Detection and Phylogenetic Analysis of the Tegument Protein Gene of Malignant Catarrhal Fever Virus from Clinical Cases of Cattle and Sheep in the Central Balkan Region

This study aimed to describe the clinical course of SA-MCF and the duration of viremia in surviving cattle and to perform the phylogenetic analysis of the tegument protein gene of OvHV-2 in cattle in the Central Balkan. A farm housing two heifers and 7 sheep with a confirmed SA-MCF case were selected for the investigation. For the estimation of the length of viremia and the virus shedding, the animals were sampled repeatedly, weekly for two months. For the phylogenetic analysis, a retrospective study was performed on 21 samples from cattle, and 7 samples from sheep, from the Central Balkan. In the blood samples of the survived heifer, the OvHV-2 genome was detected until week 7, in corneal swabs, the OvHV-2 genome was detected until week 6, and in nasal swabs until week two of the study. A retrospective study revealed that out of 21 tested cattle, OvHV–2 was detected in 15 (71.4%), and out of 7 tested sheep, three (42.9%) were positive. The sequenced samples show the highest percentage of similarity with the strains from Brasil KJ658293.1 (100%) and Germany HM216475.1 (100%).. Since there is a variety of different clinical signs similar to other notifiable diseases such as BVD, IBR, and FMD, there is a clear benefit in including SA-MCF in the differential diagnosis in cattle. As mixed farming in the Central Balkan is practiced, implementing SA-MCF monitoring in passive surveillance would allow a better understanding of the disease, ascertaining its prevalence and could provide new information regarding SA-MCF epidemiology