trend of diseases among iranian pilgrims during five consecutive years based on a syndromic surveillance system in hajj

background: every year more than 2 million people depart from iran to saudi arabia for hajj ritual which can be faced with some different diseases. there are not much information about frequencies and trend of diseases in hajj. the main objective of this study was to determine the trend of prevalent diseases during five consecutive hajj rituals among iranian pilgrims. methods: we established a specific surveillance system for all iranian pilgrims who had participated in hajj from 2004 to 2008. we monitored the pilgrims’ health status before departure, through their journey. the understudied diseases were 19 selected types of diseases in the hajj. the occurrences of diseases were recorded on a researchers-made questionnaire. we used chi-square test for analysis with the alpha lower than 5% to reject the null hypothesis. results: during 5 consecutive periods, a total of 254,823 of iranian pilgrims were monitored for more common diseases 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 frequency of respiratory involvement was lower in 2006 than other years (p < 0.001).there were statistically significant differences between the numbers of hospitalization and patients who were referred back to iran with the year of hajj (p < 0.001). conclusion: health managers should be informed about trend and frequency of more prevalent diseases in hajj. easy access to health information via such surveillance system can be possible.