Abstract

The present work studied an outbreak of bovine ephemeral fever (BEF) at El-Salhia dairy farm during July and August 2015. The herd was consisting of 1600 previously vaccinated cows. Clinical examination of the herd revealed clinical signs lead to suspect infection with bovine ephemeral fever as fever; harried respiration; lameness and recumbency in 103 cows. Serum samples, buffy coats and blood plasma samples from the diseased cows were used for identification and characterization of recent isolates of BEFV. The 103 animals were found to have non-protective low titers of BEF antibodies (#x2264;2-8) as tested by serum neutralization test (SNT). Trials of virus isolation in baby mice brain and BHK21 cell culture from buffy coat and blood plasma samples revealed specific signs in inoculated mice (paralysis of the limbs, nervous symptoms, and death within 3-4 days post inoculation), and specific cytopathic effect in BHK-21 cell culture. Virus identification using virus neutralization tests (VNT) and direct fluorescent antibody technique (FAT) confirmed the presence of BEFV. Also, PCR, sequencing analysis and phylogenetic tree showed that the obtained isolate is closely related to Egypt-2005 strain. These findings indicated that BEF still causes a risk to the cattle industry in Egypt although there is an effective vaccine used against the disease. So much more studies should be conducted on the risk factors of the disease.