Cross-sectional prevalence of Fasciola gigantica infections in beef cattle in Botswana.

Abstract

A cross-sectional study was carried out to determine the prevalence and distribution of Fasciola gigantica infections in communally grazed and ranch-grazed beef cattle through coprological examination. A total of 8646 cattle (4618 adults, 2843 weaners and 1185 calves) faecal samples were collected during the 24months of study. Results from this study indicated that only 64 (0.74%; 95% CI 0.57, 0.94%) of the samples were positive for F. gigantica eggs. The positive samples were detected in one (Central) of the six study districts and was restricted to the Tuli Block (commercial) farms in Machaneng village in eastern Botswana. The prevalence of fluke eggs was significantly higher in adult cattle (12.85%; 95% CI 9.72, 16.54%) than weaners (6.49%; 95% CI 3.40, 11.06%) and calves (0.79%; 95% CI 0.02, 4.31%), (χ2(2) = 19.01, p < 0.001). Thus, adults (OR = 18.57; 95% CI 2.54, 135.81%) were approximately 20 times more likely to be infected than calves. By taking liver inspection as a gold standard for diagnosis of fasciolosis, the sensitivity of the sedimentation technique was found to be 72.41% and the specificity 100%, with moderate relationship (κ = 0.53; 95% CI 0.31-0.75) between the two methods. This study has demonstrated that infection of cattle from Botswana, with F. gigantica, was low and distribution of the fluke appeared to be linked to suitable environmental conditions for the intermediate host snail. However, detailed surveillance studies, involving more cattle and areas, are required to verify the true prevalence. Such information would assist in the design of appropriate, strategic and effective fluke control programmes.