Outbreak Investigation of officially reported of highly pathogenic avian influenza (H5N8 subtype) in Iran- 2016

Document Type: Original Articles


1 Department of Poultry Diseases, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran

2 Department of Health and Management of Poultry Diseases, Iranian Veterinary Organization, Tehran, Iran

3 Department of Food Hygiene & Quality Control, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran

4 Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran


On 14 November of 2016, an outbreak of HPAI was reported from a commercial layer farm located in Malard, Tehran province. The aim of study was to investigate HPAI H5N8 outbreaks in Iran. The questionnaire was prepared and completed through interviews with farm owners or field observations at the time of disease onset from November 2016 to February 2017. The HPAI H5N8 infection was confirmed in 30 different locations (10 villages (33.3%), nine layer farms (33%), two broiler breeder farms (6.67%), one layer breeder farm (3.3%), one turkey farm (3.3%), one partridge farm (3.3%), five national parks (16.7%), and one wetland (3.3%) in 12 provinces of Iran. The cumulative incidence rates of disease in villages, layer farms, broiler breeder farms, layer breeder farms, partridge farms, and turkey farms were 0.02%, 0.87%, 0.55%, 6.25%, 7.14%, and 0.69%, respectively. The findings reflect that among the investigated variables at infected locations, new birds entering the home in villages, live bird markets, inappropriate biosecurity conditions, transporting manure during the breeding period, close proximity of a common road to infected farms, and poultry movement inside (pullet) and outside were the most frequently observed possible risk factors for these outbreaks.
In conclusion, attention should be focused on the study of the dynamics and movements of domestic poultry; the investigation and modification of the structure of industrial poultry farms; training for all related people; enhancing passive surveillance; increase biosecurity; increasing attention of the authorities on the importance of the infection; and supplying the required credits and facilities.