title: Early detection of an epidemic erythromelalgia outbreak using Baidu search data.
abstract: Dozens of epidemic erythromelalgia (EM) outbreaks have been reported in China since the mid-twentieth century, and the most recent happened in Foshan City, Guangdong Province early 2014. This study compared the daily case counts of this recent epidemic EM outbreak from February 11 to March 3 with Baidu search data for the same period. After keyword selection, filtering and composition, the most correlated lag of the EM Search Index was used for comparison and linear regression model development. This study also explored the spatial distribution of epidemic EM in China during this period based on EM Search Index. The EM Search Index at lag 2 was most significantly associated with daily case counts in Foshan (ρ = 0.863, P < 0.001). It captured an upward trend in the outbreak about one week ahead of official report and the linear regression analysis indicated that every 1.071 increase in the EM Search Index reflected a rise of 1 EM cases 2 days earlier. The spatial analysis found that the number of EM Search Indexes increased in the middle of Guangdong Province and South China during the outbreak period. The EM Search Index may be a good early indicator of an epidemic EM outbreak.
authors.affiliation: Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China.
authors.forename: Yuzhou
authors.initials: Y
authors.lastname: Gu
authors.affiliation: Chancheng Prefectural Center for Disease Control and Prevention of Guangdong Province, Foshan, China.
authors.forename: Fengling
authors.initials: F
authors.lastname: Chen
authors.affiliation: Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.affiliation: Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Lv
authors.affiliation: Chancheng Prefectural Center for Disease Control and Prevention of Guangdong Province, Foshan, China.
authors.forename: Zhaoming
authors.initials: Z
authors.lastname: Shao
authors.affiliation: Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China.
authors.forename: Hualiang
authors.initials: H
authors.lastname: Lin
authors.affiliation: Chancheng Prefectural Center for Disease Control and Prevention of Guangdong Province, Foshan, China.
authors.forename: Chaobin
authors.initials: C
authors.lastname: Liang
authors.affiliation: Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China.
authors.forename: Weilin
authors.initials: W
authors.lastname: Zeng
authors.affiliation: Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China.
authors.forename: Jianpeng
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China.
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Public Health School of Sun Yat-sen University, Guangzhou, China.
authors.forename: Cunrui
authors.initials: C
authors.lastname: Huang
authors.affiliation: Center for Environment and Population Health, School of Environment, Griffith University, Brisbane, Australia.
authors.forename: Shannon
authors.initials: S
authors.lastname: Rutherford
authors.affiliation: Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Ma
mesh_terms: D044466:Asian People; D002681:China / Q000453:epidemiology; D057225:Data Mining / Q000379:methods*; D004196:Disease Outbreaks; D042241:Early Diagnosis; D058872:Epidemics; D004916:Erythromelalgia / Q000175:diagnosis / Q000453:epidemiology* / Q000208:ethnology; D005843:Geography; D006801:Humans; D016014:Linear Models; D011159:Population Surveillance / Q000379:methods*; D015203:Reproducibility of Results