Objective: To understand the temporal-spatial distribution of hand-foot-mouth disease in Zhejiang province, from May 2008 to June 2013.
Methods: The cases number and incidence data of hand-foot-mouth disease from May 2008 to June 2013 for all the counties(cities, districts) in Zhejiang province were collected from China Information System for Disease Control and Prevention, total 511 643 cases. Temporal distribution of hand-foot-mouth disease was described, the incidence maps were drawn using Epimap software. Temporal-spatial clustering was analyzed by Satscan 9.0.1 software.Log likelihood ratio(LLR) was used to assess the clustering. The year-county (city, district)-specific relative risk(RR) of hand-foot-mouth disease were calculated. RR contour maps were drawn with Arcview GIS 3.3.
Results: In Zhejiang province, from May 2008 to June 2013, the highest incidence rate was 270.81/100 000 (147 943/54 629 996) (2012 year) and the lowest incidence rate was 135.32/100 000 (69 285/51 199 987) (2009 year). The incidence in the eastern coastal areas (217.77/100 000(286 300/131 468 746)) including Ningbo, Taizhou, Wenzhou, was higher than the western mountain areas(168.11/100 000(98 016/58 304 266)) including Quzhou, Lishui, Jinhua. The epidemic curve showed two peaks, during April to July (101.15/100 000(320 144/316 497 516)) , and during October to November (23.30/100 000 (61 088/262 148 114)) .
Results: of temporal-spatial scan showed 10 temporal spatial aggregation areas, the strongest one was in Wenzhou city, south-east Zhejiang province, from July 2009 to June 2011(RR = 2.38, LLR = 10 650.75, P < 0.01). The relative risk maps from 2009 to 2012 were similar, the highest density areas were located in the eastern coastal Zhejiang: Longwan district, Wenzhou city (RR = 4.42 and 3.30) in 2009 and 2010 year, Pingyang county, Wenzhou city(RR = 3.04) in 2011 year, and Ninghai county, Ningbo city(RR = 2.97) in 2012.
Conclusion: The eastern coastal area had a high incidence level of hand-foot-mouth disease in Zhejiang province, 2008-2013, with the peak during April to July. Temporal-spatial clustering were observed, the disease showed a distinct regional distribution feature, eastern coastal cluster areas and mid-west cluster areas were found.