Pathogenicity and phylogenetic analysis of ovine contagious ecthyma virus isolated during a sheeppox outbreak in Morocco

Contagious ecthyma (CE), also known as ORF is a highly contagious zoonotic viral skin disease that affects humans, sheep, goats and other domesticated and wild animals. As reported here-in, the objective of this study was to investigate a suspected outbreak of both sheeppox and ORF diseases in a sheep herd during the winter of 2020 in Northwest Morocco. The affected sheep showed nodules and proliferative scabby skin lesions around the mouth and hairless area of the body. Samples of skin crust were collected for virus identification and isolation. A virus was isolated in Vero cells, lamb testis and heart cells and the cytopathic effect was characterized by cells aggregation, ballooning, and detachment. Initially, the suspensions of skin crust were positive for sheeppox virus (SPPV) by PCR. Subsequent testing of the isolated virus from skin crust of affected animals indicated that the virus was SPPV-negative and ORFV-positive by PCR. Furthermore, nucleotide sequences of the B2L aligned with reference ORFV isolates for genetic analysis. Phylogenetic analyses results confirmed that the isolated virus was ORFV and that the virus was closely related to ORFV strains isolated in Sudan and Malaysia. In conclusion, this study is the first reported detection of ORFV in Morocco, and therefore, poses as an imminent threat to the health of humans, domestic and wild animals.