Lumpy skin disease in cattle in Sharkia, Egypt: epidemiological and genetic characterization of the virus

Lumpy skin disease virus (LSDV) continues to threaten the cattle industry in Egypt. This survey investigated the epidemiological risk factors and the genetic characterization of circulating strains by partial sequencing of the P32 gene on cattle farms in the Sharkia Governorate, Egypt. Out of 600 cattle examined, morbidity, mortality, and case fatality were 31.2%, 1.8%, and 5.9%, respectively. Risk of LSD was higher among unvaccinated cattle kept outdoors compared to vaccinated cattle kept indoors, and the prevalence rates were statistically significantly different (P < 0.05). Regarding seasonal distribution, the highest number of cases was in June and July, and the lowest was in November. The P32 gene sequences showed that two LSDV isolates were 100% identical and 99.26% identical with 2017 Russian LSDV. Phylogenetic analysis revealed that two local isolates in this study were grouped together with other LSDVs from Russia (Saratov), Kenya, Greece, and Israel. The sequences in the study and other Egyptian sequences were grouped into two clusters with low genetic divergence, indicating that different strains are spreading in Egypt and that LSDV is more genetically related to sheep poxviruses than goat poxviruses. Our study confirms the necessity of evaluating the vaccination strategy adopted in Egypt, and sequence analysis based on the P32 gene is appropriate for genetic epidemiological studies of the local LSDVs.