An Outbreak of Enzootic Bovine Leukosis in Upper Egypt: Clinical, Laboratory and Molecular-Epidemiological Studies

• Published in: Journal of veterinary medicine. Series B Vol. 49; no. 3; pp. 123 - 129
• Main Authors: ZAGHAWA, A., BEIER, D., ABD EL-RAHIM, I. H. A., EL-BALLAL, S., KARIM, I., CONRATHS, F. J., MARQUARDT, O.
• Format: Journal Article
• Language: English
• Published: Berlin, Germany Blackwell Verlag GmbH 01.04.2002
• Subjects: Animals; Antibodies, Viral - blood; Base Sequence; Cattle; Disease Outbreaks - veterinary; DNA, Viral - blood; Egypt - epidemiology; Enzootic Bovine Leukosis - epidemiology; Enzootic Bovine Leukosis - pathology; Enzootic Bovine Leukosis - prevention & control; Enzyme-Linked Immunosorbent Assay - veterinary; Female; Leukemia Virus, Bovine - genetics; Leukemia Virus, Bovine - immunology; Male; Molecular Sequence Data; Polymerase Chain Reaction - veterinary; Polymorphism, Restriction Fragment Length; Quarantine - veterinary; Seroepidemiologic Studies; Egypt
• ISSN: 0931-1793; 1439-0450
• DOI: 10.1046/j.1439-0450.2002.00517.x

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 2 years old and of 72.8% in animals more than 2 years old. Diagnosis was confirmed by the detection of BLV proviral DNA using polymerase chain reaction with primers amplifying a fragment of the env gene. Out of 21 tested leucocyte fractions from individual animals, 15 were positive showing a BLV‐specific amplicon of 444 base pairs. Analysis of the amplicons for restriction fragment length polymorphisms and DNA sequencing results allowed the isolates to be typed. Since this was the first recorded case of enzootic bovine leukosis in Upper Egypt, strict quarantine measures were adopted and all serologically positive animals in the herd were culled.