First Molecular Characterization of Small Ruminant Lentiviruses Detected in Romania

Simple Summary Small ruminant lentiviruses (SRLVs) are a group of highly diverse viruses responsible for global infections in goats and sheep. The purpose of this study was to genetically characterize SRLVs circulating in Romania. A total of 122 samples from pulmonary and lung lymph nodes of slaughtered sheep were examined. The obtained gag-pol and gag sequences from Romanian SRLV strains were compared with available GenBank strains, and the results showed that the Romanian sequences were associated with strains A2 and A3 based on gag-pol sequences and with subtypes A3 and A17 based on gag sequences. In addition, the Romanian sequences showed some specific mutations in epitope 3, which may reflect their evolution. This study describes for the first time SRLV sequences detected in Romanian sheep, providing basic information on the subtypes circulating in Romania.Abstract Small ruminant lentiviruses (SRLVs) are a group of retroviruses that cause multisystem chronic diseases in goats and sheep and lead to production losses in these animals, negatively affecting animal health and welfare. Although molecular characterization of SRLV field isolates has been performed in many countries, there is currently no information on SRLV genotypes circulating in sheep and goats in Romania. Therefore, the main objective of this study was to conduct a molecular and phylogenetic analysis of SRLVs from Romania and determine the degree of genetic relatedness of the obtained sequences to other known SRLV reference strains. A total of 81 sheep lung tissue samples and 41 sheep lung lymph node samples were tested using nested real-time PCR, and samples positive for real-time PCR were used to amplify an 800 bp gag-pol fragment and an overlapping 625 bp fragment of the gag gene. Pairwise DNA distance and phylogenetic analysis showed that the Romanian SRLV strains were closely related to the A2 and A3 strains based on gag-pol sequences and to the A3 and A17 subtypes based on gag sequences. No recombination events were found. Our results revealed that the Romanian sequences have similar epitope patterns to other existing subtypes, although E/K and R/K mutations in epitope 3 were found only in the Romanian sequences, which may have potential value in serological diagnosis. This study is the first report on the genetic characterization of SRLV strains circulating in Romania and provides new information on SRLV heterogeneity. Further detailed studies should be conducted to better understand the divergence of SRLV Romanian strains.