The circular distribution analysis on peak changes of hand-foot-mouth disease in Zhoushan City / 预防医学

ABSTRACT

Objective Todescribethemonthlyincidencedistributionofhand-foot-mouthdisease(HFMD)from2010to 2012inZhoushancityandtoanalyzetheseasonaltrendandthecausesofpeakchanges.Methods Circulardistribution method was used to identify the peak period of HFMD incidence.Watson -William test and Watson's U2 test were applied for comparing the peak periods respectively.Chi -square test was conducted to analyze and compare the distribution of HFMDpathogenindifferentyearsandBonferronimethodwasusedformultiplecomparisons.Results Therewasseasonal centralized tendency of HFMD incidence during 2010 to 2012 (P<0.01).The peak period occurred between 8th of May and 1st of September which showed a significant difference among three years (P<0.01).Specifically,the peak period in 2012 was earlier than that in 2010 and 201 1 (both P<0.01 ).Among the 356 reported cases with laboratory confirmed, there was significant difference between the distribution of HFMD pathogen by Chi -square test (P <0.01 ).The predominant strain was EV71 in 2010 and 2011 accounting for 58.46%and 64.62%respectively and other enteric viruses in 2012 accounting for 48.84%.The ratio of pathogens in 2012 was statistically different from that in 2010 and 201 1 respectively(bothP<0.01).Conclusion HFMDcasesoccurwithobviouspeakseason,regionalandgeographic differences.The major pathogens of EV71 in 2010 and 2011 were changed into other enteric viruses in 2012.