ERVW-1 and infection: Anti-SU antibody ELISA responses were similar between presumptively regressive infections and pooled vaccinated/unvaccinated abortive infections (n = 50; 2.2/2.3 against FeLV-A/FeLV-B) (p = 0.10 for FeLV-A, p = 0.62 for FeLV-B; Mann–Whitney U-tests; Figure 3).