Epidemiological investigation of waterborne and foodborne disease outbreaks in Iran: 2012-2018

Background and Aim: Understanding the epidemiology of outbreaks of waterborne and foodborne diseases is essential for adopting prevention and control strategies. The purpose of this study was to investigate the reported outbreaks in Iran during 2012-2018. Methods: In this retrospective descriptive study, secondary data extracted from reports of outbreaks of waterborne and foodborne diseases submitted to the Ministry of Health, the Centers for Communicable Disease Control, from 2012 to 2018. Epidemiological trends and aspects of outbreaks were analyzed according to etiologic factors, location of the outbreak, food vehicles, month, year and geographic location. Results: Between 2012 and 2018, 20615 food and waterborne disease outbreaks were reported, resulting in 158650 illnesses, 19664 hospitalizations, and 288 deaths. The cause of the outbreak of waterborne and foodborne illness has been identified in only 40% of cases based on laboratory results. The most common cause was Escherichia coli (30.6%) followed by Shigella (1.8%). Outbreaks most frequently occurred in personal home (69.1%), ceremony (5.8%), and restaurants (4.4%). Conclusion: Although reporting of outbreaks of waterborne and foodborne illnesses has improved in recent years, we are still underreported. There is great variability in outbreaks investigation and reporting throughout the country. This study is based only on reports of outbreaks to the Ministry of Health and does not necessarily indicate the correct burden of outbreaks in the country. Strengthening and training of those involved in the reporting system, including for the collection of epidemiological data and samples, is recommended.