Do all PRRSV variants have the same infectivity?
Three PRRSV variants differed in experimental infectivity, with L1C.5 requiring fewer infectious units to infect half of the pigs.
Three PRRSV variants differed in experimental infectivity, with L1C.5 requiring fewer infectious units to infect half of the pigs.
Problem: PRRSV genetic variants are often compared by sequence, but their biological infectious doses may differ.
Methods: For each of three variants, groups of six pigs received 2 mL intranasally at five concentrations ranging from 10⁰ to 10⁴ TCID50/mL and were followed for up to 28 days.
1. Estimated ID50 values at 4 days were 10²·⁶ TCID50/mL for L9A, 10²·³ for L1A, and 10¹·³ for L1C.5.
2. No apparent differences in nasal or rectal shedding patterns were observed among the tested variants.
3. L1C.5 required fewer infectious units to infect half of the pigs and produced more extensive microscopic lesions, demonstrating differences in infectivity and pathogenicity among PRRSV variants in this experimental model.
Original publication
Melini CM et al. Evaluation of the infectivity of three PRRSV variants. Veterinary Research. 2025;56:158.