Spatiotemporal variation of hand-foot-mouth disease in relation to socioecological factors: A multiple-province analysis in Vietnam

Spatiotemporal filtering modeling of hand, foot, and mouth disease: a case study from East China, 2009-2015

Hand, foot, and mouth disease (HFMD) shows spatiotemporal heterogeneity in China. A spatiotemporal filtering model was constructed and applied to HFMD data to explore the underlying spatiotemporal structure of the disease and determine the impact of different spatiotemporal weight matrices on the results. HFMD cases and covariate data in East China were collected between 2009 and 2015. The different spatiotemporal weight matrices formed by Rook, K-nearest neighbour (KNN; K = 1), distance, and second-order spatial weight matrices (SO-SWM) with first-order temporal weight matrices in contemporaneous and lagged forms were decomposed, and spatiotemporal filtering model was constructed by selecting eigenvectors according to MC and the AIC. We used MI, standard deviation of the regression coefficients, and five indices (AIC, BIC, DIC, R2, and MSE) to compare the spatiotemporal filtering model with a Bayesian spatiotemporal model. The eigenvectors effectively removed spatial correlation in the model residuals (Moran's I < 0.2, p > 0.05). The Bayesian spatiotemporal model's Rook weight matrix outperformed others. The spatiotemporal filtering model with SO-SWM was superior, as shown by lower AIC (92,029.60), BIC (92,681.20), and MSE (418,022.7) values, and higher R2 (0.56) value. All spatiotemporal contemporaneous structures outperformed the lagged structures. Additionally, eigenvector maps from the Rook and SO-SWM closely resembled incidence patterns of HFMD.

Air pollution's numerical, spatial, and temporal heterogeneous impacts on childhood hand, foot and mouth disease: a multi-model county-level study from China

BACKGROUND

While stationary links between childhood hand, foot and mouth disease (HFMD) and air pollution are known, a comprehensive study on their heterogeneous relationships (nonstationarity), jointly considering numerical, temporal and spatial dimensions, has not been reported.

METHODS

Monthly HFMD incidence and air pollution data were collected at the county level from Sichuan-Chongqing, China (2009-2011), alongside meteorological and social environmental covariates. Key influential factors were identified using random forest (RF) under the stationary assumption. Factors' numerically, temporally, and spatially heterogeneous relationships with HFMD were assessed using generalized additive model (GAM) and geographically and temporally weighted regression (GTWR).

RESULTS

Our findings highlighted the relatively higher stationary contributions of fine particulate matter (PM2.5) and ozone (O3) to HFMD incidence across Sichuan-Chongqing counties. We further uncovered heterogeneous impacts of PM2.5 and O3 from three nonstationary perspectives. Numerically, PM2.5 showed an inverse 'V'-shaped relationship with HFMD incidence, while O3 exhibited a complex pattern, with increased HFMD incidence at low PM2.5 and moderate O3 concentrations. Temporally, PM2.5's impact peaked in autumn and was weakest in spring, whereas O3's effect was strongest in summer. Spatially, hotspot mapping revealed high-risk clusters for PM2.5 impact across all seasons, with notable geographical variations, and for O3 in spring, summer, and autumn, concentrated in specific regions of Sichuan-Chongqing.

CONCLUSIONS

This study underscores the nuanced and three-perspective heterogeneous influences of air pollution on HFMD in small areas, emphasizing the need for differentiated, localized, and time-sensitive prevention and control strategies to enhance the precision of dynamic early warnings and predictive models for HFMD and other infectious diseases, particularly in the fields of environmental and spatial epidemiology.

The 2023 report of the MJA-Lancet Countdown on health and climate change: sustainability needed in Australia's health care sector

The MJA-Lancet Countdown on health and climate change in Australia was established in 2017 and produced its first national assessment in 2018 and annual updates in 2019, 2020, 2021 and 2022. It examines five broad domains: health hazards, exposures and impacts; adaptation, planning and resilience for health; mitigation actions and health co-benefits; economics and finance; and public and political engagement. In this, the sixth report of the MJA-Lancet Countdown, we track progress on an extensive suite of indicators across these five domains, accessing and presenting the latest data and further refining and developing our analyses. Our results highlight the health and economic costs of inaction on health and climate change. A series of major flood events across the four eastern states of Australia in 2022 was the main contributor to insured losses from climate-related catastrophes of $7.168 billion - the highest amount on record. The floods also directly caused 23 deaths and resulted in the displacement of tens of thousands of people. High red meat and processed meat consumption and insufficient consumption of fruit and vegetables accounted for about half of the 87 166 diet-related deaths in Australia in 2021. Correction of this imbalance would both save lives and reduce the heavy carbon footprint associated with meat production. We find signs of progress on health and climate change. Importantly, the Australian Government released Australia's first National Health and Climate Strategy, and the Government of Western Australia is preparing a Health Sector Adaptation Plan. We also find increasing action on, and engagement with, health and climate change at a community level, with the number of electric vehicle sales almost doubling in 2022 compared with 2021, and with a 65% increase in coverage of health and climate change in the media in 2022 compared with 2021. Overall, the urgency of substantial enhancements in Australia's mitigation and adaptation responses to the enormous health and climate change challenge cannot be overstated. Australia's energy system, and its health care sector, currently emit an unreasonable and unjust proportion of greenhouse gases into the atmosphere. As the Lancet Countdown enters its second and most critical phase in the leadup to 2030, the depth and breadth of our assessment of health and climate change will be augmented to increasingly examine Australia in its regional context, and to better measure and track key issues in Australia such as mental health and Aboriginal and Torres Strait Islander health and wellbeing.

Climate change and human health in Vietnam: a systematic review and additional analyses on current impacts, future risk, and adaptation

This study aims to investigate climate change's impact on health and adaptation in Vietnam through a systematic review and additional analyses of heat exposure, heat vulnerability, awareness and engagement, and projected health costs. Out of 127 reviewed studies, findings indicated the wider spread of infectious diseases, and increased mortality and hospitalisation risks associated with extreme heat, droughts, and floods. However, there are few studies addressing health cost, awareness, engagement, adaptation, and policy. Additional analyses showed rising heatwave exposure across Vietnam and global above-average vulnerability to heat. By 2050, climate change is projected to cost up to USD1-3B in healthcare costs, USD3-20B in premature deaths, and USD6-23B in work loss. Despite increased media focus on climate and health, a gap between public and government publications highlighted the need for more governmental engagement. Vietnam's climate policies have faced implementation challenges, including top-down approaches, lack of cooperation, low adaptive capacity, and limited resources.

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.

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.

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.

Forecast and early warning of hand, foot, and mouth disease based on meteorological factors: Evidence from a multicity study of 11 meteorological geographical divisions in mainland China

BACKGROUND

Hand, foot, and mouth disease (HFMD) is a significant public health issue in China. Early warning and forecasting are one of the most cost-effective ways for HFMD control and prevention. However, relevant research is limited, especially in China with a large population and diverse climatic characteristics. This study aims to identify local specific HFMD epidemic thresholds and construct a weather-based early warning model for HFMD control and prevention across China.

METHODS

Monthly notified HFMD cases and meteorological data for 22 cities selected from different climate zones from 2014 to 2018 were extracted from the National Notifiable Disease Surveillance System and the Meteorological Data Sharing Service System, respectively. A generalized additive model (GAM) based on meteorological factors was conducted to forecast HFMD epidemics. The receiver operator characteristic curve (ROC) was generated to determine the value of optimal warning threshold.

RESULTS

The developed model was solid in forecasting the epidemic of HFMD with all R square (R²) in the 22 cities above 85%, and mean absolute percentage error (MAPE) less than 1%. The warning thresholds varied by cities with the highest threshold observed in Shenzhen (n = 7195) and the lowest threshold in Liaoyang (n = 12). The areas under the curve (AUC) was greater than 0.9 for all regions, indicating a satisfied discriminating ability in epidemics detection.

CONCLUSIONS

The weather-based HFMD forecasting and early warning model we developed for different climate zones provides needed information on occurrence time and size of HFMD epidemics. An effective early warning system for HFMD could provide sufficient time for local authorities to implement timely interventions to minimize the HFMD morbidity and mortality.

Nonlinear effect of temperature on hand, foot, and mouth disease in Lanzhou, China

To examine the effects of temperature on the daily cases of hand, foot, and mouth disease (HFMD).Data on the daily cases of HFMD in Lanzhou from 2008 to 2015 were obtained, and meteorological data from the same period were collected. A distributed lag nonlinear model was fitted to reveal the relationship between the daily mean temperature and the daily cases of HFMD.From 2008 to 2015, 25,644 cases were reported, of which children under 5 years of age accounted for 78.68% of cases. The highest peak of HFMD cases was usually reported between April to July each year. An inverse V-shaped relationship was observed between daily mean temperature and HFMD cases; a temperature of 18°C was associated with a maximum risk of HFMD. The relative risk (RR) was 1.57 (95% confidence interval: 1.23-1.23), and boys and children aged 3 to 5 years were populations with the highest risk. The cumulative risks of high temperature (20.2°C and 25.2°C) in the total, age-specific, and gender-specific groups peaked on lag 14 days; RR was higher in girls than in boys and in children aged 1 to 2 years than in other age groups. However, the effects of low temperature (-5.3°C, 2.0°C, and 12.8°C) were not significant for both gender-specific and age-specific patients.High temperature may increase the risk of HFMD, and boys and children aged 3 to 5 years were at higher risks on lag 0 day; however, the cumulative risks in girls and children aged 1 to 2 years increased with the increasing number of lag days.

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.

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.

Temporal relationships between climate variables and hand-foot-mouth disease: a multi-province study in the Mekong Delta Region, Vietnam

Hand-foot-mouth disease (HFMD) is an emerging infectious disease that affects thousands of children every year in Vietnam, especially in the Mekong Delta Region (MDR). This study aims to analyse both provincial and regional level effects of climate factors on HFMD in multiple provinces of this high-risk region. Generalized linear models were used to analyse the daily effects of average temperature, humidity and rainfall on HFMD incidence in each province (provincial-level effects), and random-effect meta-analysis was used to estimate the pooled effect size of these climate-HFMD associations (regional-level effects). Daily effects of the climate factors on HFMD were found at both provincial level and regional level. At provincial level, temperature and humidity had statistically significant positive associations with HFMD while rainfall had both positive and negative associations with HFMD at different lag days. At regional level, temperature and humidity were positively associated with HFMD at lag 0 days (1.7%; 95%CI 0.1%-3.3%) and at lag 3 days (0.3%; 95%CI 0.1%-0.5%), respectively. In contrast, rainfall was found to be negatively associated with HFMD at lag 5 days (- 0.3%; 95%CI - 0.4% to - 0.1%). Heterogeneities of the effects of rainfall on HFMD were found to be higher than those of temperature or humidity. This is the first study to address the climate-HFMD associations in multiple provinces of the MDR. These associations draw attention to climate-related health issues and will help in developing an environment-based early warning system for HFMD prevention and control.

Spatial-temporal variation and risk factor analysis of hand, foot, and mouth disease in children under 5 years old in Guangxi, China

BACKGROUND

Hand, foot and mouth disease (HFMD) incidence is a critical challenge to disease control and prevention in parts of China, particularly Guangxi. However, the association between socioeconomic factors and meteorological factors on HFMD is still unclear.

METHODS

This study applied global and local Moran's I to examine the spatial pattern of HFMD and series analysis to explore the temporal pattern. The effects of meteorological factors and socioeconomic factors on HFMD incidence in Guangxi, China were analyzed using GeoDetector Model.

RESULTS

This study collected 45,522 cases from 87 counties in Guangxi during 2015, among which 43,711 cases were children aged 0-4 years. Temporally, there were two HFMD risk peaks in 2015. One peak was in September with 7890 cases. The other appeared in May with 4687 cases of HFMD. A high-risk cluster was located in the valley areas. The tertiary industry, precipitation and second industry had more influence than other risk factors on HFMD incidence with explanatory powers of 0.24, 0.23 and 0.21, respectively. The interactive effect of any two risk factors would enhance the risk of HFMD.

CONCLUSIONS

This study suggests that precipitation and tertiary industry factors might have stronger effects on the HFMD incidence in Guangxi, China, compared with other factors. High-risk of HFMD was identified in the valley areas characterized by high temperature and humidity. Local government should pay more attention and strengthen public health services level in this area.

Short-Term Effects of Meteorological Factors and Air Pollutants on Hand, Foot and Mouth Disease among Children in Shenzhen, China, 2009-2017

BACKGROUND

A few studies have explored the association between meteorological factors and hand, foot, and mouth disease (HFMD) with inconsistent results. Besides, studies about the effects of air pollutants on HFMD are very limited.

METHODS

Daily HFMD cases among children aged 0-14 years in Shenzhen were collected from 2009 to 2017. A distributed lag nonlinear model (DLNM) model was fitted to simultaneously assess the nonlinear and lagged effects of meteorological factors and air pollutants on HFMD incidence, and to further examine the differences of the effect across different subgroups stratified by gender, age and childcare patterns.

RESULTS

The cumulative relative risk (cRR) (median as reference) of HFMD rose with the increase of daily temperature and leveled off at about 30 °C (cRR: 1.40, 95%CI: 1.29, 1.51). There was a facilitating effect on HFMD when relative humidity was 46.0% to 88.8% (cRR at 95th percentile: 1.18, 95%CI: 1.11, 1.27). Short daily sunshine duration (5th vs. 50th) promoted HFMD (cRR: 1.07, 95%CI: 1.02, 1.11). The positive correlation between rainfall and HFMD reversed when it exceeded 78.3 mm (cRR: 1.41, 95% CI: 1.22, 1.63). Ozone suppressed HFMD when it exceeded 104 µg /m3 (cRR at 99th percentile: 0.85, 95%CI: 0.76, 0.94). NO₂ promoted HFMD among infants and the cRR peaked at lag 9 day (cRR: 1.47, 95%CI: 1.02, 2.13) (99th vs. 50th). Besides, children aged below one year, males and scattered children were more vulnerable to high temperature, high relative humidity, and short sunshine duration.

CONCLUSIONS

Temperature, relative humidity, sunshine duration, rainfall, ozone and NO₂ were significantly associated with HFMD, and such effects varied with gender age and childcare patterns. These findings highlight the need for more prevention effort to the vulnerable populations and may be helpful for developing an early environment-based warning system for HFMD.

Estimating the transmissibility of hand, foot, and mouth disease by a dynamic model

OBJECTIVE

Hand, foot, and mouth disease (HFMD) is a serious public health issue in many countries; however, its transmissibility in county-level outbreaks remains unclear. The aim of this study is to estimate the transmissibility of HFMD epidemics on both city level and county level, for a better understanding of the transmission dynamics of HFMD epidemics.

STUDY DESIGN

Simulation based on data obtained from the China Information System for Disease Control and Prevention.

METHODS

The weekly number of reported HFMD cases from April 2009 to December 2017 in nine regions of Changsha City was collected. A susceptible-infectious-recovered model was used to estimate the transmissibility of HFMD. The reproduction number of reported cases during the ascending (denoted as R_asc) and descending (denoted as R_des) period was used to describe the transmissibility of HFMD.

RESULTS

The R_asc and R_des for HFMD in Changsha was 1.44 (95% confidence interval [CI]: 1.41-1.48) and 0.71 (95% CI: 0.69-0.73), respectively. There was no statistical significance of R_asc values among nine regions (F = 1.056, P = 0.396), nor of R_des values among nine regions (F = 1.676, P = 0.106). The average R_asc (1.53, 95% CI: 1.46-1.61) from 2009 to 2012 was higher than the one (1.37, 95% CI: 1.34-1.40) from 2013 to 2017 (t = 3.974, P < 0.001), but the average R_des (0.67, 95% CI: 0.63-0.70) from 2009 to 2012 was lower than the one (0.74, 95% CI: 0.73-0.76) from 2013 to 2017 (t = -3.751, P < 0.001).

CONCLUSIONS

The epidemic of HFMD in Changsha City is still grim, and integrated strategies should be taken for controlling and preventing HFMD.

A spatial-temporal statistical analysis of health seasonality: explaining HFMD infections within a children population along the Vietnamese south central coast

Background

Various neglected tropical diseases show spatially changing seasonality at small areas. This phenomenon has received little scientific attention so far. Our study contributes to advancing the understanding of its drivers. This study focuses on the effects of the seasonality of increasing social contacts on the incidence proportions at multiple district level of the childhood hand-foot-mouth disease in Da Nang city, Viet Nam from 2012 to 2016.

Methods

We decomposed the nonstationary time series of the incidence proportions for the nine spatial-temporal (S-T) strata in the study area, where S indicates the spatial and T the temporal stratum. The long-term trends and the seasonality are presented by the Fourier series. To study the effects of the monthly average ambient temperature and the period of preschooling, we developed a spatial-temporal autoregressive model.

Results

Seasonality of childhood hand-foot-mouth disease incidence proportions shows two peaks in all spatial strata annually: large peaks synchronously in April and small ones asynchronously during the preschooling period. The peaks of the average temperature are asynchronous with the seasonal peaks of the childhood hand-foot-mouth disease incidence proportions in the period between January and May, with the negative values of the regression coefficients for all spatial strata, respectively: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\beta}_{{\mathrm{T}}_11}^{S_1}=-0.18\pm 0.07;{\beta}_{{\mathrm{T}}_11}^{S_2}=-0.25\pm 0.09;{\beta}_{{\mathrm{T}}_11}^{S_3}=-0.14\pm 0.05 $$\end{document}βT11S1=−0.18±0.07;βT11S2=−0.25±0.09;βT11S3=−0.14±0.05. The increasingly cumulative preschooling period and the seasonal component of the incidence proportions are negatively correlated in the period between August and December, with the negative values of the regression coefficients for all temporal strata, respectively: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\beta}_{{\mathrm{T}}_32}^{S_1}=-0.40\pm 0.01;{\beta}_{{\mathrm{T}}_32}^{S_2}=-0.29\pm 0.00;{\beta}_{{\mathrm{T}}_32}^{S_3}=-0.25\pm 0.01 $$\end{document}βT32S1=−0.40±0.01;βT32S2=−0.29±0.00;βT32S3=−0.25±0.01.

Conclusions

The study shows that social contact amongst children under five years of age is the important driving factor of the dynamics of the childhood hand-foot-mouth disease outbreaks in the study area. The preschooling season when children’s contact with each other increases stimulates the geographical variation of the seasonality of childhood hand-foot-mouth disease infections at small areas in the study area.

Spatiotemporal Distribution of Hand, Foot, and Mouth Disease in Guangdong Province, China and Potential Predictors, 2009⁻2012

Background: Hand, foot, and mouth disease (HFMD) is a common infectious disease among children. Guangdong Province is one of the most severely affected provinces in south China. This study aims to identify the spatiotemporal distribution characteristics and potential predictors of HFMD in Guangdong Province and provide a theoretical basis for the disease control and prevention. Methods: Case-based HFMD surveillance data from 2009 to 2012 was obtained from the China Center for Disease Control and Prevention (China CDC). The Bayesian spatiotemporal model was used to evaluate the spatiotemporal variations of HFMD and identify the potential association with meteorological and socioeconomic factors. Results: Spatially, areas with higher relative risk (RR) of HFMD tended to be clustered around the Pearl River Delta region (the mid-east of the province). Temporally, we observed that the risk of HFMD peaked from April to July and October to December each year and detected an upward trend between 2009 and 2012. There was positive nonlinear enhancement between spatial and temporal effects, and the distribution of relative risk in space was not fixed, which had an irregular fluctuating trend in each month. The risk of HFMD was significantly associated with monthly average relative humidity (RR: 1.015, 95% CI: 1.006–1.024), monthly average temperature (RR: 1.045, 95% CI: 1.021–1.069), and monthly average rainfall (RR: 1.004, 95% CI: 1.001–1.008), but not significantly associated with average GDP. Conclusions: The risk of HFMD in Guangdong showed significant spatiotemporal heterogeneity. There was spatiotemporal interaction in the relative risk of HFMD. Adding a spatiotemporal interaction term could well explain the change of spatial effect with time, thus increasing the goodness of fit of the model. Meteorological factors, such as monthly average relative humidity, monthly average temperature, and monthly average rainfall, might be the driving factors of HFMD.

Priority focus areas for a sub-national response to climate change and health: A South African provincial case study

INTRODUCTION

The intersection of health and climate change is often absent or under-represented in sub-national government strategies. This analysis of the literature, using a new methodological framework, highlights priority focus areas for a sub-national government response to health and climate change, using the Western Cape (WC) province of South Africa as a case study.

METHODS

A methodological framework was created to conduct a review of priority focus areas relevant for sub-national governments. The framework encompassed the establishment of a Project Steering Group consisting of relevant, sub-national stakeholders (e.g. provincial officials, public and environmental health specialists and academics); an analysis of local climatic projections as well as an analysis of global, national and sub-national health risk factors and impacts.

RESULTS

Globally, the discussion of health and climate change adaptation strategies in sub-national, or provincial government is often limited. For the case study presented, multiple health risk factors were identified. WC climatic projections include a warmer and potentially drier future with an increased frequency and intensity of extreme weather events. WC government priority focus areas requiring further research on health risk factors include: population migration and environmental refugees, land use change, violence and human conflict and vulnerable groups. WC government priority focus areas for further research on health impacts include: mental ill-health, non-communicable diseases, injuries, poisonings (e.g. pesticides), food and nutrition insecurity-related diseases, water- and food-borne diseases and reproductive health. These areas are currently under-addressed, or not addressed at all, in the current provincial climate change strategy.

CONCLUSIONS

Sub-national government adaptation strategies often display limited discussion on the health and climate change intersect. The methodological framework presented in this case study can be globally utilized by other sub-national governments for decision-making and development of climate change and health adaptation strategies. Additionally, due to the broad range of sectoral issues identified, a primary recommendation from this study is that sub-national governments internationally should consider a "health and climate change in all policies" approach when developing adaptation and mitigation strategies to address climate change.

Space-time heterogeneity of hand, foot and mouth disease in children and its potential driving factors in Henan, China

BACKGROUND

Hand, foot and mouth disease (HFMD) has become a substantial threat recently. However few studies have quantified spatiotemporal heterogeneity of HFMD and detected spatiotemporal interactive effect of potential driving factors on this disease.

METHODS

Using GeoDetector and Bayesian space-time hierarchy model, we characterized the epidemiology of HFMD in Henan, one of the largest population provinces in China, from 2012 to 2013, and quantified the impacts of potential driving factors.

RESULTS

Notably, 21.43 and 24.60% counties were identified as hot and cold spots, respectively. Spatially, the hotspots were mainly clustered in regions where the economic level was high. Temporally, the highest incidence period of HFMD was discovered to be in late spring and early summer. The impact of meteorological and socio-economic factors on the disease are significant, and this study found that a 1 °C rise in temperature was related to an increase of 4.09% in the HFMD incidence, a 1% increment in relative humidity was associated with a 1.77% increase of the disease, and a 1% increment in ratio of urban to rural population was associated with a 0.16% increase of the disease.

CONCLUSION

Meteorological and socio-economic factors presented significantly association with HFMD incidence, high-risk mainly appeared in large cities and their adjacent regions in hot and humid season. These findings will be helpful for HFMD risk control and disease-prevention policies implementation.

Molecular epidemiology and clinical features of hand, foot and mouth disease in northern Thailand in 2016: a prospective cohort study

Background

Hand, foot and mouth disease (HFMD) is a major communicable disease in children ≤6 years old, particularly in several countries in the Asia-Pacific Region, including Thailand. HFMD impacts public health and the economy, especially in northern Thailand.

Methods

A prospective cohort study was conducted to estimate the incidence rate and to identify the serotype and clinical features of HFMD among children in northern Thailand. A validated questionnaire and throat swab were used for data collection. Polymerase chain reaction (PCR) was used to detect human enterovirus and identify its serotypes. Participants were recruited from 14 hospitals in two provinces in northern Thailand, specifically, Chiang Rai and Pha Yao Province, between January 1, 2016, and December 31, 2016. Chi-square or Fisher’s exact test was used to detect the associations of signs and symptoms with HFMD serotype. Logistic regression was used to detect the associations of variables with a positive enterovirus at alpha = 0.05.

Result

In total, 612 children aged ≤6 years from Chiang Rai and Pha Yao Province who were diagnosed with HFMD by a throat swab were recruited for the analysis. Approximately half of the cohort was male (57.2%), 57.5% was aged < 2 years, and 57.5% lived in rural areas. The incidence rate was 279.72/100,000 person-years in Chiang Rai Province and 321.24 per 100,000 person-years in Pha Yao Province. Additionally, 42.5% of children were positive for human enterovirus; among these children, 56.1% were positive for enterovirus-A (EV-A), 17.7% were positive for coxsackievirus (CV), and 26.2% were positive for other human RNA enteroviruses. During the study period, 21 distinct outbreaks of HFMD were recognized. Four to five patients (total 92 patients) were selected from each outbreak for identifying its serotype; enterovirus-A71 (EV-A71) was detected in 34.8% of HFMD cases, coxsackievirus-A16 (CV-A16) in 26.1%, coxsackivirus-A6 (CV-A6) in 15.2%, coxsackievirus-A10 (CV-A10) in 10.9%, coxsackievirus-A4 (CV-A4) in 2.2%, coxsackievirus-B2 (CV-B2) in 2.2%, human rhinovirus in 2.2%, and unknown serotype in 6.4%. Multivariable analysis demonstrated that a history of breastfeeding for ≤6 months was associated with a higher chance of enterovirus infection than a history of breastfeeding > 6 months, and children who had mother who worked as farmers, daily wage employees, and unprofessional skilled jobs had a greater chance of enterovirus infection than those who had unemployed mothers. Coxsackievirus-infected children had a higher rate of rashes on the buttocks, knee, and elbow and fever but a lower rate of lethargy and malaise than EV-A71-infected children.

Conclusions

EV-A71 is a major cause of HFMD in children < 6 years old in northern Thailand, but rash, fever, and mouth ulcers are mostly found in participants with coxsackievirus infection. Breastfeeding should be promoted during early childhood for at least 6 months to prevent HFMD particularly those mother who are working in unprofessional skill jobs.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3560-4) contains supplementary material, which is available to authorized users.

Temperature and humidity affect the incidence of hand, foot, and mouth disease: a systematic review of the literature - a report from the International Society of Dermatology Climate Change Committee

Hand, foot, and mouth disease (HFMD) is an enterovirus-mediated condition that predominantly affects children under 5 years of age. The tendency for outbreaks to peak in warmer summer months suggests a relationship between HFMD and weather patterns. We reviewed the English-language literature for articles describing a relationship between meteorological variables and HFMD. Seventy-two studies meeting criteria were identified. A positive, statistically significant relationship was identified between HFMD cases and both temperature (61 of 67 studies, or 91.0%, reported a positive relationship) [CI 81.8-95.8%, P = 0.0001] and relative humidity (41 of 54 studies, or 75.9%) [CI 63.1-85.4%, P = 0.0001]. No significant relationship was identified between HFMD and precipitation, wind speed, and/or sunshine. Most countries reported a single peak of disease each year (most commonly early Summer), but subtropical and tropical climate zones were significantly more likely to experience a bimodal distribution of cases throughout the year (two peaks a year; most commonly late spring/early summer, with a smaller peak in autumn). The rising global incidence of HFMD, particularly in Pacific Asia, may be related to climate change. Weather forecasting might be used effectively in the future to indicate the risk of HFMD outbreaks and the need for targeted public health interventions.

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.

Ambient temperature, humidity and hand, foot, and mouth disease: A systematic review and meta-analysis

BACKGROUND

The relationship between ambient temperature, humidity and hand, foot, and mouth disease (HFMD) has been highlighted in East and Southeast Asia, which showed multiple different results. Therefore, our goal is to conduct a meta-analysis to further clarify this relationship and to quantify the size of these effects as well as the susceptible populations.

METHODS

PubMed, Web of science, and Cochrane library were searched up to November 22, 2017 for articles analyzing the relationships between ambient temperature, humidity and incidence of HFMD. We assessed sources of heterogeneity by study design (temperature measure and exposed time resolution), population vulnerability (national income level and regional climate) and evaluated pooled effect estimates for the subgroups identified in the heterogeneity analysis.

RESULTS

We identified 11 studies with 19 estimates of the relationship between ambient temperature, humidity and incidence of HFMD. It was found that per 1°C increase in the temperature and per 1% increase in the relative humidity were both significantly associated with increased incidence of HFMD (temperature: IRR, 1.05; 95% CI, 1.02-1.08; relative humidity: IRR, 1.01; 95% CI, 1.00-1.02). Subgroup analysis showed that people living in subtropical and middle income areas had a higher risk of incidence of HFMD.

CONCLUSIONS

Ambient temperature and humidity may increase the incidence of HFMD in Asia-Pacific regions. Further studies are needed to clarify the relationship between ambient temperature, humidity and incidence of HFMD in various settings with distinct climate, socioeconomic, and demographic features.

The effects of socioecological factors on variation of communicable diseases: A multiple-disease study at the national scale of Vietnam

OBJECTIVE

To examine the effects of socioecological factors on multiple communicable diseases across Vietnam.

METHODS

We used the Moran's I tests to evaluate spatial clusters of diseases and applied multilevel negative binomial regression models using the Bayesian framework to analyse the association between socioecological factors and the diseases queried by oral, airborne, vector-borne, and animal transmission diseases.

RESULTS AND SIGNIFICANCE

The study found that oral-transmission diseases were spatially distributed across the country; whereas, the airborne-transmission diseases were more clustered in the Northwest and vector-borne transmission diseases were more clustered in the South. Most of diseases were sensitive with climatic factors. For instance, a 1°C increase in average temperature is significantly associated with 0.4% (95CI, 0.3-0.5), 2.5% (95%CI, 1.4-3.6), 0.9% (95%CI, 0.6-1.4), 1.1% (95%CI), 5% (95%CI, 3-.7.4), 0.4% (95%CI, 0.2-0.7), and 2% (95%CI, 1.5-2.8) increase in risk of diarrhoea, shigellosis, mumps, influenza, dengue, malaria, and rabies respectively. The influences of socio-economic factors on risk of communicable diseases are varied by factors with the biggest influence of population density. The research findings reflect an important implication for the climate change adaptation strategies of health sectors. A development of weather-based early warning systems should be considered to strengthen communicable disease prevention in Vietnam.