Clinical forms and molecular identification of BVDV biotype 2 outbreaks in some Egyptian farms with risk assessment

This study aimed to investigate the occurrence of bovine viral diarrhea virus (BVDV) infection in a total 321 cattle heifers in 4 different farms located in Egypt with risk factors assessment. Case history, clinical investigation, and blood samples were collected for molecular identification by a nested multiplex PCR using specific primers targeting the NS5B gene. Phylogenetic analysis was performed for genotyping. The obtained results cleared the presence of multiple clinical signs, but the most prominent ones were profuse, watery diarrhea with an average of 56% and mucosal lesions in the form of erosions with different degrees of severeness and healing tissues with an average of 24.6 %. Meanwhile, the most significant outcome was the presence of abortion in 17.7 % of the infected cases. Molecular detection and genotyping of the obtained strains showed the presence of genetically related 3 strains of BVDV type 2 only with no genetic variance. The morbidity rate of the BVDV infection in the investigated herds was found to be (44/321) 13.7 %. Meanwhile, the mortality rate was 6.8% (22/321). There is a positive relation between the morbidity rate and the herd size and dairy herds compared to the medium-sized and beef herds, respectively. It could be concluded that this study provides valuable insights into the prevalence and genetic diversity of BVDV in the examined cattle population. These findings contribute to the understanding and control of BVDV infection in Egypt and highlight the importance of implementing effective management strategies and vaccination programs to prevent its spread.