Risk Factors Associated with Highly Pathogenic Avian Influenza subtype H5N8 Outbreaks on Broiler Duck Farms in South Korea = Risk Factors Associated with Highly Pathogenic Avian Influenza subtype H5N8 Outbreaks on Broiler Duck Farms in South Korea

다국어 초록 (Multilingual Abstract)

Introduction: Highly Pathogenic Avian Influenza (HPAI) subtype H5N8 outbreaks occurred in poultry farms in South Korea in 2014 resulting in significant damage to the poultry industry. Between 2014 and 2016, the pandemic disease caused significant economic loss and social disruption. To evaluate the risk factors of HPAI infection in broiler duck farms, we conducted a retrospective case-control study on broiler duck farms.
Materials and Methods: Forty-three farms with confirmed laboratories on premises were selected as the case group and 43 HPAI-negative farms were designated as the control group. Control farms were matched based on farm location and were within a 3-km radius from the case premises. Spatial and environmental factors were characterized by site visit and plotted through a geographic information system (GIS). Univariable and multivariable logistic regression models were developed to assess possible risk factors associated with HPAI broiler duck farm infection.
Results: Four final variables were identified as risk factors in a final multivariable logistic model: “Farms with ≥ seven flocks” (odds ratio [OR] = 6.99, 95% confidence interval [CI] 1.34-37.04), “Farm owner with ≥ 15 yrs. of raising poultry career” (OR = 7.91, 95% CI 1.69-37.14), “Presence of any poultry farms located within 500 m of the farm” (OR = 6.30, 95% CI 1.08-36.93), and “Not using a fecal removal service” (OR = 27.78, 95% CI 3.89-198.80).
Conclusion: This highlights that the HPAI H5N8 outbreaks in South Korea were associated with farm owner education, number of flocks and facilities, and farm biosecurity. Awareness of these factors may help reduce the spread of HPAI H5N8 across broiler duck farms in Korea during epidemics. Greater understanding of the risk factors for H5N8 may improve farm vulnerability to HPAI and other subtypes and help establish policies to prevent re-occurrence. These findings are relevant to global prevention recommendations and intervention protocols.
Acknowledgements: This research was supported by Animal Disease Management Technology Development, Ministry for Agriculture, Food and Rural Affairs, Republic of Korea. (314005-2)