Epidemiology of hand, foot, and mouth disease in children in Shanghai 2007–2010

Modification effects of long-term air pollution levels on the relationship between short-term exposure to meteorological factors and hand, foot, and mouth disease: A distributed lag non-linear model-based study in Shandong Province, China

The occurrence of hand, foot, and mouth disease (HFMD) is closely related to meteorological factors. However, location-specific characteristics, such as persistent air pollution, may increase the complexity of the impact of meteorological factors on HFMD, and studies across different areas and populations are largely lacking. In this study, a two-stage multisite time-series analysis was conducted using data from 16 cities in Shandong Province from 2015 to 2019. In the first stage, we obtained the cumulative exposure-response curves of meteorological factors and the number of HFMD cases for each city. In the second stage, we merged the estimations from the first stage and included city-specific air pollution variables to identify significant effect modifiers and how they modified the short-term relationship between HFMD and meteorological factors. High concentrations of air pollutants may reduce the risk effects of high average temperature on HFMD and lead to a distinct peak in the cumulative exposure-response curve, while lower concentrations may increase the risk effects of high relative humidity. Furthermore, the effects of average wind speed on HFMD were different at different levels of air pollution. The differences in modification effects between subgroups were mainly manifested in the diversity and quantity of significant modifiers. The modification effects of long-term air pollution levels on the relationship between sunshine hours and HFMD may vary significantly depending on geographical location. The people in age＜3 and male groups were more susceptible to long-term air pollution. These findings contribute to a deepening understanding of the relationship between meteorological factors and HFMD and provide evidence for relevant public health decision-making.

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.

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.

Population based hospitalization burden of laboratory-confirmed hand, foot and mouth disease caused by multiple enterovirus serotypes in Southern China

BACKGROUND

Hand, foot and mouth disease (HFMD) is spread widely across Asia, and the hospitalization burden is currently not well understood. Here, we estimated serotype-specific and age-specific hospitalization rates of HFMD in Southern China.

METHODS

We enrolled pediatric HFMD patients admitted to 3/3 county-level hospitals, and 3/23 township-level hospitals in Anhua county, Hunan (CN). Samples were collected to identify enterovirus serotypes by RT-PCRs between October 2013 and September 2016. Information on other eligible, but un-enrolled, patients were retrospectively collected from the same six hospitals. Monthly numbers of all-cause hospitalizations were collected from each of the 23 township-level hospitals to extrapolate hospitalizations associated with HFMD among these.

RESULTS

During the three years, an estimated 3,236 pediatric patients were hospitalized with lab-confirmed HFMD, and among these only one case was severe. The mean hospitalization rate was 660 (95% CI: 638-684) per 100,000 person-years for lab-confirmed HFMD, with higher rates among CV-A16 and CV-A6 associated HFMD (213 vs 209 per 100,000 person-years), and lower among EV-A71, CV-A10 and other enterovirus associated HFMD (134, 39 and 66 per 100,000 person-years respectively, p<0.001). Children aged 12-23 months had the highest hospitalization rates (3,594/100,000 person-years), followed by those aged 24-35 months (1,828/100,000 person-years) and 6-11 months (1,572/100,000 person-years). Compared with other serotypes, CV-A6-associated hospitalizations were evident at younger ages.

CONCLUSIONS

Our study indicates a substantial hospitalization burden associated with non-severe HFMD in a rural county in southern China. Future mitigation policies should take into account the disease burden identified, and optimize interventions for HFMD.

Reinfection hazard of hand-foot-mouth disease in Wuhan, China, using Cox-proportional hazard model

Hand-foot-mouth disease (HFMD) is an acute infectious disease caused by serotypes of the enterovirus (EV) family. HFMD reinfection occurs commonly in lack of cross-protection between different EV serotypes. In this study, we investigated the hazards of HFMD reinfection using Cox-proportional hazard model. Retrospective data of 95 209 HFMD cases in Wuhan during 2008-2015 was used. Kaplan-Meier survival methods and Cox-proportional hazard model were used to estimate the hazard probabilities. Of the all HFMD cases, about 2% experienced reinfection (1842/95 209). Kaplan-Meier curves revealed the reinfection risk sharply increased before 40 months from first infection. Higher hazards of reinfection were detected among those who were males, aged 3 years and below, scattered children, belonging to urban areas and first infected with coxsackievirus (CV)-A16 compared with their respective counterparts. Cox-proportional hazard model suggested that gender, age, group, living area and serotypes of first infection had significant effect on reinfection even after adjusting for potential confounding effects of other selected factors considered in the study. These results indicate that boys aged 3 years and below, especially those living in urban areas and first infected with CV-A16 are more prone to reinfection. Interventions should be imposed on these high-risk populations.

Epidemiological surveillance of hand, foot and mouth disease in Shanghai in 2014-2016, prior to the introduction of the enterovirus 71 vaccine

Hand, foot, and mouth disease (HFMD) is mainly epidemic in China and Southeast Asian countries. A novel enterovirus 71 vaccine has been available in China for preventing severe HFMD since 2016. Knowledge of the dynamic epidemiology of HFMD in different regions is necessary for appropriate intervention strategies. This study focused on the citywide surveillance data on the epidemiology and etiology of HFMD in Shanghai during 2014–2016. In these 3 years, the total numbers of reported HFMD cases were 65,018, 39,702, and 57,548, respectively; the numbers of severe cases (case-severity ratios) were 248 (0.38%), 35 (0.09%), and 59 (0.10%), respectively. Children <6 years old accounted for 86.65% to 89.34% of HFMD cases and 91.53 to 97.14% of severe cases. EV-A71 caused all three fatal cases. In severe cases, the detection rate of EV-A71 was 77.82% in 2014, 100% in 2015 and 98.31% in 2016. In uncomplicated inpatient cases, the detection rates of EV-A71, CV-A16, CV-A6, and CV-A10 were, respectively, 43.40, 22.10, 30.73, and 1.89% in 2014; 28.52, 6.46, 53.61, and 7.98% in 2015; and 31.79, 14.15, 44.55, and 4.64% in 2016. In mild community cases, the detection rates of EV-A71, CV-A16, CV-A6, and CV-A10 were, respectively, 25.78, 41.64, 22.93, and 1.78% in 2014; 17.41, 21.23, 50.99, and 3.15% in 2015; and 18.92, 27.84, 45.11, and 1.64% in 2016. Among the cluster outbreaks, the most common pathogen was CV-A16 in 2014 (50.69%) and 2015 (38.10%) and CV-A6 in 2016 (36.30%). These findings show that HFMD outbreaks remained at a high level in Shanghai during 2014–2016. CV-A6 was emerging as the most common pathogen causing HFMD.

Prognostic Value of B-Type Natriuretic Peptide, Leukocytosis, and Hyperglycemia in Children with Severe Hand, Foot, and Mouth Disease

OBJECTIVE

Our goal is to determine the prognostic value of serum N-terminal prohormone of brain natriuretic peptide (NT-proBNP), leukocytosis, and hyperglycemia in patients with severe hand, foot, and mouth disease (HFMD).

DESIGN

This is a prospective cohort study conducted from March 2011 through October 2012 at Hunan Children's Hospital.

SETTING

Hunan Children's Hospital, a large children's teaching hospital with 1,500-beds located in the Changsha region of Hunan Province in China.

PATIENTS

295 children who were presented with clinical manifestation of severe HFMD, and required hospitalization.

INTERVENTIONS

Standard supportive treatment for HFMD as recommended by the national guidelines.

MEASUREMENTS

Admission blood samples were analyzed for NT-proBNP, leukocyte count, and serum glucose. Independent prognostic value of NT-proBNP for predicting mortality was evaluated using the Cox proportional hazard model adjusting for various covariates.

MAIN RESULTS

Area under the curve of receiver operating characteristic (AUROC) analysis suggested that a serum concentration of NT-proBNP concentration more than 1,500 pg/mL is an optimal cutoff point. Twenty-four patients (8.1%) had an NT-proBNP more than 1,500 pg/mL, and a 3-day mortality of 46% (11/24). Adjusted for tachycardia, tachypnea, hypertension, hyperglycemia, leukocytosis, and conscious disturbance on presentation, elevated NT-proBNP was associated with a 22.5-fold (95% confidence interval, 3.56-142.66) increased risk of 3-day mortality. We have further improved the specificity and AUROC values by the HFMD laboratory score, which combines NT-proBNP, leukocytosis, and hyperglycemia.

CONCLUSIONS

Routine admission surveillance for NT-proBNP is useful for identifying patients with HFMD at risk for mortality. Further studies are needed to determine whether early intervention in patients with highly elevated NT-proBNP can improve outcome.

Hand, foot and mouth disease: current knowledge on clinical manifestations, epidemiology, aetiology and prevention

For a long time, hand, foot and mouth disease (HFMD) was seen as a mild viral infection characterized by typical clinical manifestations that spontaneously resolved in a few days without complications. In the past two decades, HFMD has received new attention because of evidence that this disease could have clinical, epidemiological and aetiological characteristics quite different from those initially thought. In contrast to previous beliefs, it has been clarified that HFMD can be associated with complications, leading to severe neurological sequelae and, rarely, to death. This finding has led to an enormous number of studies that have indicated that several viruses in addition to those known to be causes of HFMD could be associated with the development of disease. Moreover, it was found that if some viruses were more common in some geographic areas, frequent modification of the molecular epidemiology of the infecting strains could lead to outbreaks caused by infectious agents significantly different from those previously circulating. Vaccines able to confer protection against the most common aetiologic agents in a given country have been developed. However, simultaneous circulation of more than one causative virus and modification of the molecular epidemiology of infectious agents make preparations based on a single agent relatively inadequate. Vaccines with multiple components are a possible solution. However, several problems concerning their development must be solved before adequate prevention of severe cases of HFMD can be achieved.

Severity and burden of hand, foot and mouth disease in Asia: a modelling study

Background

Hand, foot and mouth disease (HFMD) affects millions of children across Asia annually, leading to an increase in implemented control policies such as surveillance, isolation and social distancing in affected jurisdictions. However, limited knowledge of disease burden and severity causes difficulty in policy optimisation as the associated economic cost cannot be easily estimated. We use a data synthesis approach to provide a comprehensive picture of HFMD disease burden, estimating infection risk, symptomatic rates, the risk of complications and death, and overall disability-adjusted life-year (DALY) losses, along with associated uncertainties.

Methods

Complementary data from a variety of sources were synthesised with mathematical models to obtain estimates of severity of HFMD. This includes serological and other data extracted through a systematic review of HFMD epidemiology previously published by the authors, and laboratory investigations and sentinel reports from Singapore's surveillance system.

Results

HFMD is estimated to cause 96 900 (95% CI 40 600 to 259 000) age-weighted DALYs per annum in eight high-burden countries in East and Southeast Asia, with the majority of DALYs attributed to years of life lost. The symptomatic case hospitalisation rate of HFMD is 6% (2.8%-14.9%), of which 18.7% (6.7%-31.5%) are expected to develop complications. 5% (2.9%-7.4%) of such cases are fatal, bringing the overall case fatality ratio to be 52.3 (24.4-92.7) per 100 000 symptomatic infections. In contrast, the EV-A71 case fatality ratio is estimated to be at least 229.7 (75.4-672.1) per 100 000 symptomatic cases. Asymptomatic rate for EV-A71 is 71.4% (68.3%-74.3%) for ages 1-4, the years of greatest incidence.

Conclusion

Despite the high incidence rate of HFMD, total DALY due to HFMD is limited in comparison to other endemic diseases in the region, such as dengue and upper respiratory tract infection. With the majority of DALY caused by years of life lost, it is possible to mitigate most with increased EV-A71 vaccine coverage.

Epidemiological and serological surveillance of hand-foot-and-mouth disease in Shanghai, China, 2012-2016

Aside from enterovirus 71 (EV71) and coxsackie virus A16 (CV-A16), viruses that are known to cause hand-foot-and-mouth disease (HFMD), epidemiological profiles of other enteroviruses that induce HFMD are limited. We collected 9949 laboratory surveillance HFMD cases and 1230 serum samples from infants and children in Shanghai from 2012–2016. Since 2013, CV-A6 has displaced EV71 and CV-A16 to become the predominant serotype. Interestingly, novel epidemiological patterns in EV71 and CV-A16 infections were observed, with one large peak in both 2012 and 2014, followed by two smaller peaks in the respective following years (2013 and 2015). Through sequencing, we found that C4a, B1b, D-Cluster-1 and B constituted the major subgenotypes of EV71, CV-A16, CV-A6 and CV-A10, respectively. Among healthy individuals, 50.49% and 54.23% had positive neutralising antibodies (NtAbs) against EV71 and CV-A16, respectively, indicating that EV71 and CV-A16 silent infections were common. These populations may be an important potential source of infection. The overall seropositive rate of EV71 NtAbs showed a fluctuating, markedly downward trend, indicating the potential risk of a future EV71 epidemic. High CV-A16 NtAb seroprevalence corroborated a documented CV-A16 ‘silent’ epidemic. Children aged 1–5 years had the lowest EV71 NtAb seropositive rate, whereas those aged 1–2 years exhibited the lowest CV-A16 NtAb seropositive rate. This is the first comprehensive investigation of the epidemiology and aetiology, as well as the seroprevalence, of HFMD in Shanghai between 2012 and 2016. This study provides the latest insights into developing a more efficient HMFD vaccination programme.

Application of seasonal auto-regressive integrated moving average model in forecasting the incidence of hand-foot-mouth disease in Wuhan, China

Outbreaks of hand-foot-mouth disease (HFMD) have occurred many times and caused serious health burden in China since 2008. Application of modern information technology to prediction and early response can be helpful for efficient HFMD prevention and control. A seasonal auto-regressive integrated moving average (ARIMA) model for time series analysis was designed in this study. Eighty-four-month (from January 2009 to December 2015) retrospective data obtained from the Chinese Information System for Disease Prevention and Control were subjected to ARIMA modeling. The coefficient of determination (R ²), normalized Bayesian Information Criterion (BIC) and Q-test P value were used to evaluate the goodness-of-fit of constructed models. Subsequently, the best-fitted ARIMA model was applied to predict the expected incidence of HFMD from January 2016 to December 2016. The best-fitted seasonal ARIMA model was identified as (1,0,1)(0,1,1)₁₂, with the largest coefficient of determination (R ²=0.743) and lowest normalized BIC (BIC=3.645) value. The residuals of the model also showed non-significant autocorrelations (P _{Box-Ljung (Q)}=0.299). The predictions by the optimum ARIMA model adequately captured the pattern in the data and exhibited two peaks of activity over the forecast interval, including a major peak during April to June, and again a light peak for September to November. The ARIMA model proposed in this study can forecast HFMD incidence trend effectively, which could provide useful support for future HFMD prevention and control in the study area. Besides, further observations should be added continually into the modeling data set, and parameters of the models should be adjusted accordingly.

Cost-effectiveness of a national enterovirus 71 vaccination program in China

BACKGROUND AND AIMS

Enterovirus 71 (EV71) has caused great morbidity, mortality, and use of health service in children younger than five years in China. Vaccines against EV71 have been proved effective and safe by recent phase 3 trials and are now available in China. The purpose of this study was to evaluate the health impact and cost-effectiveness of a national EV71 vaccination program in China.

METHODS

Using Microsoft Excel, a decision model was built to calculate the net clinical and economic outcomes of EV71 vaccination compared with no EV71 vaccination in a birth cohort of 1,000,000 Chinese children followed for five years. Model parameters came from published epidemiology, clinical and cost data.

RESULTS

In the base-case, vaccination would annually avert 37,872 cases of hand, foot and mouth disease (HFMD), 2,629 herpangina cases, 72,900 outpatient visits, 6,363 admissions to hospital, 29 deaths, and 945 disability adjusted life years. The break-even price of the vaccine was $5.2/dose. When the price was less than $8.3 or $14.6/dose, the vaccination program would be highly cost-effective or cost-effective, respectively (incremental cost-effectiveness ratio less than or between one to three times China GDP per capita, respectively). In one-way sensitivity analyses, the HFMD incidence was the only influential parameter at the price of $5/dose.

CONCLUSIONS

Within the price range of current routine vaccines paid by the government, a national EV71 vaccination program would be cost-saving or highly cost-effective to prevent EV71 related morbidity, mortality, and use of health service among children younger than five years in China. Policy makers should consider including EV71 vaccination as part of China's routine childhood immunization schedule.

Epidemiological Features of Hand, Foot and Mouth Disease during the Period of 2008-14 in Wenzhou, China

This study aimed to analyze the epidemiological characteristics of hand, foot and mouth disease (HFMD) during 2008-14 in Wenzhou, China. The epidemiological data of HFMD retrieved from the Wenzhou Center for Disease Control and Prevention were retrospectively analyzed. HFMD infections with enterovirus 71 (EV71), Cox A16 or other pathogens were further verified by polymerase chain reaction (PCR) and real-time PCR. A total of 213 617 cases of HFMD were reported between 2008 and 2014 in Wenzhou. The average incidence was 384.31 of 100 000, and the fatality rate was 0.14‰. The incidence of HFMD peaked between April and July, and it occurred more frequently in males than in females. Approximately 92.68% of the HFMD patients were children aged <5 years. Nearly 80% of the cases were diagnosed within 2 days after onset. The major HFMD pathogen was EV71. This study suggested that appropriate comprehensive prevention and control measures should be taken to avoid the spread of HFMD.

Valine/isoleucine variants drive selective pressure in the VP1 sequence of EV-A71 enteroviruses

BACKGROUND

In 2011-2012, Northern Vietnam experienced its first large scale hand foot and mouth disease (HFMD) epidemic. In 2011, a major HFMD epidemic was also reported in South Vietnam with fatal cases. This 2011-2012 outbreak was the first one to occur in North Vietnam providing grounds to study the etiology, origin and dynamic of the disease. We report here the analysis of the VP1 gene of strains isolated throughout North Vietnam during the 2011-2012 outbreak and before.

METHODS

The VP1 gene of 106 EV-A71 isolates from North Vietnam and 2 from Central Vietnam were sequenced. Sequence alignments were analyzed at the nucleic acid and protein level. Gene polymorphism was also analyzed. A Factorial Correspondence Analysis was performed to correlate amino acid mutations with clinical parameters.

RESULTS

The sequences were distributed into four phylogenetic clusters. Three clusters corresponded to the subgenogroup C4 and the last one corresponded to the subgenogroup C5. Each cluster displayed different polymorphism characteristics. Proteins were highly conserved but three sites bearing only Isoleucine (I) or Valine (V) were characterized. The isoleucine/valine variability matched the clusters. Spatiotemporal analysis of the I/V variants showed that all variants which emerged in 2011 and then in 2012 were not the same but were all present in the region prior to the 2011-2012 outbreak. Some correlation was found between certain I/V variants and ethnicity and severity.

CONCLUSIONS

The 2011-2012 outbreak was not caused by an exogenous strain coming from South Vietnam or elsewhere but by strains already present and circulating at low level in North Vietnam. However, what triggered the outbreak remains unclear. A selective pressure is applied on I/V variants which matches the genetic clusters. I/V variants were shown on other viruses to correlate with pathogenicity. This should be investigated in EV-A71. I/V variants are an easy and efficient way to survey and identify circulating EV-A71 strains.

Epidemiology of 45,616 suspect cases of Hand, Foot and Mouth Disease in Chongqing, China, 2011-2015

Epidemiology and etiology of hand, foot, and mouth disease (HFMD) based on large sample size or evaluation of detection for more enterovirus serotypes are not well investigated in Chongqing of China. 45,616 suspect HFMD patients were prospectively enrolled among whom 21,615 were laboratory confirmed HFMD cases over a 5-year period (January 2011 to December 2015). Their epidemiological, clinical, and laboratory data were extracted and stratified by month, age, sex, disease severity, and enterovirus serotype. Subsequently 292 non-EV-A71/CV-A16 HFMD confirmed cases were randomly selected in three consecutive outbreaks to detect CV-A6 and CV-A10, using RT-PCR. Results showed that the HFMD epidemic peaked in early summer and autumn. The median age of onset was 2.45 years with a male-to-female ratio of 1.54:1, and with children under 5 years of age accounting for 92.54% of all confirmed cases. EV-A71 and CV-A16 infection accounted for only 36.05% (7793/21615) of total confirmed cases while EV-A71 accounted for 59.64% (232/389) of severe cases. Importantly, the proportion of EV-A71 infection generally increased with age which showed rapid growth in severe cases. CV-A6 and CV-A10 were tested positive in Chongqing, but CV-A6 had greater positive rates of 62.33% while CV-A10 had 4.79% in non-EV-A71/CV-A16 HFMD confirmed cases.

Relationship between serologic response and clinical symptoms in children with enterovirus 71-infected hand-foot-mouth disease

This study aimed to explore the correlation between clinical symptoms, including rash and fever, and serum antibody reaction to enterovirus 71 (EV71) infection in children hospitalized due to hand-foot-mouth disease (HFMD). From May 2014 to July 2014, a total of 547 children hospitalized due to HFMD in Children's Hospital of Fudan University were enrolled retrospectively. RNA levels of EV71 and CA16 in fecal, serum, and cerebrospinal fluid specimens were measured using quantitative real-time RT-PCR, and EV71-IgM antibody in the serum was detected using immune colloidal gold assays. Of the 547 fecal specimens, 296 were EV71 RNA positive, 109 were CA16 RNA positive, and 8 were positive for both EV71 RNA and CA16 RNA. The total positive rate for either EV71 or CA16 in feces was 72.58% (397/547). Additionally, 544 serum specimens were collected, and 409 were EV71-IgM positive (75.18%). The duration of rash and fever was found to be correlated to the positive rate of serum EV71-IgM, and the positive rate of serum EV71-IgM plus EV71 RNA in feces. The positive rates of serum EV71-IgM and serum EV71-IgM plus EV71 RNA in fecal collected at day 3 of fever were 79.7% and 52.8%, respectively. In conclusion, EV71 and CA16 were found to be the major pathogens responsible for the epidemics of HFMD in children during May to July 2014 in Shanghai, China. There is a close relationship between the positive rate of serum EV71-IgM and the duration of fever and rash.

The Epidemiology of Hand, Foot and Mouth Disease in Asia: A Systematic Review and Analysis

CONTEXT

Hand, foot and mouth disease (HFMD) is a widespread pediatric disease caused primarily by human enterovirus 71 (EV-A71) and Coxsackievirus A16 (CV-A16).

OBJECTIVE

This study reports a systematic review of the epidemiology of HFMD in Asia.

DATA SOURCES

PubMed, Web of Science and Google Scholar were searched up to December 2014.

STUDY SELECTION

Two reviewers independently assessed studies for epidemiologic and serologic information about prevalence and incidence of HFMD against predetermined inclusion/exclusion criteria.

DATA EXTRACTION

Two reviewers extracted answers for 8 specific research questions on HFMD epidemiology. The results are checked by 3 others.

RESULTS

HFMD is found to be seasonal in temperate Asia with a summer peak and in subtropical Asia with spring and fall peaks, but not in tropical Asia; evidence of a climatic role was identified for temperate Japan. Risk factors for HFMD include hygiene, age, gender and social contacts, but most studies were underpowered to adjust rigorously for confounding variables. Both community-level and school-level transmission have been implicated, but their relative importance for HFMD is inconclusive. Epidemiologic indices are poorly understood: No supporting quantitative evidence was found for the incubation period of EV-A71; the symptomatic rate of EV-A71/Coxsackievirus A16 infection was from 10% to 71% in 4 studies; while the basic reproduction number was between 1.1 and 5.5 in 3 studies. The uncertainty in these estimates inhibits their use for further analysis.

LIMITATIONS

Diversity of study designs complicates attempts to identify features of HFMD epidemiology.

CONCLUSIONS

Knowledge on HFMD remains insufficient to guide interventions such as the incorporation of an EV-A71 vaccine in pediatric vaccination schedules. Research is urgently needed to fill these gaps.

Using a Negative Binomial Regression Model for Early Warning at the Start of a Hand Foot Mouth Disease Epidemic in Dalian, Liaoning Province, China

Background

The hand foot and mouth disease (HFMD) is a human syndrome caused by intestinal viruses like that coxsackie A virus 16, enterovirus 71 and easily developed into outbreak in kindergarten and school. Scientifically and accurately early detection of the start time of HFMD epidemic is a key principle in planning of control measures and minimizing the impact of HFMD. The objective of this study was to establish a reliable early detection model for start timing of hand foot mouth disease epidemic in Dalian and to evaluate the performance of model by analyzing the sensitivity in detectability.

Methods

The negative binomial regression model was used to estimate the weekly baseline case number of HFMD and identified the optimal alerting threshold between tested difference threshold values during the epidemic and non-epidemic year. Circular distribution method was used to calculate the gold standard of start timing of HFMD epidemic.

Results

From 2009 to 2014, a total of 62022 HFMD cases were reported (36879 males and 25143 females) in Dalian, Liaoning Province, China, including 15 fatal cases. The median age of the patients was 3 years. The incidence rate of epidemic year ranged from 137.54 per 100,000 population to 231.44 per 100,000population, the incidence rate of non-epidemic year was lower than 112 per 100,000 population. The negative binomial regression model with AIC value 147.28 was finally selected to construct the baseline level. The threshold value was 100 for the epidemic year and 50 for the non- epidemic year had the highest sensitivity(100%) both in retrospective and prospective early warning and the detection time-consuming was 2 weeks before the actual starting of HFMD epidemic.

Conclusions

The negative binomial regression model could early warning the start of a HFMD epidemic with good sensitivity and appropriate detection time in Dalian.

Study of the epidemiology and etiological characteristics of hand, foot, and mouth disease in Suzhou City, East China, 2011-2014

Hand, foot, and mouth disease (HFMD) is a common childhood illness that is caused by enteroviruses, and the prevalence of HFMD in China and around the world has resulted in a huge disease burden. Since 2010, the HFMD incidence has been the highest among infectious diseases in Suzhou, China. To investigate the epidemical, features, etiological characteristics, and clinical characteristics of HFMD in Suzhou City, East China, from 2011 to 2014. We retrospectively analyzed HFMD epidemiological data in Suzhou from 2011 to 2014. A total of 80,723 outpatients in the city of Suzhou were diagnosed with HFMD, including 1,846 severe cases. There were 2,387 (3.0 %) laboratory-confirmed cases, 807 of which exhibited severe symptoms. All analyses were stratified by age, disease severity, laboratory confirmation status, and enterovirus subtype. From 2011 to 2014, HFMD mainly affected children aged 1-3, and boys were more affected than girls. The highest peak incidences of HFMD occurred in May or June from 2011 to 2014, and lower peak incidences were observed from November to December and in districts with higher humidity. Enterovirus 71 and coxsackievirus A16 were the predominant viral genotypes in Suzhou in 2011 to 2012 and 2014, and the severe cases mainly correlated with EV71 subtypes. In 2013, other EVs were dominant. The proportion of patients with severe disease decreased significantly, and the VP1 capsid proteins of EV71 and CA16 from severe and mild cases were nearly identical. This study shows that it is time to start monitoring EVs in China and that we should accelerate vaccine research and develop public-health interventions for the control and prevention of HFMD, all of which will play an important role in the prevention of HFMD.

A literature review and case report of hand, foot and mouth disease in an immunocompetent adult

Background

To report an uncommon case of hand, foot and mouth disease, (HFMD) in an immunocompetent adult; a highly infectious disease, characterized by the appearance of vesicles on the mouth, hands and feet, associated with coxsackieviruses and enteroviruses; including a literature review.

Case report

A 23 year Caucasian male with no medical or surgical history, no allergies, was not taking any medication and smoked ten cigarettes a day, suffering from discomfort in the oral cavity; itching, burning and pain when swallowing associated with small erythematous lesions located on the hard palate, and small ulcers in tonsillar pillars and right buccal mucosa. Mild fever of 37.8 °C and general malaise. The patient reported he had had contact with a child diagnosed with HFMD. From his background and symptoms, the patient was diagnosed with HFMD. Following symptomatic treatment, the symptoms remitted in 7 days.

Methods

A literature review in MEDLINE (PubMed). The inclusion criteria were for studies on humans over the last 5 years, using the keywords HFMD.

Results

We found 925 articles, which were subsequently reduced to 52 documents after applying the inclusion criteria. Maculopapular lesions were found on hands and feet.

Conclusions

Dentists may have a key role diagnosing the disease. A surveillance system to predict future outbreaks, encourage early diagnosis, put appropriate public health measures in place and research vaccine development is vitally important in order to control the disease.

Intestinal detoxification time of hand-foot-and-mouth disease in children with EV71 infection and the related factors

BACKGROUND

Hand-foot-and-mouth disease (HFMD) is a common pediatric infectious disease caused by a variety of intestinal viruses. Enterovirus 71 (EV71) is the primary pathogen that might cause severe symptoms and even death in children with HFMD. This study aimed to investigate the intestinal detoxification time of HFMD children with EV71 infection and its related factors.

METHODS

Sixty-five HFMD children with EV71 infection were followed up. Their stool samples were collected once every 4 to 7 days. Viral nucleic acids were detected by fluorescent polymerase chain reaction until the results became negative. The positive rates of viral nucleic acids were analyzed by the Kaplan-Meier method. The Log-rank test and Cox-Mantel test were used to analyze factors affecting the HFMD children with EV71 infection.

RESULTS

On the 2nd, 4th, 6th and 10th week, the positive rates of viral nucleic acids in stool samples of the 65 children were 94.6%, 48.1%, 17.2% and 0, respectively. Univariate analysis showed that the intestinal detoxification time of the children were related to gender, pre-admission disease course, severity of disease, and use of steroids or gamma globulin (P<0.05). Multivariate analysis showed that the severity of disease was an independent factor affecting the intestinal detoxification time (P<0.05), with a relative risk of 2.418.

CONCLUSIONS

The longest intestinal detoxification time of HFMD children with EV71 infection was 10 weeks. The severity of disease was an important factor affecting the intestinal detoxification time of HFMD children with EV71 infection. Severe HFMD children with EV71 infection had a longer intestinal detoxification time.

Structure Elucidation of Coxsackievirus A16 in Complex with GPP3 Informs a Systematic Review of Highly Potent Capsid Binders to Enteroviruses

The replication of enterovirus 71 (EV71) and coxsackievirus A16 (CVA16), which are the major cause of hand, foot and mouth disease (HFMD) in children, can be inhibited by the capsid binder GPP3. Here, we present the crystal structure of CVA16 in complex with GPP3, which clarifies the role of the key residues involved in interactions with the inhibitor. Based on this model, in silico docking was performed to investigate the interactions with the two next-generation capsid binders NLD and ALD, which we show to be potent inhibitors of a panel of enteroviruses with potentially interesting pharmacological properties. A meta-analysis was performed using the available structural information to obtain a deeper insight into those structural features required for capsid binders to interact effectively and also those that confer broad-spectrum anti-enterovirus activity.

Clinical Features for Mild Hand, Foot and Mouth Disease in China

Background

Mild hand, foot and mouth disease (HFMD) is at a critical stage owing to its ease of communicability and a higher risk of developing severe complications and death. Clinical diagnosis of mild HFMD was made by the presenting symptoms and signs (symptoms in brief) alone. We aim to evaluate the frequencies of symptoms in a retrospective case series study.

Methods

We collected epidemiological, demographic, clinical, and laboratory data from outpatient and inpatient settings on the clinical data warehouse system. We principally described the frequencies of symptoms of mild HFMD. Correlations between symptoms with laboratory-confirmed cases were then analyzed.

Results

The clinical data warehouse system included 3649 probable cases, between 2010 and 2012, of which 956 (26.20%) were laboratory confirmed. The peak incidence was identified in children 2 years of age. A total of 370 of the 956 laboratory confirmed cases (38.70%) were associated with enterovirus 71 (EV71). Logistic regression analysis adjusted for geographical variables, age, sex, month of onset, and time from onset to diagnosis showed that the clinical features constipation (P<0.0001; adjusted OR, 95%CI (2.99, 2.28–3.91)), and blisters (P<0.0001; adjusted OR, 95%CI (2.16, 1.82–2.56)) were positively correlated with the confirmed cases.

Conclusions

This is the largest case series study, including all the guideline-mentioned symptoms of mild HFMD. Our findings suggest that blisters and constipation should be considered as potential warning signs while front-line clinicians manage surges of children diagnosed with mild HFMD during a pandemic.

Enterovirus 71 infection in children with hand, foot, and mouth disease in Shanghai, China: epidemiology, clinical feature and diagnosis

BACKGROUND

In 2012 a large outbreak of hand, foot, and mouth disease (HFMD) widely spread over China, causing more than 2 million cases and 567 deaths. Our purpose was to characterize the major pathogens responsible for the 2012 HFMD outbreak and analyze the genetic characterization of the enterovirus 71 (EV71) strains in Shanghai; also, to analyze the dynamic patterns of neutralizing antibody (NAb) against EV71 and evaluate the diagnostic value of several methods for clinical detection of EV71.

METHODS

Clinical samples including stool, serum and CSF were collected from 396 enrolled HFMD inpatients during the peak seasons in 2012. We analyzed the molecular epidemiology, clinical feature, and diagnostic tests of EV71 infection.

RESULTS

EV71 was responsible for 60.35 % of HFMD inpatients and 88.46 % of severe cases. The circulating EV71 strains belonged to subgenogroup C4a. The nucleotide sequences of VP1 between severe cases and uncomplicated cases shared 99.2 ~ 100 % of homology. Among 218 cases with EV71 infection, 211 (96.79 %) serum samples showed NAb positive against EV71 and NAb titer reached higher level 3 days after disease onset. Of 92 cases with EV71-associated meningitis or encephalitis, 5 (5.43 %) of 92 had EV71 RNA detected in CSF samples. The blood anti-EV71 IgM assay showed a sensitivity of 93.30 % and a specificity of 50 %.

CONCLUSIONS

EV71 C4a remained the predominant subgenotype circulating in Shanghai. The severity of the EV71 infection is not associated with the virulence determinants in VP1. RT-PCR together with IgM detection can enhance the early diagnosis of severe EV71-associated HFMD.

Epidemiological characteristics and influential factors of hand, foot and mouth disease (HFMD) reinfection in children in Anhui province

Hand, foot and mouth disease (HFMD) is an acute contagious condition caused by a spectrum of human enteroviruses. HFMD reinfection is common in the absence of cross-protection from other virus subtypes. This study focused on reinfection in children in Anhui province, China between 2008 and 2013 using surveillance system data. We classified 8960 cases as reinfected, corresponding to a rate of 2·02%. The reinfection rate was higher in boys than in girls [odds ratio (OR) 1·27, 95% confidence interval (CI) 1·21-1·32, P < 0·001], children aged < 3 years (OR 3·82, 95% CI 3·58-4·07, P < 0·001), and children living in rural areas (OR 1·09, 95% CI 1·04-1·14, P = 0·001). The reinfection rate in children who were originally infected with non-enterovirus A71 (non-EVA71) enteroviruses was higher than those infected with EVA71 (OR 1·36, 95% CI 1·02-1·80, P = 0·034). Influential factors of reinfection rate included annual incidence (β coefficient = 0·715, P = 0·002) and the proportion of EVA71 in patients with mild HFMD (β coefficient = -0·509, P = 0·018). These results demonstrate that boys aged <3 years, especially those in rural areas or regions with a lower EVA71 proportion are more prone to reinfection, and specific health education programmes should be developed to protect these susceptible populations.

Is a multivalent hand, foot, and mouth disease vaccine feasible?

Enterovirus A infections are the primary cause of hand, foot and mouth disease (HFMD) in infants and young children. Although enterovirus 71 (EV-A71) and coxsackievirus A16 (CV-A16) are the predominant causes of HFMD epidemics worldwide, EV-A71 has emerged as a major neurovirulent virus responsible for severe neurological complications and fatal outcomes. HFMD is a serious health threat and economic burden across the Asia-Pacific region. Inactivated EV-A71 vaccines have elicited protection against EV-A71 but not against CV-A16 infections in large efficacy trials. The current development of a bivalent inactivated EV-A71/CV-A16 vaccine is the next step toward that of multivalent HFMD vaccines. These vaccines should ultimately include other prevalent pathogenic coxsackieviruses A (CV-A6 and CV-A10), coxsackieviruses B (B3 and B5) and echovirus 30 that often co-circulate during HFMD epidemics and can cause severe HFMD, aseptic meningitis and acute viral myocarditis. The prospect and challenges for the development of such multivalent vaccines are discussed.

Hand-foot-and-mouth disease epidemiological status and relationship with meteorological variables in Guangzhou, southern China, 2008-2012

Hand-foot-and-mouth disease (HFMD) is becoming one of the extremely common airborne and contact transmission diseases in Guangzhou, southern China, leading public health authorities to be concerned about its increased incidence. In this study, it was used an ecological study plus the negative binomial regression to identify the epidemic status of HFMD and its relationship with meteorological variables. During 2008-2012, a total of 173,524 HFMD confirmed cases were reported, 12 cases of death, yielding a fatality rate of 0.69 per 10,000. The annual incidence rates from 2008 to 2012 were 60.56, 132.44, 311.40, 402.76, and 468.59 (per 100,000), respectively, showing a rapid increasing trend. Each 1 °C rise in temperature corresponded to an increase of 9.47% (95% CI 9.36% to 9.58%) in the weekly number of HFMD cases, while a one hPa rise in atmospheric pressure corresponded to a decrease in the number of cases by 7.53% (95% CI -7.60% to -7.45%). Similarly, each one percent rise in relative humidity corresponded to an increase of 1.48% or 3.3%, and a one meter per hour rise in wind speed corresponded to an increase of 2.18% or 4.57%, in the weekly number of HFMD cases, depending on the variables considered in the model. These findings revealed that epidemic status of HFMD in Guangzhou is characterized by high morbidity but low fatality. Weather factors had a significant influence on the incidence of HFMD.

Spatio-temporal analysis of the relationship between climate and hand, foot, and mouth disease in Shandong province, China, 2008-2012

Background

Hand, foot, and mouth disease (HFMD) is the most common communicable disease in China. Shandong Province is one of the most seriously affected areas. The distribution of HFMD had spatial heterogeneity and seasonal characteristic in this setting. The aim of this study was to explore the associations between climate and HFMD by a Bayesian approach from spatio-temporal interactions perspective.

Methods

The HFMD data of Shandong Province during 2008–2012 were derived from the China National Disease Surveillance Reporting and Management System. And six climatic indicators were obtained from the Meteorological Bureau of Shandong Province. The global spatial autocorrelation statistic (Moran’s I) was used to detect the spatial autocorrelation of HFMD cases in each year. The optimal one among four Bayesian models was further adopted to estimate the relative risk of the occurrence of HFMD via Markov chain Monte Carlo.

Results

The annual average incidence rate of HFMD was 104.40 per 100,000 in Shandong Province. Positive spatial autocorrelation appeared at county level (Moran’s I ≥0.30, P < 0.001). The best fitting Spatio-temporal interactive model showed that annual average temperature, annual average pressure, annual average relative humidity, annual average wind speed and annual sunshine hours were significantly positive related to the occurrence of HFMD. The estimated relative risk of 36, 87, 91, 79, 65 out of 140 counties for 2008–2012 respectively were significantly more than 1.

Conclusions

There were obvious spatio-temporal heterogeneity of HFMD in Shandong Province, and the climatic indicators were associated with the epidemic of HFMD. Bayesian approach should be recommended to capture the spatial-temporal pattern of HFMD.

Rapidly rising incidence of childhood type 1 diabetes in Chinese population: epidemiology in Shanghai during 1997-2011

The aim of this study was to investigate incidence trend of childhood type 1 diabetes in Shanghai, a megalopolis in east China. We established a population-based retrospective registry for the disease in the city's registered population during 1997-2011 and collected 622 incident type 1 diabetes in children aged 0-14 years. Standardized incidence rates and 95 % CI were estimated by applying the capture-recapture method and assuming Poisson distribution. Incidence trend was analyzed using the Poisson regression model. The mean annual incidence of childhood type 1 diabetes was 3.1 per 100,000 person-years. We did not observe significant difference in incidence between boys and girls. The incidence is unstable and had a mean annual increase 14.2 % per year during the studied period. A faster annual increase was observed in boys, warmer seasons, and in the outer regions of the city. If present trends continue, the number of new type 1 diabetes cases will double from 2016 to 2020, and prevalent cases will sextuple by 2025. Our results showed the incidence of childhood type 1 diabetes was rising rapidly in Shanghai. More studies are needed to analyze incidence changes in other regions of China for appropriate allocation of healthcare resources.

Detection of hand, foot and mouth disease in the yucatan peninsula of Mexico

We report a case of hand, foot and mouth disease (HFMD) in a 5-year-old male from Merida City in the Yucatan Peninsula of Mexico. A clinical and physical examination revealed that the patient had symptoms typical of HFMD, including fever, fatigue, odynophagia, throat edema, hyperemia, lesions on the hands and feet, and blisters in the oral cavity. The patient fully recovered after a convalescence period of almost three weeks. Reverse transcription-polymerase chain reaction and nucleotide sequencing revealed that the etiological agent was enterovirus 71 (EV71). The sequence has greatest (90.4%) nucleotide identity to the corresponding regions of EV71 isolates from the Netherlands and Singapore. Although HFMD is presumably common in Mexico, surprisingly there are no data in the PubMed database to support this. This case report provides the first peer-reviewed evidence of HFMD in Mexico.

Association analysis of polymorphisms in OAS1 with susceptibility and severity of hand, foot and mouth disease

Hand, foot and mouth disease (HFMD) is a common childhood illness that mainly affects Asian children under the age of 5 years. Human enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are the most common pathogens of HFMD. It is imperative that the susceptible population is screened early and that the severe illness population can be identified via genetic variation detection in children. Four single-nucleotide polymorphisms (SNP) [2'-5'-oligoadenylate synthetase1 (OAS1) rs10774671, selectin P ligand (SELPLG) rs2228315, scavenger receptor class B member 2 (SCARB2) rs41284767 and interleukin 28B (IL28B) rs12979860] were determined by Taqman assays in 333 HFMD samples and 163 control samples. The rs2228315, rs41284767 and rs12979860 polymorphisms did not differ significantly between HFMD patients and the controls, but the prevalence of the rs10774671 polymorphism was significantly different between the control children and children infected with CA16 (GG genotype vs. AA + AG genotype, P < 0.05). Children with the GG genotype were more susceptible to CA16-type HFMD. Furthermore, the rs10774671 genotype distribution was clearly different between children with severe HFMD and those with mild HFMD [P < 0.05, OR 0.240, 95% CI (0.071-0.809)]. HFMD children with the AA+AG genotype were more likely to progress to encephalitis than were those with the GG genotype. Plasma γ-interferon (IFN) expression levels among control children and the mild and severe HFMD children were detected by ELISA. Those with mild HFMD had higher γ-IFN expression levels compared with those with severe HFMD (P < 0.05). In addition, there is a significant correlation between γ-IFN levels and OAS1 rs10774671 SNP, as analysed by linear correlation assay. The GG genotype correlated with higher γ-IFN levels (P < 0.05). In short, the OAS1 rs10774671 SNP GG genotype contributed to CA16 susceptibility and was associated with the development of mild HFMD.

Application of a new hybrid model with seasonal auto-regressive integrated moving average (ARIMA) and nonlinear auto-regressive neural network (NARNN) in forecasting incidence cases of HFMD in Shenzhen, China

BACKGROUND

Outbreaks of hand-foot-mouth disease (HFMD) have been reported for many times in Asia during the last decades. This emerging disease has drawn worldwide attention and vigilance. Nowadays, the prevention and control of HFMD has become an imperative issue in China. Early detection and response will be helpful before it happening, using modern information technology during the epidemic.

METHOD

In this paper, a hybrid model combining seasonal auto-regressive integrated moving average (ARIMA) model and nonlinear auto-regressive neural network (NARNN) is proposed to predict the expected incidence cases from December 2012 to May 2013, using the retrospective observations obtained from China Information System for Disease Control and Prevention from January 2008 to November 2012.

RESULTS

The best-fitted hybrid model was combined with seasonal ARIMA [Formula: see text] and NARNN with 15 hidden units and 5 delays. The hybrid model makes the good forecasting performance and estimates the expected incidence cases from December 2012 to May 2013, which are respectively -965.03, -1879.58, 4138.26, 1858.17, 4061.86 and 6163.16 with an obviously increasing trend.

CONCLUSION

The model proposed in this paper can predict the incidence trend of HFMD effectively, which could be helpful to policy makers. The usefulness of expected cases of HFMD perform not only in detecting outbreaks or providing probability statements, but also in providing decision makers with a probable trend of the variability of future observations that contains both historical and recent information.

The population-based health effect of hand, foot and mouth disease in children in Shanghai

BACKGROUND

An effective enterovirus 71 (EV71) vaccine is needed to control the annual outbreaks of hand, foot and mouth disease (HFMD) in China. Adequate epidemiologic data relating to HFMD are needed to make decisions about appropriate public health interventions and implementation of the new EV71 vaccine.

METHODS

We analyzed the population-based epidemiologic characteristics, clinical outcome and laboratory investigation of the 2011 HFMD outbreak in children based on the citywide surveillance system in Shanghai.

RESULTS

The incidence rate of HFMD was 25.8 per 1000 in children <10 years of age in Shanghai in 2011, ranging from 2.5 per 1000 in the age group 7 to 9.9 years to 48.4 per 1000 in the age group 3 to 3.9 years. Children 1 to 1.9 years were at the highest risk of developing severe complications and most susceptible to HFMD. Boys and migrant children had significantly increased risks of contracting HFMD and developing severe disease. More institutional clusters/outbreaks occurred in the winter peak months than in the summer peak months. Migrant young children played a central role in the spread of HFMD in the community. EV71 was identified in 39.7% of mild HFMD outpatients, 47.4% of hospitalized patients, 92.1% of severe inpatients with complications, 50% of outbreaks and 38.8% of clusters in institutions.

CONCLUSION

HFMD and EV71 infections have a significant health effect on Shanghai children.

Co-circulation and genomic recombination of coxsackievirus A16 and enterovirus 71 during a large outbreak of hand, foot, and mouth disease in Central China

A total of 1844 patients with hand, foot, and mouth disease (HFMD), most of them were children of age 1–3-year-old, in Central China were hospitalized from 2011 to 2012. Among them, 422 were infected with coxsackievirus A16 (CVA16), 334 were infected with enterovirus 71 (EV71), 38 were co-infected with EV71 and CVA16, and 35 were infected with other enteroviruses. Molecular epidemiology analysis revealed that EV71 and CVA16 were detected year-round, but EV71 circulated mainly in July and CVA16 circulated predominantly in November, and incidence of HFMD was reduced in January and February and increased in March. Clinical data showed that hyperglycemia and neurologic complications were significantly higher in EV71-infected patients, while upper respiratory tract infection and C-reactive protein were significantly higher in CVA16-associated patients. 124 EV71 and 80 CVA16 strains were isolated, among them 56 and 68 EV71 strains were C4a and C4b, while 25 and 55 CVA16 strains were B1a and B1b, respectively. Similarity plots and bootscan analyses based on entire genomic sequences revealed that the three C4a sub-genotype EV71 strains were recombinant with C4b sub-genotype EV71 in 2B–2C region, and the three CVA16 strains were recombinant with EV71 in 2A–2B region. Thus, CVA16 and EV71 were the major causative agents in a large HFMD outbreak in Central China. HFMD incidence was high for children among household contact and was detected year-round, but outbreak was seasonal dependent. CVA16 B1b and EV71 C4b reemerged and caused a large epidemic in China after a quiet period of many years. Moreover, EV71 and CVA16 were co-circulated during the outbreak, which may have contributed to the genomic recombination between the pathogens. It should gain more attention as there may be an upward trend in co-circulation of the two pathogens globally and the new role recombination plays in the emergence of new enterovirus variants.

Hand-foot-and-mouth disease and weather factors in Guangzhou, southern China

Hand-foot-and-mouth disease (HFMD) is becoming one of the common airborne and contact transmission diseases in Guangzhou, southern China, leading public health authorities to be concerned about its increased incidence. In this study, we aimed to examine the effect of weather patterns on the incidence of HFMD in the subtropical city of Guangzhou for the period 2009–2012, and assist public health prevention and control measures. A negative binomial multivariable regression was used to identify the relationship between meteorological variables and HFMD. During the study period, a total of 166 770 HFMD-confirmed cases were reported, of which 11 died, yielding a fatality rate of 0·66/10 000. Annual incidence rates from 2009 to 2012 were 132·44, 311·40, 402·76, and 468·59/1 000 00 respectively. Each 1°C rise in temperature corresponded to an increase of 9·38% (95% CI 8·17–10·51) in the weekly number of HFMD cases, while a 1 hPa rise in atmospheric pressure corresponded to a decrease in the number of cases by 6·80% (95% CI −6·99 to −6·65), having an opposite effect. Similarly, a 1% rise in relative humidity corresponded to an increase of 0·67% or 0·51%, a 1 m/h rise in wind velocity corresponded to an increase of 4·01% or 2·65%, and a 1 day addition in the number of windy days corresponded to an increase of 24·73% or 25·87%, in the weekly number of HFMD cases, depending on the variables considered in the model. Our findings revealed that the epidemic status of HFMD in Guangzhou is characterized by high morbidity but low fatality. Weather factors had a significant influence on occurrence and transmission of HFMD.

Epidemiological features of hand-foot-and-mouth disease in Shenzhen, China from 2008 to 2010

This study analysed the spatio-temporal distribution and propagation of hand-foot-and-mouth disease (HFMD) in Shenzhen from 2008 to 2010. Specifically, we examined the epidemiological data, temporal distribution and spatial distribution, and then the relationship between meteorological, social factors and the number of reported HFMD cases was analysed using Spearman's rank correlation. Finally, a geographically weighted regression model was constructed for the number of reported HFMD cases in 2009. It was found that three independent variables, i.e. the number of reported HFMD cases in 2008 and, annual average temperature and precipitation, had different spatial impacts on the number of reported HFMD cases in 2009. In addition, these variables accounted for the propagation mechanism of HFMD in the centre and east of Shenzhen, where the high incidence rate areas are located. These results will be of great help in understanding the spatio-temporal distribution of HFMD and developing approaches to prevent this disease.

Children of rural-to-urban migrant workers in China are at a higher risk of contracting severe hand, foot and mouth disease and EV71 infection: a hospital-based study

The incidence and severity of hand, foot and mouth disease have increased in mainland China since 2008. Therapies and vaccines are currently at different stages of development. This study aimed to determine the social factors associated with the outbreaks and severity of the disease in Chinese children. A multicentre, prospective, case-controlled study was conducted in Shanghai, Chongqing, Guangzhou and Shantou to identify the sociodemographic and behavioural risk factors for hand, foot and mouth disease. Children hospitalized for hand, foot and mouth disease were randomly enrolled from April to November 2011. Stool samples were collected to test for the presence of enterovirus 71 (EV71). A total of 443 children between 1.6 and 68 months of age were enrolled; 304 were uncomplicated cases and 139 were severe cases with central nervous system involvement. The overall detection rate of EV71 was 54.2%, and the positivity rate of EV71 was significantly higher in the severe group than in the uncomplicated group (82.0% versus 40.9%, odds ratio (OR): 8.35, P=0.000). The children of migrant workers (OR: 3.014, P=0.000) and children attending kindergarten (OR: 2.133, P=0.002) were significantly associated with a severe outcome of the disease (OR: 1.765, P=0.026). Our findings indicate that kindergarten attendance and migrant worker parents are the major risk factors associated with severe hand, foot and mouth disease in children <5 years of age. Future public health intervention vaccination campaigns should consider the particular difficulties of achieving high compliance with multiple-dose vaccination regimens in the children of migrant workers.

Severe hand, foot and mouth disease in Shenzhen, South China: what matters most?

Case report data and a matched case-control study were used to investigate the epidemiological characteristics of hand, foot and mouth disease (HFMD) in children in Shenzhen, China between 2008 and 2011. Multivariate analyses were used to evaluate factors associated with severity of infection. Laboratory tests were performed to determine aetiological identification for samples from 163 severe and fatal cases as well as an outpatient-based HFMD sentinel surveillance system (n = 446). All identified EV71 belonged to sub-genotype C4a. No major changes in the CA16 and EV71 viruses were found until the end of 2011. Annual attack rates and the case-severity ratios (CSRs) rose from 0.82/1000 and 0.56/1000, respectively, in 2008 to 2.12/1000 and 6.13/1000 in 2011. The CSR was higher in migrants than in local residents. The adjusted odds ratio (OR) of having a severe attack for being a migrant was 2.45, having a fever >39°C (OR 5.77), visiting a private clinic (OR 2.65), longer time from symptom onset to diagnosis (OR 1.49), visiting a doctor (OR 1.51), early use of intramuscular pyrazolone (OR 3.36), early use of intravenous glucocorticoids (OR 2.28), or the combination of both (OR 3.75). The mortality and increasing case severity appears to be associated with socioeconomic factors including migration and is of worldwide concern.

Occurrence of hand-foot-and-mouth disease pathogens in domestic sewage and secondary effluent in Xi'an, China

Hand, foot and mouth disease (HFMD), caused by a group of enteric viruses such as Enterovirus 71 (EV71), Coxsackievirus A16 (CVA16) and Coxsackievirus A10 (CVA10), is heavily epidemic in East Asia. This research focused on investigating the occurrence of HFMD pathogens in domestic sewage and secondary effluent before disinfection in a wastewater treatment plant (WWTP) in Xi’an, the largest megacity in northwest China. In order to simultaneously detect all three HFMD pathogens, a semi-nested RT-PCR assay was constructed with a newly designed primer set targeting conservative gene regions from the 5′ untranslated region (UTR) to VP2. As a result, 86% of raw sewage samples and 29% of the secondary effluent samples were positive for the HFMD viral gene, indicating that HFMD pathogens were highly prevalent in domestic wastewater and that they could also persist, even with lower probability, in the secondary effluent before disinfection. Of the three HFMD pathogens, CVA10 was positive in 48% of the total samples, while the occurrences of CVA16 and EV71 were 12% and 2%, respectively. It could thus be stated that CVA10 is the main HFMD pathogen prevailing in the study area, at least during the investigation period. High genetic diversity in the conservative gene region among the same serotype of the HFMD pathogen was identified by phylogenetic analysis, implying that this HFMD pathogen replicates frequently among the population excreting the domestic sewage.

Seroepidemiology of Enterovirus 71 infection prior to the 2011 season in children in Shanghai

BACKGROUND

In 2010, China experienced the largest outbreak on record of Enterovirus 71 (EV71)-associated Hand Foot and Mouth Disease (HFMD) with more than 1.7 million cases, 27,000 patients with severe neurological complications and 905 deaths. Understanding of the seroprevalence of neutralizing antibodies (NAb) against EV71 and their protective role against HFMD in children is crucial for the implementation of future therapeutic and prophylactic intervention.

OBJECTIVES

To correlate the prevalence of NAb against EV71 genotype C4a in children prior to the 2011 epidemic season with severe EV71-associated HFMD disease during the subsequent 2011 epidemic season.

STUDY DESIGN

614 sera samples were collected from children without HFMD. EV71 NAb were tested by a quantitative PCR assay. Samples with NAb ≥1:8 were scored as positive.

RESULTS

122 (19.9%) of 614 sera were EV71-seropositive. The NAb seroprevalence was highest in infants 0-5 months of age (28.6%) and lowest in children 1-1.9 years of age (13.4%). 64.1% of severe EV71-associated HFMD occurred in children 1-2.9 years.

CONCLUSIONS

Despite the large 2010 outbreak, the overall seroprevalence of EV71 in children is relatively low. The seropositive rate of EV71 NAb prior to the 2011 season was inversely correlated with the number of EV71-infected severe cases in 2011. Loss of maternal antibodies in infants and lack of acquired anti-EV71 immunity are responsible for increased proportion of severe HFMD in the 1-2 years age group. Our data suggest that future vaccination campaigns should be initiated as early as 6 months.