Sero-molecular epidemiological analysis of leptospirosis in smallholder dairy cattle in selected regions of Tanzania

Abstract

The smallholder dairy industry in Tanzania is a promising sector for household income generation despite challenges of zoonosis such as leptospirosis caused by Leptospira serovar Hardjo. A total of 2086 blood, serum and additional vaginal swab for female cattle were collected from smallholder dairy cattle for leptospirosis testing using three complementary tests An overall prevalence of 13%, 13.1% and 13.7% for Leptospira serovar Hardjo by ELISA test, RT-PCR for pathogenic Leptospira spp. and MAT respectively. Based on ELISA test, the highest prevalence shown in Iringa 30.2% (95% CI 25.1 - 35.7%) and Tanga 18.9% (95% CI 15.7 - 22.6). In multivariable analysis, factors that were a significant risk in smallholder dairy cattle are: animals over 5 years of age OR = 1.41 (95% CI 1.05 - 1.90); indigenous breed OR = 2.78 (95% CI 1.47 - 5.26); hiring or keeping a bull for breeding purposes OR = 1.91 (95% CI 1.34 - 2.71); distance between farms of more than 100 meters OR = 1.75 (95% CI 1.16 - 2.64); livestock kept extensively (OR = 2.31, 95% CI 1.36 - 3.91); farms without cat for rodent control (OR = 1.87, 95% CI 1.16 - 3.02); farmers with livestock training OR = 1.62 (95% CI 1.15 - 2.27); temperature (OR = 1.63, 95% CI 1.18 - 2.26), and the interaction of higher temperature and precipitation (OR = 1.5, 95%CI 1.12 - 2.01). This findings provide an opportunity for future study to include a broad serogroups panel for more identification of common serogroups circulating in cattle for vaccine target in Tanzanian cattle population.