STAPHYLOCOCCUS AUREUS PROTEIN A FOR IMPROVING THE PERFORMANCE OF TRANSMISSION ELECTRON MICROSCOPY FOR DIAGNOSIS OF BOVINE EPHEMERAL FEVER
Iman M. Bastawecy; omayma M.El-Desawy; A.A.Saad and Hala A. Salem
Dept. of virology, Animal Health Research Institute, Dokki, Cairo
Accurate diagnosis of bovine ephemeral fever (BEF) in naturally infected cattle was achieved by isolation of the causative virus in suckling mice, followed by isolation in vero cell line. Identification of the isolates was attempted using Staphylococcus aureus protein A coagglutination test (SPA-COAT), virus neutralization test (VNT), negative staining electron microscopy, coagglutination clumping ultrasturctural analysis (SPA COA-TEM) and histopathological examination of the suckling mice brains used for isolation. Our results denote the usefulness of suckling mice for intracerebral inoculation to isolate BEF virus, followed by passaging them in vero cell cultures to identify the virus causing cytopathic effect (CPE) with VNT which identify it as BEF virus. SPA-COAT was used as rapid, accurate, specific, sensitive and economic. When EM is available, negative staining TEM can be applied for identification as rapid, specific and gold standard technique. BEF virus antibodies prepared in rabbits and mixed with Staphylococcus aureus protein A could be used to improve performance of TEM and to certify accuracy of SPA-COAT. Further studies are recommended to know why the antigenecity and pathogenecity of BEF virus was attenuated during passaging in suckling mice or tissue culture.