Bovine ephemeral fever epidemics in Kingdom Saudi Arabia: clinical, epidemiological and molecular investigation.

Bovine ephemeral fever virus (BEFV) is an arthropod borne Rhabdovirus affects cattle and water buffalo causes acute febrile disease.The clinical picture and epidemiological pattern of BEF were described among cattle in epidemics of 2007, 2009 and 2011 in four geographical regions of Kingdom Saudi Arabia (Eastern, Jizan, Qasim, and Riyadh). Serum samples were tested using VNT. Virus isolation and molecular characterization were carried out for the first time in KSA.The main clinical symptoms were fever, stiffness, lameness, salivation and subcutaneous emphysema. The prevalence and the mortality rate of BEF have decreased from 70% and 4.6% in 2007 to 30% and 0.6% in 2011, respectively in the 4 studied areas. There was no region association with higher prevalence of BEF. The intracluster correlation (ICC) was estimated for the first time in KSA as 0.0034. BEFV had been isolated from 11 out of 20 samples (55%) and isolation was confirmed by VNT. The molecular detection of BEFV by RT-PCR and real- time RT-qPCR were found more sensitive for diagnosis of the disease than virus isolation; 80% and 90% for the former tests and 55% for the latter. Three isolates were sequenced, they showed 84.7% - 100% identities in between and shared 90.4%-96.5% sequence identity with a previously published sequence from Australia (KF679404). The generated sequences belonged to 3rd cluster of BEFV glycoprotein.BEF occurrence has cyclic nature and the efficacy of vaccines prepared from local strains has to be evaluated and considered in diseases control.