Abstract
BACKGROUND: Leptospirosis, caused by pathogenic Leptospira spp., is an important zoonotic disease that is found globally, with recent outbreaks posing a major public health challenge. This disease affects a wide range of mammalian species. While rodents, dogs, cattle, and buffaloes are recognized reservoirs of Leptospira, the role of swine in transmission in Sri Lanka remains unclear. This study aimed to investigate the carrier status of Leptospira spp. in swine raised for human consumption in Sri Lanka, and to assess potential zoonotic risks. RESULTS: Analysis of livestock data revealed the highest density of pigs in the Gampaha, Colombo, and Puttalam districts. Kidney (n = 181) and blood (n = 25) samples were collected from swine slaughtered for human consumption in the Colombo and Kegalle districts. Leptospiral DNA was detected in 25 of the kidney samples (13.8%), identifying Leptospira interrogans (n = 21), P1 (pathogenic) subclade, and L. licerasiae (n = 4), P2 (intermediate) subclade. Serological analysis revealed seropositivity to the serogroups Autumnalis, Icterohaemorrhagiae, Canicola, and Sejroe. CONCLUSIONS: This study demonstrates that swine reared for human consumption in Sri Lanka serve as an important reservoir of Leptospira spp. All pigs sampled were clinically healthy at ante-mortem inspection, confirming their role as asymptomatic carriers of Leptospira spp. The detection of strains identical to those previously reported in human infections suggests a potential zoonotic threat exacerbated by inadequate farm hygiene and environmental contamination. These findings highlight the need for comprehensive research from a One Health perspective to gain a deeper understanding of the epidemiology of leptospirosis in Sri Lanka.