Evaluation of enterovirus 71 immune status in São Paulo state, Brazil

Luchs, Adriana; Cilli, Audrey; Russo, Denise; Costa, Fernanda Faria; Carmona, Rita de Cássia Compagnoli; Timenetsky, María do Carmo Sampaio Tavares

doi:10.1590/s0036-46652010000600010

Cited by 3 publications

(2 citation statements)

References 17 publications

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“…In addition to self-limiting HFMD or herpangina, EV-A71 is also rarely associated with more severe neurological diseases such as encephalitis, meningitis, acute flaccid paralysis and neurogenic pulmonary edema [ 6 , 7 ]. Since its first isolation in California in 1969, numerous epidemics of EV-A71 have been reported, mainly in Asia, including Singapore [ 8 , 9 ], Malaysia [ 10 , 11 ], Taiwan [ 12 , 13 ] and mainland China [ 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Cyclical Patterns of Hand, Foot and Mouth Disease Caused by Enterovirus A71 in Malaysia

et al. 2016

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Enterovirus A71 (EV-A71) is an important emerging pathogen causing large epidemics of hand, foot and mouth disease (HFMD) in children. In Malaysia, since the first EV-A71 epidemic in 1997, recurrent cyclical epidemics have occurred every 2–3 years for reasons that remain unclear. We hypothesize that this cyclical pattern is due to changes in population immunity in children (measured as seroprevalence). Neutralizing antibody titers against EV-A71 were measured in 2,141 residual serum samples collected from children ≤12 years old between 1995 and 2012 to determine the seroprevalence of EV-A71. Reported national HFMD incidence was highest in children <2 years, and decreased with age; in support of this, EV-A71 seroprevalence was significantly associated with age, indicating greater susceptibility in younger children. EV-A71 epidemics are also characterized by peaks of increased genetic diversity, often with genotype changes. Cross-sectional time series analysis was used to model the association between EV-A71 epidemic periods and EV-A71 seroprevalence adjusting for age and climatic variables (temperature, rainfall, rain days and ultraviolet radiance). A 10% increase in absolute monthly EV-A71 seroprevalence was associated with a 45% higher odds of an epidemic (adjusted odds ratio, aOR1.45; 95% CI 1.24–1.69; P<0.001). Every 10% decrease in seroprevalence between preceding and current months was associated with a 16% higher odds of an epidemic (aOR = 1.16; CI 1.01–1.34 P<0.034). In summary, the 2–3 year cyclical pattern of EV-A71 epidemics in Malaysia is mainly due to the fall of population immunity accompanying the accumulation of susceptible children between epidemics. This study will impact the future planning, timing and target populations for vaccine programs.

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Section: Introductionmentioning

confidence: 99%

Cyclical Patterns of Hand, Foot and Mouth Disease Caused by Enterovirus A71 in Malaysia

et al. 2016

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“…Seroprevalence rates of enterovirus A71 (EV‐A71) infection in different age groups worldwide . The data of 26 studies were collected according to their age groups and geographic locations and represented by a green‐yellow‐red colour heatmap.…”

Section: Ev‐a71 Infection Is Common: Evidence From Seroepidemiology Smentioning

confidence: 99%

Immune responses against enterovirus A71 infection: Implications for vaccine success

Aw-Yong

NikNadia

Tan

et al. 2019

Reviews in Medical Virology

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Summary Enterovirus A71 (EV‐A71) from the Picornaviridae family is an important emerging pathogen causing hand, foot, and mouth disease (HFMD) outbreaks worldwide. EV‐A71 also caused fatal neurological complications in young children especially in Asia. On the basis of seroepidemiological studies from many Asian countries, EV‐A71 infection is very common. Children of very young age are particularly vulnerable. Large‐scale epidemics that occur every 3 to 4 years are associated with accumulation of an immunologically naive younger population. Capsid proteins especially VP1 with the presence of major B‐ and T‐cell epitopes are the most antigenic proteins. The nonstructural proteins mainly contribute to T‐cell epitopes that induce cross‐reactive immune responses against other enteroviruses. Dominant epitopes and their neutralization magnitudes differ in mice, rabbits, and humans. Neutralizing antibody is sufficient for immune protection, but poorer cellular immunity may lead to severe neurological complications and deaths. Some chemokines/cytokines are consistently found in severely ill patients, for example, IL‐6, IL‐10, IL‐17A, MCP‐1, IL‐8, MIG, IP‐10, IFN‐γ, and G‐CSF. An increase in white cell counts is a risk factor for severe HFMD. Recent clinical trials on EV‐A71 inactivated vaccine showed >90% efficacy and a robust neutralization response that was protective, indicating neutralizing antibody correlates for protection. No protection against other enteroviruses was observed. A comprehensive understanding of the immune responses to EV‐A71 infection will benefit the development of diagnostic tools, potential therapeutics, and subunit vaccine candidates. Future development of a multivalent enterovirus vaccine will require knowledge of correlates of protection, understanding of cross‐protection and memory T‐cell responses among enteroviruses.

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Epidemiological Characteristics and Spatial-Temporal Clusters of Hand, Foot, and Mouth Disease in Zhejiang Province, China, 2008-2012

et al. 2015

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Hand, foot and mouth disease (HFMD) is one of the major public health concerns in China. Being the province with high incidence rates of HFMD, the epidemiological features and the spatial-temporal patterns of Zhejiang Province were still unknown. The objective of this study was to investigate the epidemiological characteristics and the high-incidence clusters, as well as explore some potential risk factors. The surveillance data of HFMD during 2008–2012 were collected from the communicable disease surveillance network system of Zhejiang Provincial Center for Disease Control and Prevention. The distributions of age, gender, occupation, season, region, pathogen’s serotype and disease severity were analyzed to describe the epidemiological features of HFMD in Zhejiang Province. Seroprevalence survey for human enterovirus 71 (EV71) in 549 healthy children of Zhejiang Province was also performed, as well as 27 seroprevalence publications between 1997 and 2015 were summarized. The spatial-temporal methods were performed to explore the clusters at county level. Furthermore, pathogens’ serotypes such as EV71 and coxsackievirus A16 (Cox A16) and meteorological factors were analyzed to explore the potential factors associated with the clusters. A total of 454,339 HFMD cases were reported in Zhejiang Province during 2008–2012, including 1688 (0.37%) severe cases. The annual average incidence rate was 172.98 per 100,000 (ranged from 72.61 to 270.04). The male-to-female ratio for mild cases was around 1.64:1, and up to 1.87:1 for severe cases. Of the total cases, children aged under three years old and under five years old accounted for almost 60% and 90%, respectively. Among all enteroviruses, the predominant serotype was EV71 (49.70%), followed by Cox A16 (26.05%) and other enteroviruses (24.24%) for mild cases. In severe cases, EV71 (82.85%) was the major causative agent. EV71 seroprevalence survey in healthy children confirmed that occult infection was common in children. Furthermore, literature summary for 26 seroprevalence studies during 1997–2015 confirmed that 0–5 years group showed lowest level of EV71 seroprevalence (29.1% on average) compared to the elder children (6–10 years group: 54.6%; 11–20 years group: 61.8%). Global positive spatial autocorrelation patterns (Moran’s Is>0.25, P<0.05) were discovered not only for mild cases but also for severe cases, and local positive spatial autocorrelation patterns were revealed for counties from the eastern coastal and southern regions. The retrospective space-time cluster analysis also confirmed these patterns. Risk factors analyses implied that more EV71 and less sunshine were associated with the clusters of HFMD in Zhejiang Province. Our study confirmed that Zhejiang Province was one of the highly epidemic provinces in China and that the epidemiological characteristics of HFMD were similar to other provinces. Occult infection in elder children and adults was one of the important reasons why most HFMD cases were children aged under-five. Combining the results of spatial a...

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Evaluation of enterovirus 71 immune status in São Paulo state, Brazil

Cited by 3 publications

References 17 publications

Cyclical Patterns of Hand, Foot and Mouth Disease Caused by Enterovirus A71 in Malaysia

Cyclical Patterns of Hand, Foot and Mouth Disease Caused by Enterovirus A71 in Malaysia

Immune responses against enterovirus A71 infection: Implications for vaccine success

Epidemiological Characteristics and Spatial-Temporal Clusters of Hand, Foot, and Mouth Disease in Zhejiang Province, China, 2008-2012

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