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.

Etiologic and epidemiologic analysis of hand, foot, and mouth disease in Guangzhou city: a review of 4,753 cases

OBJECTIVES: This study aimed to review etiological and epidemiological data for hand, foot, and mouth disease (HFMD) cases that occurred between 2008 and 2010 in Guangzhou City, to help develop and implement precautionary measures applicable for future outbreaks. METHODS: The characteristics of 4,753 HFMD episodes were retrospectively reviewed in 4,636 patients reported between 2008 and 2010 by the Guangdong Women and Children's Hospital, which is the national enterovirus monitoring agent and the designated hospital in China for treating severe HFMD. RESULTS: Out of 4,753 incident episodes reviewed, 525 patients were hospitalized; 60% were males. Most patients (93.8%) were children under 5 years old, with a median age at onset of 2.4 years. HFMD incidence peaked in April/May and September/October. From the total, 1,067 (22.4%) infections were positive for human enterovirus 71 (HEV71), 1,094 (23.0%) were positive for coxsackievirus A16 (CA16), and 941 (19.8%) were positive for other common enteroviruses. In contrast, 1,666 (35.0%) cases were negative to HEV71, CA16, and other common enteroviruses. Cross-correlation coefficients demonstrated associations between the number of cases, seasonal temperatures, and humidity. Among hospitalized cases, HEV71 was positive in 261 (24.5%), and 42 (3.9%) critical cases were positive for HEV71. CONCLUSION: Seasonal fluctuations and HEV71 and CA16 were the two key factors influencing the Guangzhou HFMD epidemic. The infection predominantly affected children younger than 5 years old.

Distribution of human enterovirus 71 in brainstem of infants with brain stem encephalitis and infection mechanism / 法医学杂志

OBJECTIVE@#To explore the mechanism that how human enterovirus 71 (EV71) invades the brainstem and how intercellular adhesion molecules-1 (ICAM-1) participates by analyzing the expression and distribution of human EV71, and ICAM-1 in brainstem of infants with brain stem encephalitis.@*METHODS@#Twenty-two brainstem of infants with brain stem encephalitis were collected as the experimental group and 10 brainstems of fatal congenital heart disease were selected as the control group. The sections with perivascular cuffings were selected to observe EV71-VP1 expression by immunohistochemistry method and ICAM-1 expression was detected for the sections with EV71-VP1 positive expression. The staining image analysis and statistics analysis were performed. The experiment and control groups were compared.@*RESULTS@#(1) EV71-VP1 positive cells in the experimental group were mainly astrocytes in brainstem with [dark]-brown particles, and the control group was negative. (2) ICAM-1 positive cells showed [dark]-brown. The expression in inflammatory cells (around blood vessels of brain stem and in glial nodules) and gliocytes increased. The results showed statistical difference comparing with control group (P < 0.05).@*CONCLUSION@#The brainstem encephalitis can be used to diagnose fatal EV71 infection in infants. EV71 can invade the brainstem via hematogenous route. ICAM-1 may play an important role in the pathogenic process.

Echovirus 4 associated to hand, foot and mouth disease / Echovirus 4 associado à doença de mão, pé e boca

Hand, foot and mouth disease (HFMD) is a contagious enteroviral infection occurring primarily in children and characterized by vesicular palmoplantar eruptions and erosive stomatitis. Echovirus 4 (EV-4) has been commonly associated with aseptic meningitis. The association of HFMD with EV-4 has not been reported previously. Two samples of a 14-month child who presented mild fever, sores in the mouth, rash with blisters on the palm of hands and soles of feet were sent to Enteric Viruses Laboratory of Adolfo Lutz Institute. Clinical samples were inoculated in three different cell lines, and those which presented cytopathic effect (CPE), were submitted to Indirect Immunofluorescence Assay (IFA) and "one step" RT-PCR. Agarose gel electrophoresis from RT-PCR product, showed a product with 437 bp, which is characteristic of Enterovirus group. Echovirus 4 was identified by IFA. Although HFMD is a viral infection associated mainly with Enterovirus 71 (HEV-71) and Coxsackievirus A16 (CV-A16), our results demonstrate a diversity of serotype related to HFMD and stress the importance of epidemiological surveillance to this disease and its complications.

A Doença de Mão, Pé e Boca (DMPB) é uma infecção enteroviral contagiosa que ocorre principalmente em crianças sendo caracterizada por erupções palmoplantares vesiculares e estomatite. Echovirus 4 (EV-4) é comumente associado a meningite asséptica. A associação de DMPB por EV-4 não foi descrita anteriormente. Duas amostras provenientes de uma criança de 14 meses apresentando febre, secreções na garganta e exantemas nas palmas das mãos e dos pés, foram enviadas para o Laboratório de Vírus Entéricos do Instituto Adolfo Lutz. As amostras foram inoculadas em três diferentes linhagens celulares; aquelas que apresentaram efeito citopático (ECP), foram submetidas a ensaio de imunofluorescência indireta (IFI) e "one step" RT-PCR. A eletroforese em gel de agarose realizada com o produto de PCR apresentou um produto de 437pb, característico de grupo Enterovirus. O sorotipo EV-4 foi identificado por IFI. Apesar da DMPB ser uma infecção viral associada principalmente com Enterovirus 71 (HEV-71) e Coxsackievirus A16 (CV-A16), nossos resultados enfatizam a necessidade de estudos epidemiológicos e laboratoriais direcionados ao EV-4 como agente causador de DMPB.