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

Gui J, Liu Z, Zhang T, Hua Q, Jiang Z, Chen B, Gu H, Lv H, Dong C - PLoS ONE (2015)

Bottom Line: 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%).Risk factors analyses implied that more EV71 and less sunshine were associated with the clusters of HFMD in Zhejiang Province.Combining the results of spatial autocorrelation analysis and the space-time cluster analysis, the major spatial-temporal clusters were from the eastern coastal and southern regions.

View Article: PubMed Central - PubMed

Affiliation: Zhejiang Provincial Key Laboratory of Pathophysiology, Department of Preventive Medicine, Ningbo University School of Medicine, Ningbo, Zhejiang Province, China.

ABSTRACT
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 autocorrelation analysis and the space-time cluster analysis, the major spatial-temporal clusters were from the eastern coastal and southern regions. The distribution of pathogens' serotypes and the level of sunshine could be risk factors for, and serve as an early warning of, the outbreak of HFMD in Zhejiang Province.

No MeSH data available.


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Age-specific EV71 seroprevalence summary in healthy children.
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pone.0139109.g005: Age-specific EV71 seroprevalence summary in healthy children.

Mentions: Among 26 seroprevalence studies (pre- and post-epidemic studies were performed in four publications) during 1997–2015, two-thirds were surveyed in mainland China and Taiwan (Table 3). Almost all studies used neutralizing antibody to test serum antibodies except for our and Kuang et al.’s studies where EV71-IgG was detected by ELISA. Only four studies were based on neonates (0 year) and cord blood was used instead of venous blood. The neonates exhibited high seroprevalence (44.0–75.0%) which implied that their mothers (the source of the neonates’ antibodies) had high level of EV71 antibody. In general, the level of the neonates’ antibodies declined until six months after birth when occult infection could induce the active immunity. Therefore, 0–5 years group (children aged under-five) showed lowest level of EV71 seroprevalence (29.1% on average, Table 3 and Fig 5). Since the elder children had more chances of exposure to the enteroviruses and repeated active immunity, their seorprevalences were significant higher than the younger (6–10 years group: 54.6%, t = 4.540, P<0.001; 11–20 years group: 61.8%, t = 6.406, P<0.001). This age-specific EV71 seroprevalence pattern provided the evidence that children aged under-five were most susceptible to HFMD. Another hypothesis was that HFMD epidemics would significantly increase the level of EV71 seroprevalence after the epidemics. However, the results of four studies were contradictory (Table 3): one positive result (Study ID: 9&10) and three mixed results (Study ID: 5&6, 15&16, 17&18). Furthermore, as a country confronting the long-term exposure to HFMD epidemics, it was considered that China may have a higher level of seroprevalence than other counties. Fig 5 indicated that only 0–5 years group exhibited significant difference between China and other counties (t = 2.694, P = 0.013) which implied the complex relationship between the seroprevalence and the history of exposure.


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

Gui J, Liu Z, Zhang T, Hua Q, Jiang Z, Chen B, Gu H, Lv H, Dong C - PLoS ONE (2015)

Age-specific EV71 seroprevalence summary in healthy children.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4589370&req=5

pone.0139109.g005: Age-specific EV71 seroprevalence summary in healthy children.
Mentions: Among 26 seroprevalence studies (pre- and post-epidemic studies were performed in four publications) during 1997–2015, two-thirds were surveyed in mainland China and Taiwan (Table 3). Almost all studies used neutralizing antibody to test serum antibodies except for our and Kuang et al.’s studies where EV71-IgG was detected by ELISA. Only four studies were based on neonates (0 year) and cord blood was used instead of venous blood. The neonates exhibited high seroprevalence (44.0–75.0%) which implied that their mothers (the source of the neonates’ antibodies) had high level of EV71 antibody. In general, the level of the neonates’ antibodies declined until six months after birth when occult infection could induce the active immunity. Therefore, 0–5 years group (children aged under-five) showed lowest level of EV71 seroprevalence (29.1% on average, Table 3 and Fig 5). Since the elder children had more chances of exposure to the enteroviruses and repeated active immunity, their seorprevalences were significant higher than the younger (6–10 years group: 54.6%, t = 4.540, P<0.001; 11–20 years group: 61.8%, t = 6.406, P<0.001). This age-specific EV71 seroprevalence pattern provided the evidence that children aged under-five were most susceptible to HFMD. Another hypothesis was that HFMD epidemics would significantly increase the level of EV71 seroprevalence after the epidemics. However, the results of four studies were contradictory (Table 3): one positive result (Study ID: 9&10) and three mixed results (Study ID: 5&6, 15&16, 17&18). Furthermore, as a country confronting the long-term exposure to HFMD epidemics, it was considered that China may have a higher level of seroprevalence than other counties. Fig 5 indicated that only 0–5 years group exhibited significant difference between China and other counties (t = 2.694, P = 0.013) which implied the complex relationship between the seroprevalence and the history of exposure.

Bottom Line: 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%).Risk factors analyses implied that more EV71 and less sunshine were associated with the clusters of HFMD in Zhejiang Province.Combining the results of spatial autocorrelation analysis and the space-time cluster analysis, the major spatial-temporal clusters were from the eastern coastal and southern regions.

View Article: PubMed Central - PubMed

Affiliation: Zhejiang Provincial Key Laboratory of Pathophysiology, Department of Preventive Medicine, Ningbo University School of Medicine, Ningbo, Zhejiang Province, China.

ABSTRACT
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 autocorrelation analysis and the space-time cluster analysis, the major spatial-temporal clusters were from the eastern coastal and southern regions. The distribution of pathogens' serotypes and the level of sunshine could be risk factors for, and serve as an early warning of, the outbreak of HFMD in Zhejiang Province.

No MeSH data available.


Related in: MedlinePlus