Isolation and phylogenetic analysis of camel contagious ecthyma virus in Morocco

Camel contagious ecthyma is a highly infectious viral skin disease that affects camels and causes economic losses. This study reports the isolation and the phylogenetic analysis of contagious ecthyma virus among camels in Morocco. The disease was detected in four among fifteen camels with severe papules on the lips and nares. Samples of skin crusts were collected and pooled for virus isolation and titration, PCR testing, and histopathological examination. PCR was used to amplify the B2L gene and the resulting product was sequenced and analyzed genetically. The study's findings indicate the presence of characteristic microscopic changes of poxvirus infection in the examined tissues and the virus was isolated on two cells (lambs testis and Vero) and showed distinct growth patterns. The virus grew rapidly on TA cells and delayed growth on Vero cells. The third passage showed cytopathic effects characterized by cell aggregation. Sequence analysis of the B2L gene revealed 100 % similarity to the camel contagious Ecthyma virus isolated from Ethiopia. The camel virus isolates can be classified into two genetic clades according to the B2L gene sequence: the Asian lineage, which includes isolates from Saudi Arabia, Bahrain, and India, and the African lineage, which includes isolates from the Sudan. In conclusion, this is the first instance of the camel contagious ecthyma virus being identified in North Africa in a herd of camels following exposure to stress. Moreover, the progression of the disease was closely monitored from onset to recovery in a setting without the bacterial complication often observed in the field. The virus exhibited opportunistic behavior, exploiting the stress response. Further studies are warranted to evaluate the pathogenicity of the virus in camels and to genetically characterize the circulating virus from different regions. This will be highly beneficial in the development of an appropriate vaccine.