded the maximum number of enteroviruses genotyped, and phylogenetic analysis showed that the CVA6 strains belonged to subclade D3, while the subclades of CVA16 and CVA10 were B1c and D, respectively. The predominant etiological agent of HFMD in South India during 2015-2017 was CVA6, followed by CVA16 and CVA10.

Effects of Meteorological Factors and Atmospheric Pollution on Hand, Foot, and Mouth Disease in Urumqi Region

Background

Hand, foot, and mouth disease (HFMD) is a febrile rash infection caused by enteroviruses, spreading mainly via the respiratory tract and close contact. In the past two decades, HFMD has been prevalent mainly in Asia, including China and South Korea, causing a huge disease burden and putting the lives and health of children at risk. Therefore, a further study of the factors influencing HFMD incidences has far-reaching implications. In existing studies, the environmental factors affecting such incidences are mainly divided into two categories: meteorological and air. Among these studies, the former are the majority of studies on HFMD. Some scholars have studied both factors at the same, but the number is not large and the findings are quite different.

Methods

We collect monthly cases of HFMD in children, meteorological factors and atmospheric pollution in Urumqi from 2014 to 2020. Trend plots are used to understand the approximate trends between meteorological factors, atmospheric pollution and the number of HFMD cases. The association between meteorological factors, atmospheric pollution and the incidence of HFMD in the Urumqi region of northwest China is then investigated using multiple regression models.

Results

A total of 16,168 cases in children are included in this study. According to trend plots, the incidence of HFMD shows a clear seasonal pattern, with O3 (ug/m3) and temperature (°C) showing approximately the same trend as the number of HFMD cases, while AQI, PM2.5 (ug/m3), PM10 (ug/m3) and NO2 (ug/m3) all show approximately opposite trends to the number of HFMD cases. Based on multiple regression results, O3 (P = 0.001) and average station pressure (P = 0.037) are significantly and negatively associated with HFMD incidences, while SO2 (P = 0.102), average dew point temperature (P = 0.072), hail (P = 0.077), and thunder (P = 0.14) have weak significant relationships with them.

Epidemiological characteristics, routine laboratory diagnosis, clinical signs and risk factors for hand, -foot -and -mouth disease: A systematic review and meta-analysis

Background

For the past few years, only a few monovalent EV71 vaccines have been developed, while other enterovirus vaccines are in short supply. We conducted a quantitative meta-analysis to explore the epidemiological characteristics, routine laboratory diagnosis, clinical signs and risk factors for hand, foot and mouth disease (HFMD).

Methods

PubMed, Embase and the Web of Science were searched for eligible reports published before April 16, 2021, with no publication time or language restrictions. The primary outcome was the odds ratio of the epidemiological characteristics, routine laboratory diagnosis, and clinical signs associated with HFMD severity and death.

Results

After screening 10522 records, we included 32 articles comprising 781903 cases of hand, foot and mouth disease. Patients with severe illness developed some clinical signs (hypersomnia (OR = 21.97, 95% CI: 4.13 to 116.74), convulsion (OR = 16.18, 95% CI: 5.30 to 49.39), limb shaking (OR = 47.96, 95% CI: 15.17 to 151.67), and breathlessness (OR = 7.48, 95% CI: 1.90 to 29.40)) and had some changes in laboratory parameters (interleukin-6 levels standardized mean difference (SMD) = 1.57, 95%CI: 0.55 to 2.60), an increased neutrophils ratio (SMD = 0.55, 95%CI: 0.17 to 0.93), cluster of differentiation 4 (CD4+) (SMD = -1.38, 95%CI: -2.33 to -0.43) and a reduced lymphocytes ratio (SMD = -0.48, 95%CI: -0.93 to -0.33)) compared with patients with mild illness. The risk factors for death included cyanosis (OR = 5.82, 95% CI: 2.29 to 14.81), a fast heart rate (OR = 3.22, 95% CI: 1.65 to 6.30), vomiting (OR = 2.70, 95% CI: 1.33 to 5.49) and an increased WBC count (SMD = 0.60, 95% CI: 0.27 to 0.93).

Conclusions

China has the highest incidence of HFMD. Our meta-analyses revealed important risk factors that are associated with the severity and mortality of HFMD.

Efficacy, safety, and immunogenicity of an inactivated, adjuvanted enterovirus 71 vaccine in infants and children: a multiregion, double-blind, randomised, placebo-controlled, phase 3 trial

BACKGROUND

Children are susceptible to severe or fatal enterovirus 71 (EV71) infections. We aimed to evaluate the efficacy, safety, and immunogenicity of EV71vac, an aluminium phosphate-adjuvanted inactivated EV71 vaccine in children aged 2-71 months.

METHODS

We did a randomised, double-blinded, placebo-controlled, phase 3 trial at five hospitals in Taiwan and two in Vietnam. Children aged 2-71 months were stratified by country and age, and randomly assigned (1:1) to receive two doses of EV71vac or placebo via intramuscular injection 56 days apart. Children aged 2-23 months received a third booster dose on day 366. The primary endpoint was the clinical efficacy of the total vaccinated cohort against EV71-associated diseases during the follow-up period, from 14 days after the second dose to when 15 cases of EV71 infections were confirmed in the per-protocol population. Our safety analysis included all participants who received at least one dose of EV71vac. This trial is registered with ClinicalTrials.gov, NCT03865238, and is complete.

FINDINGS

Between April 23 and Dec 25, 2019, of 3663 children assessed, 3061 were randomly assigned, of whom 3049 were vaccinated: 1521 children in the EV71vac group and 1528 in the placebo group. By May 20, 2021, our primary efficacy analysis included 2959 children, with 1476 children in the EV71vac group and 1483 children in the placebo group. The vaccine efficacy of EV71vac was 96·8% (95% CI 85·5-100) against EV71 associated diseases (p<0·0001). The percentage of participants who reported solicited adverse events were similar in both groups: 865 (56·9%) in the EV71vac group and 852 (55·8%) in the placebo group. Almost all reported solicited adverse events were mild and self-limited.

INTERPRETATION

EV71vac is safe, well-tolerated, and highly effective in preventing EV71 associated diseases in children aged 2-71 months.

FUNDING

Medigen Vaccine Biologics and A+ Industrial Innovative R&D Program of the Ministry of Economic Affairs, Taiwan.

Changing serotypes of hand, foot and mouth disease in Shanghai, 2017-2019

BACKGROUND

Hand, foot, and mouth disease (HFMD) is a common reportable infectious disease that is highly contagious among children in China. This study aimed to characterize the epidemics of HFMD and the serotypes of enterovirus (EV) after the introduction of EV-A71 vaccines in Shanghai, a city in Eastern China.

RESULTS

A total of 2271 HFMD cases were recruited in this study from May 2017 through October 2020. Among these cases, a male-to-female ratio of 1.6:1 was observed, and the cases were mainly in 1-4 years old (63.1%). Children of all ages had a relatively similar time span between the onset of HFMD and the initial medical visit (P = 0.5192). The cases were reported year-round with peaks in the summer (2018 and 2019) and fall (2017), which was consistent with previous epidemics of the reported HFMD cases in the Shanghai municipality. Among the specimens that tested positive for EV (n = 1855), CV-A6 was predominantly detected (71.1%), followed by CV-A16 (14.2%) and EV-A71 (7.0%). Notably, the number of HFMD cases infected with EV-A71 increased in 2019. Furthermore, 9.2% of the cases had comorbidities, mostly convulsion, bronchopneumonia, and pneumonia; however, they were not correlated with the EV serotypes. In addition, 31.2% (709/2271) of the cases were vaccinated with EV-A71 vaccines. The time span differed significantly between the time of vaccination and the onset of the disease across the groups based on whether the onset was before or after vaccination (P < 0.001).

CONCLUSIONS

CV-A6 is the predominant EV serotype in the epidemic of HFMD in Shanghai; in addition, CV-A16 and EV-A71 may be moderately prevalent. The changing trends in the presence of EV serotypes contributes to the periodicity of the HFMD epidemic. In addition, the minority of HFMD cases may have comorbidities, regardless of the EV serotype. The use of the EV-A71 vaccine has affected the HFMD epidemic. And serotype-specific protection by the EV-A71 vaccine may promote vaccination in children infected with EV-A71 compared to those infected with non-EV-A71 serotypes, which would further change the epidemic scenario of HFMD.

Impact of the coronavirus disease 2019 interventions on the incidence of hand, foot, and mouth disease in mainland China

Background

In early 2020, non-pharmaceutical interventions (NPIs) were implemented in China to reduce and contain the coronavirus disease 2019 (COVID-19) transmission. These NPIs might have also reduced the incidence of hand, foot, and mouth disease (HFMD).

Methods

The weekly numbers of HFMD cases and meteorological factors in 31 provincial capital cities and municipalities in mainland China were obtained from Chinese Center for Disease Control and Prevention (CCDC) and National Meteorological Information Center of China from 2016 to 2020. The NPI data were collected from local CDCs. The incidence rate ratios (IRRs) were calculated for the entire year of 2020, and for January-July 2020 and August-December 2020. The expected case numbers were estimated using seasonal autoregressive integrated moving average models. The relationships between kindergarten closures and incidence of HFMD were quantified using a generalized additive model. The estimated associations from all cities were pooled using a multivariate meta-regression model.

Findings

Stringent NPIs were widely implemented for COVID-19 control from January to July 2020, and the IRRs for HFMD were less than 1 in all 31 cities, and less than 0·1 for 23 cities. Overall, the proportion of HFMD cases reduced by 52·9% (95% CI: 49·3-55·5%) after the implementation of kindergarten closures in 2020, and this effect was generally consistent across subgroups.

Interpretation

The decrease in HFMD incidence was strongly associated with the NPIs for COVID-19. HFMD epidemic peaks were either absent or delayed, and the final epidemic size was reduced. Kindergarten closure is an intervention to prevent HFMD outbreaks.

Funding

This research was supported by the National Natural Science Foundation of China (81973102 & 81773487), Public Health Talents Training Program of Shanghai Municipality (GWV-10.2-XD21), the Shanghai New Three-year Action Plan for Public Health (GWV-10.1-XK16), the Major Project of Scientific and Technical Winter Olympics from National Key Research and Development Program of China (2021YFF0306000), 13th Five-Year National Science and Technology Major Project for Infectious Diseases (2018ZX10725-509) and Key projects of the PLA logistics Scientific research Program (BHJ17J013).

Long-term effects of weather condition and air pollution on acute hemorrhagic conjunctivitis in China: A nationalwide surveillance study in China

BACKGROUND

Global climate change could have potential impact on enterovirus (EV)-induced infectious diseases. However, the environmental factors promoting acute hemorrhagic conjunctivitis (AHC) circulation remain inconclusive. This study aimed to quantify the relationship between the environment and AHC.

METHODS

We retrieved the monthly counts and incidence of AHC, meteorological variables and air quality in mainland China between 2013 and 2018. Exposure risks were evaluated by multivariate distributed lag nonlinear models.

RESULTS

A total of 219,599 AHC cases were reported in 31 provinces of China, predominantly in southern and central China, seasonally increased in summer. AHC incidence increased by 7% between 2013 and 2018, from 2.6873 to 2.7570 per 100,000 people. A moderate positive correlation was seen between AHC and monthly mean temperature, relative humidity (RH) and precipitation. Each unit increment was associated with a relative risk for AHC of 1.058 at 17°-32 °C at lag 0 months, 1.017 at 65-71% RH at lag 1.4 months, and 1.039 at 400-569 mm at lag 2.4 months. By contrast, a negative correlation was seen between monthly ambient NO₂ and AHC.

CONCLUSION

Long-term exposure to higher mean temperature, RH and precipitation were associated with an increased risk of AHC. The general public, especially susceptible populations, should pay close attention to weather changes and take protective measures in advance to any AHC outbreak as the above situations occur.

Spatiotemporal characters and influence factors of hand, foot and mouth epidemic in Xinjiang, China

Hand, foot and mouth (HFM) disease is a common childhood illness. The paper aims to capture the spatiotemporal characters, and investigate the influence factors of the HFM epidemic in 15 regions of Xinjiang province from 2008 to 2017, China. Descriptive statistical analysis shows that the children aged 0-5 years have a higher HFM incidence, mostly boys. The male-female ratio is 1.5:1. Through the scanning method, we obtain the first cluster high-risk areas. The cluster time is usually from May to August every year. A spatiotemporal model is proposed to analyze the impact of meteorological factors on HFM disease. Comparing with the spatial model, the model is more effective in terms of R², AIC, deviation, and mean-square error. Among meteorological factors, the number of HFM cases generally increases with the intensity of rainfall. As the temperature increases, there are more HFM patients. Some regions are mostly influenced by wind speed. Further, another spatiotemporal model is introduced to investigate the relationship between HFM disease and socioeconomic factors. The results show that socioeconomic factors have significant influence on the disease. In most areas, the risk of HFM disease tends to rise with the increase of the gross domestic product, the ratios of urban population and tertiary industry. The incidence is closely related to the number of beds and population density in some regions. The higher the ratio of primary school, the lower the number of HFM cases. Based on the above analysis, it is the key measure to prevent and control the spread of the HFM epidemic in high-risk areas, and influence factors should not be ignored.

First evidence of enterovirus A71 and echovirus 30 in Uruguay and genetic relationship with strains circulating in the South American region

Human enteroviruses (EVs) comprise more than 100 types of coxsackievirus, echovirus, poliovirus and numbered enteroviruses, which are mainly transmitted by the faecal-oral route leading to diverse diseases such as aseptic meningitis, encephalitis, and acute flaccid paralysis, among others. Since enteroviruses are excreted in faeces, wastewater-based epidemiology approaches are useful to describe EV diversity in a community. In Uruguay, knowledge about enteroviruses is extremely limited. This study assessed the diversity of enteroviruses through Illumina next-generation sequencing of VP1-amplicons obtained by RT-PCR directly applied to viral concentrates of 84 wastewater samples collected in Uruguay during 2011-2012 and 2017-2018. Fifty out of the 84 samples were positive for enteroviruses. There were detected 27 different types belonging to Enterovirus A species (CVA2-A6, A10, A16, EV-A71, A90), Enterovirus B species (CVA9, B1-B5, E1, E6, E11, E14, E21, E30) and Enterovirus C species (CVA1, A13, A19, A22, A24, EV-C99). Enterovirus A71 (EV-A71) and echovirus 30 (E30) strains were studied more in depth through phylogenetic analysis, together with some strains previously detected by us in Argentina. Results unveiled that EV-A71 sub-genogroup C2 circulates in both countries at least since 2011-2012, and that the C1-like emerging variant recently entered in Argentina. We also confirmed the circulation of echovirus 30 genotypes E and F in Argentina, and reported the detection of genotype E in Uruguay. To the best of our knowledge this is the first report of the EV-A71 C1-like emerging variant in South-America, and the first report of EV-A71 and E30 in Uruguay.

Spatial-temporal heterogeneity and meteorological factors of hand-foot-and-mouth disease in Xinjiang, China from 2008 to 2016

The study aims to depict the temporal and spatial distributions of hand-foot-and-mouth disease (HFMD) in Xinjiang, China and reveal the relationships between the incidence of HFMD and meteorological factors in Xinjiang. With the national surveillance data of HFMD in Xinjiang and meteorological parameters in the study area from 2008 to 2016, in GeoDetector Model, we examined the effects of meteorological factors on the incidence of HFMD in Xinjiang, China, tested the spatial-temporal heterogeneity of HFMD risk, and explored the temporal-spatial patterns of HFMD through the spatial autocorrelation analysis. From 2008 to 2016, the HFMD distribution showed a distinct seasonal pattern and HFMD cases typically occurred from May to July and peaked in June in Xinjiang. Relative humidity, precipitation, barometric pressure and temperature had the more significant influences on the incidence of HFMD than other meteorological factors with the explanatory power of 0.30, 0.29, 0.29 and 0.21 (P<0.000). The interaction between any two meteorological factors had a nonlinear enhancement effect on the risk of HFMD. The relative risk in Northern Xinjiang was higher than that in Southern Xinjiang. Global spatial autocorrelation analysis results indicated a fluctuating trend over these years: the positive spatial dependency on the incidence of HFMD in 2008, 2010, 2012, 2014 and 2015, the negative spatial autocorrelation in 2009 and a random distribution pattern in 2011, 2013 and 2016. Our findings revealed the correlation between meteorological factors and the incidence of HFMD in Xinjiang. The correlation showed obvious spatiotemporal heterogeneity. The study provides the basis for the government to control HFMD based on meteorological information. The risk of HFMD can be predicted with appropriate meteorological factors for HFMD prevention and control.

Caregivers: the potential infection resources for the sustaining epidemic of hand, foot, and mouth disease/herpangina in Guangdong, China?

BACKGROUND

Although several measures have been taken to control hand foot and mouth disease (HFMD) and herpangina (HA), these two diseases have been prevalent in China for 10 years with high incidence. We suspected that adults' inapparent infection might be the cause of the continued prevalence of HFMD/HA infection in mainland China.

METHODS

To explore the role of adults (especially caregivers) in the transmission process of HFMD/HA among children, 330 HFMD/HA cases and 330 healthy children (controls) were selected for a case-control study. Then, data were analyzed by logistic regression.

RESULTS

Single-variable analyses revealed that caregivers who tested positive for enterovirus was a significant risk factor of HFMD/HA transmission to children (adjusted odds ratio (OR) = 9.22; 95% CI, 1.16 to 73.23). In the final multivariable model, caregiver behavior, such as cooling children's food with mouth (OR = 1.85; 95% CI, 1.11 to 3.08) and feeding children with their own tableware (OR = 2.19; 95% CI, 1.07 to 4.45), significantly increased the risk of transmitting HFMD/HA to children. On the contrary, washing hands before feeding children reduced such risk.

CONCLUSIONS

These results implied that the caregivers might be the infectious source or carriers of enterovirus. Therefore, preventing or treating the caregivers' enterovirus infection and improving their hygiene habits, especially when they are in contact with children, could provide a breakthrough for the effective control of HFMD/HA.

Spatial-temporal mapping and risk factors for hand foot and mouth disease in northwestern inland China

Background

Hand foot and mouth disease (HFMD) is becoming one of the common human infectious diseases in China. Previous studies have described HFMD in tropical or coastal areas of Asia-Pacific countries. However, limited studies have thoroughly studied the epidemiology and potential risk factors for HFMD in inland areas with complex environmental conditions.

Methodology/Principal findings

Using the data from 2009 to 2018 on reported cases of Xinjiang Uighur Autonomous Region, we characterized the epidemic features of HFMD. Panel negative binomial model was used to identify climate, geographical and demographic determinants for HFMD incidence. A total of 70856 HFMD cases (average annual incidence: 305 per million persons) were reported in Xinjiang during the 10-year study period, of which 10393 (14.7%) were laboratory-confirmed and 98 (0.1%) were severe. HFMD peaked in summer every year during the study period, and incidence in 2012, 2015, 2016 and 2018 had minor peaks in autumn. After adjusting the school or holiday month, multiple factors were found to affect HFMD epidemiology: urban area being major land cover type (incidence risk ratio, IRR 2.08; 95% CI 1.50, 2.89), higher gross domestic product per capita (IRR 1.14; 95% CI 1.11, 1.16), rise in monthly average temperature (IRR 1.65; 95% CI 1.61, 1.69) and monthly accumulative precipitation (IRR 1.20; 95% CI 1.16, 1.24) predicted increase in the incidence of HFMD; farmland being major land cover type (IRR 0.72; 95% CI 0.64, 0.81), an increase of percentage of the minority (IRR 0.91; 95% CI 0.89, 0.93) and population density (IRR 0.98; 95% CI 0.98, 0.99) were related to a decrease in the incidence of HFMD.

Conclusions/Significance

In conclusion, the epidemic status of HFMD in Xinjiang is characterized by low morbidity and fatality. Multiple factors have significant influences on the occurrence and transmission of HFMD in Xinjiang.

Hand foot and mouth disease (HFMD) is one of the common human infectious disease threating Asia-Pacific countries. To explore the epidemiology and environmental risk factors for HFMD in inland China, we utilized 10-year HFMD surveillance data in Xinjiang Uighur Autonomous Region and combined multiple spatial-temporal statistical analyses. We identified spatial-temporal clusters of HFMD incidence and found that multiple factors could affect HFMD incidence: urban area being major land cover type, higher gross domestic product per capita, rise in monthly average temperature and monthly accumulative precipitation predicted increase in the incidence of HFMD; farmland being major land cover type, an increase of percentage of the minority and population density were related to a decrease in the incidence of HFMD. Our findings facilitate the understanding of HFMD epidemiology and risk factors in different geographic regions, which are crucial for conducting prevention and control strategies of HFMD.

An unusual location of hand, foot and mouth disease

Hand, foot, and mouth disease (HFMD) is a childhood febrile disease. Oral lesions and papulovesicular lesions on the hands and feet are the clinical signs of the disease. In our case, a 17-year-old boy presented to the emergency department, where he was diagnosed with HFMD. After 6 days, he felt intense pain in his right testicle, and therefore an ultrasound (US) examination was performed. US detected a hypoechoic mass-like area in the right testis. Viral etiology was suspected, and no therapy was prescribed. After a little more than 3 months, US examination showed a reduced lesion size. Viral epididymo-orchitis should be suspected in young men with a recent history of HFMD and testicular pain.

The fluid management and hemodynamic characteristics of PiCCO employed on young children with severe hand, foot, and mouth disease-a retrospective study

BACKGROUND

Hand, foot, and mouth disease (HFMD) is an acute infectious disease caused by human enterovirus 71 (EV71), coxsackievirus, or echovirus, which is particularly common in preschool children. Severe HFMD is prone to cause pulmonary edema before progressing to respiratory and circulatory failure; thus hemodynamic monitoring and fluid management are important to the treatment process.

METHODS

We did a review of young patients who had been successfully treated in our department for severe HFMD, which had been caused by EV71. A total of 20 patients met the inclusion criteria. Eight cases were monitored by the pulse indicator continuous cardiac output (PiCCO) technique, and fluid management was administered according to its parameters. With regard to the treatment with PiCCO monitoring, patients were divided into two groups: the PiCCO group (8 patients) and the control group (12 patients). The groups were then compared comprehensively to evaluate whether PiCCO monitoring could improve patients' clinical outcomes.

RESULTS

After analysis, the findings informed that although PiCCO failed to shorten the length of ICU stay, reduce the days of vasoactive drug usage, or lower the number of cases which required mechanical ventilation, PiCCO did reduce the incidence of fluid overload (p = 0.085) and shorten the days of mechanical ventilation (p = 0.028). After effective treatment, PiCCO monitoring indicated that the cardiac index (CI) increased gradually(p < 0.0001), in contrast to their pulse (P, p < 0.0001), the extra vascular lung water index (EVLWI, p < 0.0001), the global end diastolic volume index (GEDVI, p = 0.0043), and the systemic vascular resistance index (SVRI, p < 0.0001), all of which decreased gradually.

CONCLUSION

Our study discovered that PiCCO hemodynamic monitoring in young children with severe HFMD has some potential benefits, such as reducing fluid overload and the duration of mechanical ventilation. However, whether it can ameliorate the severity of the disease, reduce mortality, or prevent multiple organ dysfunction remain to be further investigated.

EV71 vaccination impact on the incidence of encephalitis in patients with hand, foot and mouth disease

In order to analyze the effect of EV71 vaccination on the incidence of encephalitis in patients with HFMD, 292 cases were vaccinated, and 2,486 cases were not vaccinated which were collected in 2018 and 2019. It shows that the incidence rate of encephalitis in vaccinated patients was significantly lower than that in non-vaccinated (P = .028), which suggests that EV71 vaccine has a protective effect on the occurrence of encephalitis. But some EV71 vaccinated patients still developed into encephalitis showed that they had not produced protection or protection was weak against EV71-related encephalitis; the reasons require further investigation.

Trend analysis and forecast of daily reported incidence of hand, foot and mouth disease in Hubei, China by Prophet model

Hand, foot, and mouth disease (HFMD) is common among children below 5 years. HFMD has a high incidence in Hubei Province, China. In this study, the Prophet model was used to forecast the incidence of HFMD in comparison with the autoregressive-integrated moving average (ARIMA) model, and HFMD incidence was decomposed into trends, yearly, weekly seasonality and holiday effect. The Prophet model fitted better than the ARIMA model in daily reported incidence of HFMD. The HFMD incidence forecast by the Prophet model showed that two peaks occurred in 2019, with the higher peak in May and the lower peak in December. Periodically changing patterns of HFMD incidence were observed after decomposing the time-series into its major components. In specific, multi-year variability of HFMD incidence was found, and the slow-down increasing point of HFMD incidence was identified. Relatively high HFMD incidences appeared in May and on Mondays. The effect of Spring Festival on HFMD incidence was much stronger than that of other holidays. This study showed the potential of the Prophet model to detect seasonality in HFMD incidence. Our next goal is to incorporate climate variables into the Prophet model to produce an accurate forecast of HFMD incidence.

Regional-level risk factors for severe hand-foot-and-mouth disease: an ecological study from mainland China

Background

Severe hand-foot-and-mouth disease (HFMD) is a life-threatening contagious disease among young children and infants. Although enterovirus A71 has been well acknowledged to be the dominant cause of severe HFMD, there still remain other unidentified risk factors for severe HFMD. Previous studies mainly focused on identifying the individual-level risk factors from a clinical perspective, while rare studies aimed to clarify the association between regional-level risk factors and severe HFMD, which may be more important from a public health perspective.

Methods

We retrieved the clinical HFMD counts between 2008 and 2014 from the Chinese Center for Disease Control and Prevention, which were used to calculated the case-severity rate in 143 prefectural-level cities in mainland China. For each of those 143 cities, we further obtained city-specific characteristics from the China City Statistical Yearbook (social and economic variables) and the national meteorological monitoring system (meteorological variables). A Poisson regression model was then used to estimate the associations between city-specific characteristics (reduced by the principal component analysis to avoid multicollinearity) and the case-severity rate of HFMD. The above analysis was further stratified by age and gender to examine potential modifying effects and vulnerable sub-populations.

Results

We found that the case-severity rate of HFMD varied dramatically between cities, ranging from 0 to 8.09%. Cities with high case-severity rates were mainly clustered in Central China. By relating the case-severity rate to city-specific characteristics, we found that both the principal component characterized by a high level of social and economic development (RR = 0.823, 95%CI 0.739, 0.916) and another that characterized by warm and humid climate (RR = 0.771, 95%CI 0.619, 0.960) were negatively associated with the case-severity rate of HFMD. These estimations were consistent across age and gender sub-populations.

Conclusion

Except for the type of infected pathogen, the case-severity rate of HFMD was closely related to city development and meteorological factor. These findings suggest that social and environmental factors may also play an important role in the progress of severe HFMD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12199-020-00927-9.

Transmission pattern of shigellosis in Wuhan City, China: a modelling study

The article aims to estimate and forecast the transmissibility of shigellosis and explore the association of meteorological factors with shigellosis. The mathematical model named Susceptible–Exposed–Symptomatic/Asymptomatic–Recovered–Water/Food (SEIARW) was used to explore the feature of shigellosis transmission based on the data of Wuhan City, China, from 2005 to 2017. The study applied effective reproduction number (R_eff) to estimate the transmissibility. Daily meteorological data from 2008 to 2017 were used to determine Spearman's correlation with reported new cases and R_eff. The SEIARW model fit the data well (χ² = 0.00046, p > 0.999). The simulation results showed that the reservoir-to-person transmission of the shigellosis route has been interrupted. The R_eff would be reduced to a transmission threshold of 1.00 (95% confidence interval (CI) 0.82–1.19) in 2035. Reducing the infectious period to 11.25 days would also decrease the value of R_eff to 0.99. There was a significant correlation between new cases of shigellosis and atmospheric pressure, temperature, wind speed and sun hours per day. The correlation coefficients, although statistically significant, were very low (<0.3). In Wuhan, China, the main transmission pattern of shigellosis is person-to-person. Meteorological factors, especially daily atmospheric pressure and temperature, may influence the epidemic of shigellosis.

Early Evidence of Inactivated Enterovirus 71 Vaccine Impact Against Hand, Foot, and Mouth Disease in a Major Center of Ongoing Transmission in China, 2011-2018: A Longitudinal Surveillance Study

BACKGROUND

Enterovirus 71 (EV71) is a major causative agent of hand, foot, and mouth disease (HFMD), associated with severe manifestations of the disease. Pediatric immunization with inactivated EV71 vaccine was initiated in 2016 in the Asia-Pacific region, including China. We analyzed a time series of HFMD cases attributable to EV71, coxsackievirus A16 (CA16), and other enteroviruses in Chengdu, a major transmission center in China, to assess early impacts of immunization.

METHODS

Reported HFMD cases were obtained from China's notifiable disease surveillance system. We compared observed postvaccination incidence rates during 2017-2018 with counterfactual predictions made from a negative binomial regression and a random forest model fitted to prevaccine years (2011-2015). We fit a change point model to the full time series to evaluate whether the trend of EV71 HFMD changed following vaccination.

RESULTS

Between 2011 and 2018, 279 352 HFMD cases were reported in the study region. The average incidence rate of EV71 HFMD in 2017-2018 was 60% (95% prediction interval [PI], 41%-72%) lower than predicted in the absence of immunization, corresponding to an estimated 6911 (95% PI, 3246-11 542) EV71 cases averted over 2 years. There were 52% (95% PI, 42%-60%) fewer severe HFMD cases than predicted. However, the incidence rate of non-CA16 and non-EV71 HFMD was elevated in 2018. We identified a significant decline in the trend of EV71 HFMD 4 months into the postvaccine period.

CONCLUSIONS

We provide the first real-world evidence that programmatic vaccination against EV71 is effective against childhood HFMD and present an approach to detect early vaccine impact or intended consequences from surveillance data.

Basic Reproduction Number of Enterovirus 71 Coxsackievirus A16 and A6: Evidence from Outbreaks of Hand, Foot and Mouth Disease in China between 2011 and 2018

BACKGROUND

Enterovirus 71 (EV-A71), Coxsackievirus A16 (CV-A16) and Coxsackievirus A6 (CV-A6) are common serotypes causing hand, foot, and mouth disease (HFMD). Analyses on the basic reproduction number (R0) of common pathogens causing HFMD are limited and there are no related studies using field data from outbreaks in mainland China.

METHODS

We estimated the pathogen-specific basic reproduction number based on laboratory-confirmed HFMD outbreaks (clusters of ≥10 HFMD cases) reported to the national surveillance system between 2011 and 2018. The reproduction numbers were calculated using a mathematical model and the cumulative cases during the initial growth periods.

RESULTS

This study included 539 outbreaks, of which 198 were caused by EV-A71, 316 by CV-A16, and 25 by CV-A6. All 10417 cases involved were children. Assuming the outbreaks occurred in closed systems and the incubation period is 5 days, the median R0s of EV-A71, CV-A16, and CV-A6 were 5.06 [2.81, 10.20], 4.84 [3.00, 9.00] and 5.94 [3.27, 10.00] (Median [IQR]). After adjusting for seroprevalences, the R0s for EV-A71, CV-A16 (optimistic and conservative scenarios), and CV-A6 were 12.60 [IQR: 7.35, 25.40], 9.29 [IQR: 6.01, 19.20], 15.50 [IQR: 9.77, 30.40], and 25.80 [IQR: 14.20, 43.50], respectively. We did not observe changes in the R0s of EV-A71 after vaccine licensure (p-value = 0.67).

CONCLUSIONS

HFMD is highly transmissible when caused by the three most common serotypes. In mainland China, it primarily affects young children. Although a vaccine became available in 2016, we have not yet observed any related changes in the disease dynamics.

Risk factors for severe hand, foot, and mouth disease infected with Coxsackievirus A6: A hospital-based case-control study

Coxsackievirus 6 (CV-A6) has been emerging as another predominant serotype for severe hand, foot, and mouth disease (HFMD) in China, after the introduction of enterovirus 71 inactivated vaccine (EV71 vaccine) for 3 years. Data on the risk factors for severe HFMD infected with CV-A6 are limited. We interviewed the caregivers to collected data on HFMD patients who sought medical care in the People's Hospital of Baoan district, Shenzhen, from 2015 to 2017. Totally, 131 severe patients were frequency-matched by age and gender with 174 mild patients infected with CV-A6. Univariable and multivariable logistic regression analyses were conducted to analyze the risk factors for severe CV-A6 HFMD. The average age was 20.62 ± 14.18 months and 20.52 ± 12.76 months for severe and mild patients, respectively. Multivariate analyses indicated complications at birth (odds ratio [OR], 4.18; 95% confidence interval [CI]: 1.64-10.63), peak body temperature over 39°C (OR, 4.04; 95% CI: 2.29-7.10) and first-born child (OR, 2.17; 95% CI: 1.27-3.70) increased the risk of severe HFMD infected with CV-A6. Breastfeeding (OR, 0.52; 95% CI: 0.32-0.87), and washing hands after playing frequently (OR, 0.58; 95% CI: 0.34-0.97) were negatively associated with severe illness. Compared with HFMD with infection of EV-A71, complications at birth and first-born child were newly found to be associated with severe illness in HFMD patients infected with CV-A6.

Short-term effects of rainfall on childhood hand, foot and mouth disease and related spatial heterogeneity: evidence from 143 cities in mainland China

BACKGROUND

Numerous studies have demonstrated the potential association between rainfall and hand, foot and mouth disease (HFMD), but the results are inconsistent. This study aimed to quantify the relationship between rainfall and HFMD based on a multicity study and explore the potential sources of spatial heterogeneity.

METHODS

We retrieved the daily counts of childhood HFMD and the meteorological variables of the 143 cities in mainland China between 2009 and 2014. A common time series regression model was applied to quantify the association between rainfall and HFMD for each of the 143 cities. Then, we adopted the meta-regression model to pool the city-specific estimates and explore the sources of heterogeneity by incorporating city-specific characteristics.

RESULTS

The overall pooled estimation suggested a nonlinear exposure-response relationship between rainfall and HFMD. Once rainfall exceeded 15 mm, the HFMD risk stopped increasing linearly and began to plateau with the excessive risk ratio (ERR) peaking at 21 mm of rainfall (ERR = 3.46, 95% CI: 2.05, 4.88). We also found significant heterogeneity in the rainfall-HFMD relationships (I² = 52.75%, P < 0.001). By incorporating the city-specific characteristics into the meta-regression model, temperature and student density can explain a substantial proportion of spatial heterogeneity with I² statistics that decreased by 5.29 and 6.80% at most, respectively.

CONCLUSIONS

Our findings verified the nonlinear association between rainfall and HFMD. The rainfall-HFMD relationship also varies depending on locations. Therefore, the estimation of the rain-HFMD relationship of one location should not be generalized to another location.

Epidemiology of Hand, Foot, and Mouth Disease Before and After the Introduction of Enterovirus 71 Vaccines in Chengdu, China, 2009-2018

BACKGROUND

Hand, foot, and mouth disease (HFMD) has posed a serious threat to children's health. Three inactivated monovalent enterovirus 71 (EV71) vaccines are proved to be highly efficacious in phase III clinical trials and are now available in China.

METHODS

We analyzed the citywide surveillance data on HFMD cases in Chengdu during 2009-2018, and estimated cumulative first-dose EV71 vaccination coverage among children eligible to EV71 vaccination after August 2016 in Chengdu. Time series susceptible-infected-recovered model was developed to analyze basic reproduction number and herd immunity threshold of HFMD. Overall and serotype-specific HFMD incidences and severity risks were compared before and after the EV71 vaccination.

RESULTS

Among 3 laboratory-identified serotype categories, i.e. EV71, coxsackievirus A16 (CV-A16), and other enteroviruses, the major serotype attributed to HFMD has been changing across years. The cumulative first-dose EV71 vaccination coverage rate was estimated as 60.8% during the study period in Chengdu. By contrast, herd immunity threshold for EV71-related HFMD was 94.0%. After introduction of EV71 vaccines, the overall incidence of HFMD increased 60.8%, mainly driven by 173.7% and 11.8% increased in HFMD caused by other enteroviruses and CV-A16, respectively, which offset a significant reduction in the incidence of HFMD caused by EV71. The overall case-severity risk decreased from 1.4% to 0.3%, with significantly declined presented in all serotype categories.

CONCLUSIONS

The incidence and severity of EV71-related HFMD decreased following implementation of EV71 vaccination. Developing multivalent vaccines and strengthening laboratory-based surveillance could further decline burden of HFMD.

A marginal moment matching approach for fitting endemic-epidemic models to underreported disease surveillance counts

Count data are often subject to underreporting, especially in infectious disease surveillance. We propose an approximate maximum likelihood method to fit count time series models from the endemic-epidemic class to underreported data. The approach is based on marginal moment matching where underreported processes are approximated through completely observed processes from the same class. Moreover, the form of the bias when underreporting is ignored or taken into account via multiplication factors is analyzed. Notably, we show that this leads to a downward bias in model-based estimates of the effective reproductive number. A marginal moment matching approach can also be used to account for reporting intervals which are longer than the mean serial interval of a disease. The good performance of the proposed methodology is demonstrated in simulation studies. An extension to time-varying parameters and reporting probabilities is discussed and applied in a case study on weekly rotavirus gastroenteritis counts in Berlin, Germany.

Feasibility of containing shigellosis in Hubei Province, China: a modelling study

Background

The transmission features and the feasibility of containing shigellosis remain unclear among a population-based study in China.

Methods

A population–based Susceptible – Exposed – Infectious / Asymptomatic – Recovered (SEIAR) model was built including decreasing the infectious period (DIP) or isolation of shigellosis cases. We analyzed the distribution of the reported shigellosis cases in Hubei Province, China from January 2005 to December 2017, and divided the time series into several stages according to the heterogeneity of reported incidence during the period. In each stage, an epidemic season was selected for the modelling and assessing the effectiveness of DIP and case isolation.

Results

A total of 130,770 shigellosis cases were reported in Hubei Province. The median of R_eff was 1.13 (range: 0.86–1.21), 1.10 (range: 0.91–1.13), 1.09 (range: 0.92–1.92), and 1.03 (range: 0.94–1.22) in 2005–2006 season, 2010–2011 season, 2013–2014 season, and 2016–2017 season, respectively. The reported incidence decreased significantly (trend χ² = 8260.41, P <  0.001) among four stages. The incidence of shigellosis decreased sharply when DIP implemented in three scenarios (γ = 0.1, 0.1429, 0.3333) and when proportion of case isolation increased.

Conclusions

Year heterogeneity of reported shigellosis incidence exists in Hubei Province. It is feasible to contain the transmission by implementing DIP and case isolation.

Molecular characteristics of the VP1 region of enterovirus 71 strains in China

Background

Enterovirus 71 (EV71) is the most commonly implicated causative agent of severe outbreaks of paediatric hand, foot, and mouth disease (HFMD).VP1 protein, a capsid protein of EV71, is responsible for the genotype of the virus and is essential for vaccine development and effectiveness. However, the genotypes of EV71 isolates in China are still not completely clear.

Methods

The VP1 gene sequences of 3712 EV71 virus strains from China, excluding repetitive sequences and 30 known EV71 genotypes as reference strains, between 1986 and 2019 were obtained from GenBank. Phylogenetic tree, amino acid homology, genetic variation and genotype analyses of the EV71VP1 protein were performed with MEGA 6.0 software.

Results

The amino acid identity was found to be 88.33%–100% among the 3712 EV71 strains, 93.47%–100% compared with vaccine strain H07, and 93.04%–100% compared with vaccine strains FY7VP5 or FY-23 K-B. Since 2000, the prevalent strains of EV71 were mainly of the C4 genotype. Among these, the C4a subgenotype was predominant, followed by the C4b subgenotype; other subgenotypes appeared sporadically between 2005 and 2018 in mainland China. The B4 genotype was the main genotype in Taiwan, and the epidemic strains were constantly changing. Some amino acid variations in VP1 of EV71 occurred with high frequencies, including A289T (20.99%), H22Q (16.49%), A293S (15.95%), S283T (15.11%), V249I (7.76%), N31D (7.25%), and E98K (6.65%).

Conclusion

The C4 genotype of EV71 in China matches the vaccine and should effectively control EV71. However, the efficacy of the vaccine is partially affected by the continuous change in epidemic strains in Taiwan. These results suggest that the genetic characteristics of the EV71-VP1 region should be continuously monitored, which is critical for epidemic control and vaccine design to prevent EV71 infection in children.

Evaluation of the diagnostic performance and its associated factors of a commercial anti-EV-A71 IgM-capture ELISA kit in hospitalized children with clinical diagnostic HFMD

OBJECTIVES

Enterovirus A71 (EV-A71) is the main pathogen of severe hand, foot, and mouth disease (HFMD). Commercial enzyme-linked immunosorbent assays (ELISAs) are widely used in Chinese hospitals for the rapid diagnosis of acute EV-A71 infections. We present an evaluation of the diagnostic performance of a commercial anti-EV-A71 IgM-capture ELISA kit.

METHODS

A prospective, hospital-based HFMD cohort was established in Henan Children's Hospital (February 2017 - February 2018). Stool and blood specimens were collected from 1413 participants for diagnosing EVA71 by quantitative Real-Time Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) and anti-EV-A71 ELISA.

RESULTS

Detection yields of EV-A71 IgM increased from 6.5 % (95 % CI:3.3 %-11.4 %) at 0∼24 h, to 42 % (95 % CI:28.3 %-57.8) at 120∼144 h from onset to sampling, and stabilized at ∼40 % after 144 h. With increased time from onset to sampling, the sensitivity of the commercial ELISA increased from 0.54 (95 % CI:0.25-0.81) to 0.74 (95 % CI:0.43-0.66), while specificity decreased from 0.97 (95 % CI:0.93-0.99) to 0.80 (95 % CI:0.69-0.89), and PPV decreased from 0.96 (95 % CI:0.92-0.99) to 0.84 (95 % CI:0.73-0.92). Multivariate analysis found age, EV-A71 vaccination, previous HFMD/Herpangina infection, disease severity, infection during peak EV-A71 season, and sampling time after symptom onset were significantly associated with the diagnostic performance of this anti-EV-A71 IgM-capture ELISA.

CONCLUSION

Achieving satisfactory specificity and sensitivity scores, this commercial anti-EV-A71 IgM-capture ELISA kit is suitable for clinical EV-A71 diagnosis, particularly in resource-poor areas. However, clinicians should interpret results in the context of patient history and epidemiological setting.

Quantifying the risk of hand, foot, and mouth disease (HFMD) attributable to meteorological factors in East China: A time series modelling study

BACKGROUND

Hand, foot, and mouth disease (HFMD) is a widespread infectious disease in China. Associated meteorological factors have been widely studied, but their attributable risks have not been well quantified.

OBJECTIVES

The study aimed to quantify the HFMD burden attributable to temperature and other meteorological factors.

METHODS

The daily counts of HFMD and meteorological factors in all 574 counties of East China were obtained for the period from 2009 to 2015. The exposure-lag-response relationships between meteorological factors and HFMD were quantified by using a distributed lag non-linear model for each county and the estimates from all the counties were then pooled using a multivariate mete-regression model. Attributable risks were estimated for meteorological variables according to the exposure-lag-response relationships obtained before.

RESULTS

The study included 4,058,702 HFMD cases. Non-optimal values of meteorological factors were attributable to approximately one third of all HFMD cases, and the attributable numbers of non-optimal ambient temperature, relative humidity, wind speed and sunshine hours were 815,942 (95% CI: 796,361-835,888), 291,759 (95% CI: 226,183-358,494), 92,060 (95% CI: 59,655-124,738) and 62,948 (95% CI: 20,621-105,773), respectively. The exposure-response relationship between temperature and HFMD was non-linear with an approximate "M" shape. High temperature had a greater influence on HFMD than low temperature did. There was a geographical heterogeneity related to water body, and more cases occurred in days with moderate high and low temperatures than in days with extreme temperature. The effects of meteorological factors on HFMD were generally consistent across subgroups.

CONCLUSIONS

Non-optimal temperature is the leading risk factor of HFMD in East China, and moderate hot and moderate cold days had the highest risk. Developing subgroup-targeted and region-specific programs may minimize the adverse consequences of non-optimum weather on HFMD risk.

Seasonal Distribution and Meteorological Factors Associated with Hand, Foot, and Mouth Disease among Children in Xi'an, Northwestern China

Hand, foot, and mouth disease (HFMD) is a common infectious disease in the Asia-Pacific region that primarily affects children younger than 5 years. Previous studies have confirmed that the seasonal transmission of this disease is strongly related to meteorological factors, but the results are not consistent. In addition, the associations between weather conditions and HFMD in northwestern China have not been investigated. Therefore, we aimed to examine this issue in Xi'an, the largest city of northwestern China that has been suffering from serious HFMD epidemics. In the current study, data for HFMD and six meteorological factors were collected from 2009 to 2018. Using cross-correlation analysis, the Granger causality test, and the distributed lag nonlinear model, we estimated the quantitative relationships and exposure-lag-response effects between weekly meteorological factors and HFMD incidence among children. We found that the seasonal distribution of HFMD in Xi'an has two peaks each year and is significantly impacted by the weekly temperature, precipitation, and evaporation over an 8-week period. Higher values of temperature and evaporation had positive associations with disease transmission, whereas the association between precipitation and HFMD showed an inverted-U shape. The maximum relative risks (RRs) of HFMD for the weekly mean temperature (approximately 31.1°C), weekly cumulative evaporation (57.9 mm), and weekly cumulative precipitation (30.0 mm) were 1.56 (95% CI: 1.35-1.81), 1.40 (95% CI: 1.05-1.88), and 1.16 (95% CI: 1.11-1.70), respectively. The identified risk determinants and lag effects could provide important information for early interventions to reduce the local disease burden.

Integration of a Kalman filter in the geographically weighted regression for modeling the transmission of hand, foot and mouth disease

Background

Hand, foot and mouth disease (HFMD) is a common infectious disease whose mechanism of transmission continues to remain a puzzle for researchers. The measurement and prediction of the HFMD incidence can be combined to improve the estimation accuracy, and provide a novel perspective to explore the spatiotemporal patterns and determinant factors of an HFMD epidemic.

Methods

In this study, we collected weekly HFMD incidence reports for a total of 138 districts in Shandong province, China, from May 2008 to March 2009. A Kalman filter was integrated with geographically weighted regression (GWR) to estimate the HFMD incidence. Spatiotemporal variation characteristics were explored and potential risk regions were identified, along with quantitatively evaluating the influence of meteorological and socioeconomic factors on the HFMD incidence.

Results

The results showed that the average error covariance of the estimated HFMD incidence by district was reduced from 0.3841 to 0.1846 compared to the measured incidence, indicating an overall improvement of over 50% in error reduction. Furthermore, three specific categories of potential risk regions of HFMD epidemics in Shandong were identified by the filter processing, with manifest filtering oscillations in the initial, local and long-term periods, respectively. Amongst meteorological and socioeconomic factors, the temperature and number of hospital beds per capita, respectively, were recognized as the dominant determinants that influence HFMD incidence variation.

Conclusions

The estimation accuracy of the HFMD incidence can be significantly improved by integrating a Kalman filter with GWR and the integration is effective for exploring spatiotemporal patterns and determinants of an HFMD epidemic. Our findings could help establish more accurate HFMD prevention and control strategies in Shandong. The present study demonstrates a novel approach to exploring spatiotemporal patterns and determinant factors of HFMD epidemics, and it can be easily extended to other regions and other infectious diseases similar to HFMD.

Epidemiological characteristics and transmissibility of shigellosis in Hubei Province, China, 2005 - 2017

BACKGROUND

Shigellosis is one of the main diarrhea diseases in developing countries. However, the transmissibility of shigellosis remains unclear.

METHODS

We used the dataset of shigellosis cases reported between January 2005 and December 2017, from Hubei Province, China. A mathematical model was developed based on the natural history and the transmission mechanism of the disease. By fitting the data using the model, transmission relative rate from person to person (b) and from reservoir to person (bw), and the effective reproduction number (Reff) were estimated. To simulate the contribution of b and bw during the transmission, we performed a "knock-out" simulation in four scenarios: A) b = 0 and bw = 0; B) b = 0; C) bw = 0; D) control (no intervention).

RESULTS

A total of 130,770 shigellosis cases were reported in Hubei province, among which 13 cases were dead. The median annual incidence was 19.96 per 100,000 persons (range: 5.99 per 100,000 persons - 29.47 per 100,000 persons) with a decreased trend (trend χ2 = 25,470.27, P < 0.001). The mean values of b and bw were 0.0898 (95% confidence interval [CI]: 0.0851-0.0946) and 1.1264 × 10- 9 (95% CI: 4.1123 × 10- 10-1.8416 × 10- 9), respectively. The "knock-out" simulation showed that the number of cases simulated by scenario A was almost the same as scenario B, and scenario C was almost the same as scenario D. The mean value of Reff of shigellosis was 1.19 (95% CI: 1.13-1.25) and decreased slightly with a Linear model until it decreased to an epidemic threshold of 0.99 (95% CI: 0.65-1.34) in 2029.

CONCLUSIONS

The incidence of shigellosis is still in high level. The transmissibility of the disease is low in Hubei Province. The transmission would be interrupted in the year of 2029.

Transmission center and driving factors of hand, foot, and mouth disease in China: A combined analysis

Hand, foot, and mouth disease (HFMD) has become a major public health issue in China. The disease incidence varies substantially over time and across space. To understand the heterogeneity of HFMD transmission, we compare the spatiotemporal dynamics of HFMD in Qinghai and Shanghai by conducting combined analysis of epidemiological, wavelet time series, and mathematical methods to county-level data from 2009 to 2016. We observe hierarchical epidemic waves in Qinghai, emanating from Huangzhong and in Shanghai from Fengxian. Besides population, we also find that the traveling waves are significantly associated with socio-economic and geographical factors. The population mobility also varies between the two regions: long-distance movement in Qinghai and between-neighbor commuting in Shanghai. Our findings provide important evidence for characterizing the heterogeneity of HFMD transmission and for the design and implementation of interventions, such as deploying optimal vaccine and changing local driving factors in the transmission center, to prevent or limit disease spread in these areas.

Meteorological factors associated with hand, foot and mouth disease in a Central Highlands province in Viet Nam: an ecological study

Background

Hand, foot and mouth disease (HFMD) is a public health problem in Viet Nam, and studies have reported seasonal fluctuation in the occurrence of HFMD. This study sought to describe the occurrence of HFMD and its associated meteorological factors in Dak Lak province, Viet Nam.

Methods

Monthly data on HFMD cases were collected from all commune health stations in Dak Lak province from 2012 through 2013. An HFMD case was defined as a brief febrile illness accompanied by a typical skin rash with or without mouth ulcers. Average temperature, maximum temperature, minimum temperature, humidity, rainfall, evaporation, sunshine duration and wind speed were recorded monthly at five local meteorological stations throughout Dak Lak.Data were aggregated at the district level, and the association between these meteorological factors and HFMD cases were examined by Poisson regression.

Results

In 2012 through 2013, there were 7128 HFMD patients in Dak Lak. The number of HFMD cases increased during the rainy season. An increased risk of HFMD was associated with higher average temperature (risk ratio and 95% confidence interval: 1.06; 1.03-1.08 per 1 °C increase), higher rainfall (1.19; 1.14-1.24 per 200 mm increase) and longer sunshine duration (1.14; 1.07-1.22 per 60 hours increase). The risk of HFMD was inversely associated with wind speed (0.77; 0.73-0.81 per 1 m/s increase).

Conclusion

This study suggests that there is a significant association between HFMD occurrence and climate. Temperature, rainfall, wind speed and sunshine duration could be used as meteorological predictors of HFMD occurrence in Viet Nam's Central Highlands region. Intensified surveillance for HFMD during the rainy season is recommended.