Epidemiological characteristics and spatial-temporal cluster analysis of severe hand-foot-mouth disease in Hebei Province, 2010-2015

Abstract

Objective To understand the epidemic characteristics and spatial-temporal clustering of hand-foot-mouth disease (HFMD) in Hebei Province from 2010 to 2015. Methods Surveillance data of severe HFMD cases for each county from 2010 to 2015 in Hebei Province were collected to describe the epidemiological characteristics. Besides, the spatial autocorrelation and potential spatial-temporal clusters were detected using software GeoDa 1.8.10 and SaTScanTM 9.4.2, respectively. Finally, we used ArcGIS 10.2 to draw the thematic maps and visualize the results. Results From 2010 to 2015, there were 3 641 severe HFMD cases were notified with an annual incidence rate of 0.85/105 and the highest incidence of the year was seen in 2010, as 2.49/105, presenting an epidemic phenomena of peaking every other year. There was an obvious temporal distribution of the cases, the main peak occurred in 5 to 7 months. Fluctuation of the epidemics showed a declining trend. The thematic maps of case-severity dot density distribution and the result of spatial autocorrelation analysis all showed that case-severity rates were significantly different and had an obvious regional clusters (Moran's I>0, P<0.05). Local indicators of spatial association (LISA) revealed that High-high clusters were mainly distributed in the central and southern part of Hebei Province, which varied from year to year. Spatial-temporal analysis identified that the most likely cluster was located in Xingtai area (20 counties around Longrao, Radius=60.96km), southern part of Hebei Province (RR=38.08,LLR=1267.00, P<0.001). The other four clusters were detected in the Southwest (14 counties around Shijiazhuang, RR=12.35), central (16 counties around Cangzhou, RR=11.35, 8 counties around Langfang, RR=44.04) and northern (17 counties around Chengde, RR=10.32) part of Hebei Province during May-August during 2010-2012. The case-severity rate of HFMD had a significant decrease from 2013 to 2015 and the clustering of low incidence areas were most likely in Tangshan, Handan, Zhangjiakou and Baoding (RR<1). Moreover, the dominant pathogen was still EV71 among 2207 (60.62%) severe cases, which were confirmed by laboratory testing. Conclusions The appeared spatial-temporal clusters of severe HFMD in Hebei from 2010 to 2015 and high incidence gathering area mainly distributed in the central and southern areas of Hebei province. However, the epidemic showed a declining trend. Key words: Severe hand-food-mouth disease; Epidemiological characteristics; Temporal-spatial clustering