Prevalence of leptospirosis in vaccinated working dogs and humans with occupational risk

Introduction: Working dogs have been identified as a risk group for developing leptospirosis because they can be infected by Leptospira spp., which can be kept in the renal tubules and interstices for a long time, making them carriers and sources of infection for other hosts, including humans. Objective: To establish the prevalence of Leptospira spp. in vaccinated working dogs and in the occupationally exposed population in six police units in Colombia. Materials and methods: A total of 92 vaccinated dogs (65 males and 27 females) and 69 people from six police units in the municipalities of Manizales, Pereira, Armenia, Ibagué, Tuluá, and Cali were tested. Three structured instruments were applied and blood samples were obtained from people and dogs, which were processed with the microagglutination test (MAT) in 24 serogroups. A clinical examination of the dogs was performed and urine samples were obtained for urine cultures. Results: The seroprevalence of human leptospirosis was 2.9% (n=2) and in dogs, it was 57.61% (n=53). Among the dogs, serogroups L. canicola and L. panama were the most prevalent. Urine cultures were positive in 58.7% (54/92) of the samples. A statistically significant association was found between the age of the dogs (≥10 years; p=0.043) and the location of the police unit (p=0.016) with the urine culture. Conclusion: The epidemiological characteristics of leptospirosis in dogs suggest an endemic presentation of the infection. There is an urgent need to improve current diagnostic methods to investigate canine leptospirosis and differentiate between vaccine and natural infection antibodies.