Leptospira in Working Horses From Rural Ecuador: A Neglected Occupational Risk

Neglected tropical zoonotic diseases such as leptospirosis continue to have a significant impact on animal and human health, especially in low-income countries due to limitations in surveillance and knowledge gaps to guide mitigation. In this context, equines have the potential to play an important role in the maintenance and transmission of Leptospira spp. due to their susceptibility to a variety of serovars (often without signs of disease) and close contact with humans. To better understand the epidemiological role of horses, we evaluated exposure and identified circulating leptospires by collecting blood and urine samples from 13 horses used on agricultural and livestock work in the rural areas of La Concordia and Mompiche, located near the coast of Ecuador. Microscopic agglutination tests showed anti-leptospira antibodies for a variety of serotypes in 100% of 9 serum samples analyzed and pathogenic Leptospira DNA from L. interrogans and L. santarosai in 61.5% of 13 urine samples. These results indicate that exposure of horses to Leptospira is common, and a substantial proportion may actively excrete the pathogen without showing signs of disease. While the small sample size and single time point limit definitive conclusions, in areas where horses interact closely with humans and other animals, these findings suggest that horses could play a role in local environmental cycling of Leptospira. Our findings emphasize the need to strengthen preventive measures in both veterinary and public health areas based on hygiene and sanitary practices that are aligned with a One Health approach.