Spatiotemporal patterns and risk factors for African swine fever-affected smallholder pig farms in Davao Region, Southern Philippines

Abstract

African swine fever (ASF) has severely disrupted the Philippine pig industry, necessitating a thorough understanding of its local epidemiology to develop effective mitigation strategies. The outbreak has particularly impacted smallholder farmers, who face substantial economic losses, livelihood threats, and psychological distress due to ASF. This study examined the ASF outbreak in Davao Region, Southern Philippines, by analyzing its spatiotemporal patterns and identifying risk factors. The investigation involved three parts: determining spatiotemporal patterns using spatial autocorrelation and hotspot analysis, conducting Key Informant Interviews (KIIs) with government veterinarians to identify local risk factors, and fitting a conditional logistic regression model to estimate the effects of biosecurity and farming practices on the likelihood of ASF occurrence. A sharp decline in incidence rates and non-recurring hotspots of ASF-affected barangays (villages) were observed, which may have been influenced by community quarantines and 1–7–10 zoning protocols. However, ASF hotspots continuously shifted towards the northeast provinces of the region. Thematic analysis of collected data from KIIs highlighted six general areas of ASF management and control that have posed challenges: farm biosecurity, traders' roles, farmers' capabilities, slaughterhouse practices, veterinary services, and response gaps. Regression analysis revealed that biosecurity measures for trade vehicles and cleaning practices were associated with a decreased likelihood of ASF risk, while swill feeding, inadequate waste management, and improper disposal of diseased pigs were associated with an increased likelihood of ASF risk. These findings provide critical insights for managing ASF spread while supporting smallholder farmers, strengthening the livestock industry’s resilience against similar diseases.