Characterization of biosecurity practices and viral infections on pig farms in Hong Kong

The objectives of this study were to characterize the biosecurity practices implemented on pig farms in Hong Kong and determine the between-farm prevalence of economically important viral pathogens. All active pig farms in Hong Kong (n = 40) were invited to participate in an interview-based survey using a Biocheck-UGent™ questionnaire to evaluate their biosecurity practices. Pen-level oral fluid samples were collected by cotton ropes to detect six target viral pathogens using RT-PCR: porcine reproductive and respiratory virus (PRRSV), porcine circovirus type-2 (PCV-2), swine influenza virus (SIV), porcine delta-coronavirus (PDCoV), porcine epidemic diarrhea virus (PEDV), and transmissible gastroenteritis virus (TGEV). Eighteen farms (45 %) accepted our invitation and participated in this study. Biosecurity practices were found to be inadequate in many areas, with an average overall score of 50.1 ± 9.4 (mean ± SD). The study farms scored higher for external biosecurity (56.4 ± 8.6) than internal biosecurity practices (43.9 ± 12.1). Among external biosecurity subcategories, breeding pig and semen purchase scored highest (93.2), while visitors and farmworkers scored lowest (23.5). In internal biosecurity, the disease management subcategory received the highest score (66.7). Only two external biosecurity subcategories, breeding pig and semen purchase (93.2), and farm location (70) exceeded the global average scores. Key deficiencies were identified in biosecurity protocols for visitors and workers, hygiene standards for feed, water, and equipment supplies, and measures to prevent disease transmission between compartments (farrowing, nursery, and finishing units). Over 90 % of participating farms implemented vaccination programs for PRRSV, PCV-2, porcine parvovirus (PPV), pseudorabies virus (PRV), and classical swine fever virus (CSFV) while no farms vaccinated against SIV, and vaccination for swine coronaviruses was sporadic. All target viruses except TGEV were detected at the farm level. The between-farm prevalences among the 18 study farms were PRRSV-2 (94.4 %), PRRSV-1 (38.9 %), PCV-2 (83.3 %), SIV (55.6 %), PDCoV (16.7 %), and PEDV (5.6 %). We provided comprehensive baseline information on the biosecurity practices of pig farms for the first time in Hong Kong. We identified critical areas of biosecurity for improvement and offered tailored recommendations to help the producers implement more effective prevention and control strategies for infectious diseases within and between farms.