Leptospira Seroprevalence in Colombian Dairy Herds

SIMPLE SUMMARY: Leptospirosis is one of the waterborne diseases whose spread could be significantly affected by global changes that act on the environment, both in Latin America and in other parts of the world. However, there are few studies regarding leptospirosis in cattle from Latin America, especially from Colombia. The aim of the present study was to determine the overall and within-herd seroprevalence and mapping of different Leptospira serovars in dairy cattle from farms located in some municipalities of the Colombian department of Boyacá. A high proportion (95%) of herds with at least one seropositive animal was found. Moreover, within-herd seroprevalence was very high in 20% of the herds. The frequent presence of other domestic animals on farms could be a risk factor for the spread of the infection. Human leptospirosis seroprevalence in some areas of Colombia is high. However, we found that the most common serotypes involved in human disease were the ones with the lowest seroprevalences in cattle in the investigated area. This suggests that cattle could represent a minor risk factor for the transmission of Leptospira infection to humans. Nevertheless, the need for stricter preventive measures in cattle farms has emerged. ABSTRACT: Leptospirosis in cattle has important economic effects on the infected farms. Moreover, livestock farming is considered a major occupational risk factor for the transmission of Leptospira infection to humans. A survey was performed to determine the overall and within-herd seroprevalence and mapping of different Leptospira serovars in dairy cattle from farms located in some municipalities of the Colombian department of Boyacá. Nine hundred and fifty-nine animals, from 20 unvaccinated and one vaccinated herd, were included in the study. Anti-Leptospira serum antibodies were detected by the microscopic agglutination test (MAT). Only one herd was seronegative. Overall seroprevalence to at least one serovar of Leptospira was 24.1% for unvaccinated animals and 62.3% for animals from the vaccinated herd. A very high within-herd seroprevalence (>60%) was present in 20% of the unvaccinated herds. The presence in the vaccinated herd of 20/398 animals showing high titers, between 1000 and 4000, to at least one serovar of Leptospira suggest that some animals could have been infected. Moreover, due to the presence of seronegative animals, a failure of vaccination immunity or the presence of unvaccinated animals in the vaccinated herd cannot be excluded. In all farms, domestic animals other than cattle were present. Considering the farming practices occurring on dairy farms in the study area, higher hygienic standards and stricter biosecurity measures are suggested.