| an outbreak of enzootic bovine leukosis in upper egypt: clinical, laboratory and molecular-epidemiological studies. | in 1989, 220 holstein friesian cattle (212 heifers and eight bulls) were imported from minnesota, usa, to form a closed dairy herd in arab el-aoumar, assiut, upper egypt. in november 1996, some abnormal signs such as loss of weight, decreased milk yield, external lymphadenopathy and decreased appetite were observed on this farm. serological screening by enzyme-linked immunosorbent assay revealed a seroprevalence of antibodies directed against bovine leukaemia virus (blv) of 37.7% in cattle under ... | 2002 | 12019942 |