Sero-diagnostic studies on the occurrence and prevalence of bovine spongiform encephalopathies in Nasarawa state, Nigeria

The study was conducted to determine the occurrence and the prevalence of bovine spongiform encephalopathy among cattle herds in Nasarawa State, Nigeria using targeted sampling approach. The procedure of sampling adapted was a “double” targeted method for survey. First, a BSE risk group was targeted ‘emergency or casualty slaughter’ and within this Group, animals with signs indicative for BSE were sub-targeted. Two sampling locations were chosen; Akwanga central abattoir and Lafia central abattoir, both located in Nasarawa North and Nasarawa south senatorial district. Immediately the suspected animals were slaughtered, the caudal brain stem was harvested and examined for the disease specific form of the prion protein, PrPSc, using Western Blot technique after proteinase K digestion. A total of 2000 cattle of local breeds, aged ≥ 24 months and above were clinically examined. A total of 147 (7.4 %) of the cattle sampled were clinically suspicious for BSE. No sample was positive for BSE. Fluorescent antibody test for rabies and H&E staining on samples were carried out to observe for differential diagnosis. These showed no pathological lesions indicative for neurological disease. While our findings do not exclude the presence of BSE in Nasarawa State, we demonstrate that targeted sampling of ruminants for neuroinfectious disease is possible in developing countries, pointing to the possibility of implementing such a monitoring scheme in Nigeria to prevent economic losses in ruminant livestock as BSE caveats from endemic countries have shown.