en Epidemiology Epidemiology Original Research Original Research <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span style="font-family:&quot;Times New Roman&quot;,serif"><span style="font-style:italic"><b><span style="font-size:9.0pt"><span style="font-style:normal">Background: </span></span></b><span style="font-size:9.0pt"><span style="font-style:normal">Despite the advances in the control of infectious diseases like cholera, they can potentially cause epidemics, especially in mass gathering events. One of the most important countries on the walking way of the </span></span><span style="font-size:9.0pt">Arbaeen</span><span style="font-size:9.0pt"><span style="font-style:normal"> religious event is Iran, which requires health system preparedness. The aim of this study was to predict the cholera epidemic in Iran by using the syndromic surveillance system of Iranian pilgrims in Iraq.</span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span style="font-family:&quot;Times New Roman&quot;,serif"><span style="font-style:italic"><b><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp;&nbsp; Methods:</span></span></b><span style="font-size:9.0pt"><span style="font-style:normal"> The data of the Iranian pilgrims with acute watery diarrhea in Iraq during the </span></span><span style="font-size:9.0pt">Arbaeen</span><span style="font-size:9.0pt"><span style="font-style:normal"> religious event and the confirmed cholera cases of pilgrims after returning to Iran were analyzed. We used the Poisson regression model of the relationship between the numbers of cases to evaluate acute watery diarrhea and cholera. Spatial statistics and hot spot analysis were used to identify the provinces with the highest incidence. SPSS software Version 24 was used for statistical analysis.</span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span style="font-family:&quot;Times New Roman&quot;,serif"><span style="font-style:italic"><b><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp;&nbsp; Results:</span></span></b><span style="font-size:9.0pt"><span style="font-style:normal"> The frequency of acute watery diarrhea cases was 2232 and the frequency of cholera in pilgrims after returning to Iran was 641. The results of spatial analysis for acute watery diarrhea cases showed a high number of acute watery diarrhea cases in the Khuzestan and Isfahan provinces, located in hot spots. Using Poisson regression, the relationship between the number of acute watery diarrhea reported in the syndromic surveillance system and the number of cholera cases was confirmed.</span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span style="font-family:&quot;Times New Roman&quot;,serif"><span style="font-style:italic"><b><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp;&nbsp; Conclusion:</span></span></b><span style="font-size:9.0pt"><span style="font-style:normal"> The syndromic surveillance system is useful to predict the outbreak of infectious diseases in large religious mass gatherings.</span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span style="font-family:&quot;Times New Roman&quot;,serif"><span style="font-style:italic"><b><span style="font-size:9.0pt"><span style="font-style:normal"></span></span></b></span></span></span></span></span></span><br> &nbsp; Syndromic Surveillance System, Epidemic, Cholera, Early Warning, Early Detection of Epidemics, Arbaeen 455 459 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-7970-1&slc_lang=en&sid=1 Mahbobeh Taheri mahbobeh.taheri64@yahoo.com 200319475328460077554 200319475328460077554 No Department of Community Medicine, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran Babak Eshrati eshratib@sina.tums.ac.ir 200319475328460077555 200319475328460077555 No Preventive Medicine and Public Health Research Center, Iran University of Medical Sciences, Tehran, Iran Ayad Bahadorimonfared 200319475328460077556 200319475328460077556 No Department of Community Medicine, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran Mohammad-Reza Sohrabi m.sohrabi@sbmu.ac.ir 200319475328460077557 200319475328460077557 Yes Department of Community Medicine, School of Medicine, & Social Determinants of Health Research Centre, Shahid Beheshti University of Medical Science, Tehran, Iran