First Molecular Characterisation of the Lumpy Skin Disease Virus From the North African Region, Algeria and Tunisia

Lumpy skin disease (LSD) is a vector-transmitted viral disease that affects cattle and water buffaloes. The LSD virus (LSDV) is a double-stranded DNA virus and is a member of the Poxviridae family. The first documented cases of LSD were reported in Zambia in 1929, from which it spread to other countries in sub-Saharan Africa, as well as to countries in Europe and Asia. The present study documents the first occurrence of LSD in the North African region. Different samples were collected from infected cattle in Algeria and Tunisia, and morbidity data were recorded. To confirm the occurrence of LSDV, polymerase chain reaction (PCR) and sequencing were performed on the basis of the p32 gene. The symptoms associated with LSD infection in both countries include lymph node enlargement, the presence of lumps in several parts of the body and the occurrence of high fever. The PCR detected the p32 gene of the LSDV in 77.9% (60/77) of the collected samples, and cattle skin, nasal and buccal swabs were identified as the most virulent materials. Phylogenetic analysis employing the p32 gene sequence from two amplicons revealed 100% sequence identity to GenBank-published LSDV sequences and grouped with amplicons predominantly isolated from Egypt (MZ665552.1), Zimbabwe (KX033500.1), various Asian countries and Russia. It is important to note that the phylogenetic analysis based on the p32 gene sequence is limited and poorly discriminative in comparison to whole genome sequencing, which is better at identifying the cluster to which a circulating virus belongs. The implementation of the Neethling strain vaccine in Algeria and Tunisia, in conjunction with the unfavourable climatic conditions conducive to vector multiplication, resulted in a substantial decline in clinical cases.