Trend of diseases among Iranian pilgrims during five consecutive years based on a Syndromic Surveillance System in Hajj

Every year more than 2 million people depart from Iran to Saudi Arabia for Hajj ritual whichcan be faced with some different diseases. There are not much information about frequencies and trend of diseasesin Hajj. The main objective of this study was to determine the trend of prevalent diseases during five consecutiveHajj rituals among Iranian pilgrims. We established a specific surveillance system for all Iranian pilgrims who had participated in Hajjfrom 2004 to 2008. We monitored the pilgrims' health status before departure, through their journey. The understudieddiseases were 19 selected types of diseases in the Hajj. The occurrences of diseases were recorded on aresearchers-made questionnaire. We used chi-square test for analysis with the alpha lower than 5% to reject thenull hypothesis. During 5 consecutive periods, a total of 254,823 of Iranian pilgrims were monitored for more commondiseases with this system. The most prevalent diseases were as follows: at least one type of respiratory involvement(71.26%), common cold like syndrome (47.15%), and musculoskeletal disorders (18.67%), The frequencyof respiratory involvement was lower in 2006 than other years (p