Clinical disease associated with porcine epidemic diarrhea virus (PEDV) infection in naive pigs is well chronicled; however, information on endemic PEDV infection is limited. To characterize chronic PEDV infection, the duration of infectious virus shedding and development of protective immunity was determined. On Day 0 (DO), a growing pig was challenged with PEDV and 13 contacts were comingled. On D7, 9 contact pigs (principal virus group (PG)), were selected, moved to a separate room and comingled with one sentinel pig (SI). This process was repeated weekly with S2, S3 and S4. The PG was PEDV-positive by PCR from D3-11, with some pigs intermittently positive to D42. SI and S2 were PEDV-positive within 24 hours of comingling. Antibodies were detected in all PG by D21 and by 7 days post-contact in S1 and S2. S3 and S4 were PCR and antibody negative. To evaluate protective immunity, 5 naive pigs (N) and the PG were challenged (N/C, PG/C) with homologous virus on D49. All N/C pigs were PEDV-positive by D52 with detection to D62 in 3/5 N/C pigs. All PG/C pigs were PEDV-negative post-challenge. By D63, all N/C se-roconverted. Although PEDV PvNA was demonstrated in pigs after primary infection until D42, infectious PEDV capable of transmission to naivepigs was only shed 14-16 days after infection to age-matched pigs. Homologous re-challenge 49 days post initial PEDV exposure did not result in re-infection of: the pigs. This demonstrates potential for an effective PEDV vaccine.
展开▼
