Development and application of a qPCR assay for Lawsonia intracellularis in Tibetan pigs

This study developed a rapid, sensitive, and specific TaqMan MGB based qPCR assay for detecting <i>Lawsonia intracellularis</i> in Tibetan pigs by targeting the <i>aspA</i> gene. The method showed no cross-reactivity with other common porcine enteric pathogens, and exhibited high sensitivity (detection limit: 7.056 copies/μL) and excellent repeatability (CV < 2%). A standard curve with good linearity (R² = 0.998) and 110.95% amplification efficiency was established. The assay was applied to 237 fecal samples collected from Tibetan pigs across eight townships in Xiangcheng County, Sichuan Province, in parallel with a national standard method. Results indicated a 19% overall positivity rate (45/237), with regional rates ranging from 11.11% to 26.67%. The established qPCR provides a reliable tool for field surveillance, and findings underscore the need to integrate <i>L. intracellularis</i> monitoring into local prevention systems to support healthy Tibetan pig production.