Role of Rhipicephalus Annulatus Tick in Transmission of Lumpy Skin Disease Virus in Naturally Infected Cattle in Egypt

| Lumpy skin disease (LSD) is an infectious viral disease of cattle that results in serious economic and international trade consequences. Recently, hard ticks have been incriminated in lumpy skin disease virus (LSDV) transmission. The present study attempted to investigate the role of Rhipicephalus annulatus ticks, collected from naturally infected animals, in the transmission of LSDV. A total of 300 naturally infected cattle exhibiting the acute signs of LSD were clinically examined. Skin nodules and R. annulatus stages were collected from the diseased cattle. Samples were examined by PCR for the P32 gene and positive samples were confirmed by direct gene sequencing. . Female engorged ticks were incubated for eggs deposition. LSDV infections in eggs and larvae that hatched from these eggs were screened by virus isolation on the chorioallontoic membrane (CAM) of embryonated chicken egg (ECE) and confirmed by PCR. Characteristic pock lesions were observed on the inoculated CAM. Positive PCR results were obtained from skin lesions, eggs, larvae and pock lesions of the CAM. Sequence analysis of the terminal 174bp of the P32 gene of LSDV sequences revealed a high degree of similarity to LSDV sequences available in Genbank database. The obtained results are highly suggestive for the possibility of the vertical transmission of LSDV in Rhipicephalus annulatus female ticks.