No abstract

Summary An epornitic of avian pox occurred in a flock of 123 houbara bustards (Chlamydotis undulata macqueenii) received at the Sulman Falcon Hospital in the State of Bahrain in February 1993. Birds displayed conjunctivitis, excessive lacrimation and papilloma‐like growths forming amorphous clusters on the third eyelid and on the conjunctiva. Examination of eyelid samples under transmission electron microscopy revealed pox virus particles displaying the classical morphology of vaccinia‐avipox virions. Typical pox lesions were also detected 5 days post infection (p.i.) on chorioallantoic membrane (CAM). The virus titre on CAM was 107 focus‐forming units (FFU) /ml. In tissue culture, only a slight cytopathogenic effect (CPE) was detected 5 days p.i. The virus titre on cell cultures was 104.5 FFU/ml. The virus infection in cell culture appeared to be abortive and no CPE was seen after three passages in secondary chicken embryo fibroblasts. No neutralization of the cell‐grown virus was detected on serological studies using antisera directed against fowl, pigeon, canary and sparrowpox viruses. The discussion is framed around the different cultural properties of the houbara bustard pox virus isolate and its relationship to other known viral strains.

A precipitating antigen of bovine leukemia virus was isolated by isoelectric focusing and Sephadex gel filtration. In SDS-polyacrylamide gel electrophoresis it was found to be a homogeneous protein with a relative molecular weight of 69 000 daltons. Because of its relative molecular weight and staining characteristics it was designated as BLV gp69. A protein with the same molecular weight could also be demonstrated in BLV particles. In 34 out of 35 sera from cattle affected by enzootic bovine leukosis antibodies against gp69 were detected, whereas the sera from 197 animals, free of bovine leukosis, did not react in immunodiffusion test.