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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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The results of space-time cluster analysis for mild cases of Zhejiang Province, 2008–2012.
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pone.0139109.g006: The results of space-time cluster analysis for mild cases of Zhejiang Province, 2008–2012.

Mentions: Table 5 listed the scanning results of most likely clusters for mild cases derived from the retrospective space-time cluster analysis. The results showed that most likely clusters (dark blue) were mainly located at eastern coastal and southern regions (Fig 6). In 2008, 15 counties were classified into the most likely cluster (radius of the cluster was 93.26 km) from May to June where 7,807 cases were observed with a very high RR of 8.95 (P<0.001). During 2009 to 2012, RR was lowered and ranged from 3.74 to 4.36 while the number of the clusters was almost stable. EV71 was the major causative of the most likely clusters and the proportions of them were much higher than other regions (Table 5) which hinted that EV71 was associated with not only the severity of HFMD but also the clusters of HFMD. The second most likely clusters (light blue) illustrated in Fig 6 spread all over the province, especially those counties from Ningbo, Jinhua, Shaoxing and Quzhou. According to severe cases, the scanning results of most likely clusters were similar to those of spatial autocorrelation association and three districts (Wenzhou, Lishui and Ningbo) were major clusters (S2 Table and S8 Fig).


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)

The results of space-time cluster analysis for mild cases of Zhejiang Province, 2008–2012.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0139109.g006: The results of space-time cluster analysis for mild cases of Zhejiang Province, 2008–2012.
Mentions: Table 5 listed the scanning results of most likely clusters for mild cases derived from the retrospective space-time cluster analysis. The results showed that most likely clusters (dark blue) were mainly located at eastern coastal and southern regions (Fig 6). In 2008, 15 counties were classified into the most likely cluster (radius of the cluster was 93.26 km) from May to June where 7,807 cases were observed with a very high RR of 8.95 (P<0.001). During 2009 to 2012, RR was lowered and ranged from 3.74 to 4.36 while the number of the clusters was almost stable. EV71 was the major causative of the most likely clusters and the proportions of them were much higher than other regions (Table 5) which hinted that EV71 was associated with not only the severity of HFMD but also the clusters of HFMD. The second most likely clusters (light blue) illustrated in Fig 6 spread all over the province, especially those counties from Ningbo, Jinhua, Shaoxing and Quzhou. According to severe cases, the scanning results of most likely clusters were similar to those of spatial autocorrelation association and three districts (Wenzhou, Lishui and Ningbo) were major clusters (S2 Table and S8 Fig).

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