Serological Survey of Leptospira spp. in Livestock and Rodents from Different Settlements in the Kilombero Wetland, Tanzania

Abstract

Background: The circulation of Leptospira has been linked to various occupational activities globally. This study investigated the seroprevalence of Leptospira spp. in rodents and livestock (cattle and goats) in three settlements/villages involved in agriculture, livestock keeping, and mixed agriculture and livestock in the Kilombero district, Tanzania. Methods: Data were collected during the wet and dry seasons. A total of 179 rodents were live-captured from selected habitats. Livestock samples were collected from 80 cattle in a livestock settlement and 120 goats from both livestock and mixed agricultural–livestock settlements. The microscopic agglutination test was utilized to identify Leptospira serovars. Results: The seroprevalence of Leptospira spp. was 17.3% in rodents (21.7% in Mastomys natalensis and 3.9% in Rattus rattus) and 8.3% in livestock (13.5% in cattle and 12.6% in goats). The prevalence among rodents and livestock differed between settlements (p = 0.01). A higher prevalence was observed among rodents in the agricultural settlement relative to the other settlements. A higher prevalence of antibodies in livestock was observed in the livestock settlement compared with the mixed agricultural–livestock settlement. The Leptospira serovars Sokoine (serogroup Icterohaemorrhagiae) and Hebdomadis (serogroup Hebdomadis) were detected in both rodents and livestock. The serovars Hardjo (serogroup Sejroe) and Gripothyphosa (serogroup Gripothyphosa) were found exclusively in cattle, whereas the serovars Pomona (serogroup Pomona) and Lora (serogroup Australis) were identified in rodents. Leptospira antibodies were found to be elevated during the rainy season compared with the dry season (p = 0.05) in all settlements, with the exception of rodents in the mixed agricultural–livestock settlement. Conclusions: This study demonstrates the presence of anti-Leptospira antibodies in rodents and livestock related to occupational activities in human settlements. It further demonstrates that wild animals (rodents) and livestock are reservoirs of Leptospira and are important in the epidemiology of leptospirosis. Management and control strategies should target both rodents and livestock.