Surveillance and Management Strategies for African Swine Fever (ASF) in Central Luzon, Philippines

Abstract

African swine fever (ASF) remains a major threat to swine production in Central Luzon, Philippines. This study assessed ASF detection and farm-level risk factors in Central Luzon using a risk-based surveillance framework. Pooled blood samples from five pigs per farm were collected in 277 farms across seven provinces and tested by real-time PCR. The analysis yielded an apparent farm-level prevalence of 26.7% (95% CI: 21.6-32.3), defined by one pooled 5-pig blood sample per farm. However, these values reflect risk-based surveillance outcomes rather than population-representative prevalence. Detection varied by province, with high rates in Bataan (80.5%) and Nueva Ecija (55.0%), moderate detection in Zambales (24.3%), lower detection in Pampanga (5.0%) and Tarlac (20.0%), and no positives in Aurora or Bulacan. Survey data were available for 201 farms. Firth-penalized logistic regression identified the absence of perimeter fencing as the only statistically significant predictor of ASFV detection. Veterinary oversight and consultancy showed protective but non-significant trends. These results highlight structural and professional biosecurity gaps, emphasizing the need for expanded veterinary outreach, fencing support, and training to mitigate ASF risk in smallholder-dominated production systems.

Keywords: African swine fever; Central Luzon Philippines; diagnostics.

Figure 1

Geographic distribution of swine farms included in ASF surveillance across seven provinces of Central Luzon. Red circles = ASFV-positive farms; green circles = ASFV-negative farms. Blue shading indicates municipalities covered by surveillance. Mapping was performed in QGIS version 3.22.10.