Small ruminant lentivirus genotype E is widespread in Sarda goat

Area of Science:

• Veterinary Virology
• Infectious Diseases
• Lentivirus Research

Background:

• Small Ruminant Lentivirus (SRLV) genotype E, a caprine lentivirus, was recently identified in Italy.
• SRLV genotype E is characterized as low pathogenic in the Roccaverano goat breed.
• A genotype-specific diagnostic test enables serosurveys in diverse goat populations.

Purpose of the Study:

• To conduct a serological survey for SRLV genotype E in Sardinian sheep and goat populations.
• To genetically characterize a Sardinian SRLV genotype E isolate.
• To compare the Sardinian isolate with the prototype Roccaverano strain.

Main Methods:

• Serological survey using individual sera and bulk milk samples.
• Comparative assay with genotype-specific recombinant antigens.
• Full-length proviral sequencing and genetic analysis of isolates.

Main Results:

• SRLV genotype E was detected in over 50% of Sardinian goat herds, but not in sheep flocks.
• The Sardinian isolate showed significant genetic divergence (≤84% similarity) from the Roccaverano strain, indicating subtypes within genotype E.
• In vitro analysis revealed distinct properties of the Sardinian strain, including differences in synovial membrane infection and syncytia production, with env gene sequences resembling arthritic strains.

Conclusions:

• SRLV genotype E is specifically associated with goats and widely diffused in Sardinia.
• Genetic and in vitro differences support the designation of at least two subtypes within SRLV genotype E.
• The findings suggest a broader epidemiological spread of SRLV genotype E than previously recognized.