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Evaluation of porcine epidemic diarrhea virus transmission and the immune response in growing pigs.

Crawford K, Lager K, Miller L, Opriessnig T, Gerber P, Hesse R - Vet. Res. (2015)

Bottom Line: On Day 0 (D0), a growing pig was challenged with PEDV and 13 contacts were commingled.By D63, all N/C seroconverted.This demonstrates potential for an effective PEDV vaccine.

View Article: PubMed Central - PubMed

Affiliation: National Animal Disease Center, United States Department of Agriculture-Agricultural Research Services, Ames, IA, USA. Kimberly.crawford@ars.usda.gov.

ABSTRACT
Clinical disease associated with porcine epidemic diarrhea virus (PEDV) infection in naïve 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 (D0), a growing pig was challenged with PEDV and 13 contacts were commingled. On D7, 9 contact pigs (principal virus group (PG)), were selected, moved to a separate room and commingled with one sentinel pig (S1). 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. Pigs S1 and S2 were PEDV-positive within 24 hours of commingling. Antibodies were detected in all PG by D21 and by 7 days post-contact in S1 and S2. Pigs S3 and S4 were PCR and antibody negative following commingling. To evaluate protective immunity, 5 naïve pigs (N) and the PG were challenged (N/C, PG/C) with homologous virus on D49. All N/C pigs were PEDV PCR-positive by D52 with detection out to D62 in 3/5 N/C pigs. All PG/C pigs were PEDV PCR-negative post-challenge. By D63, all N/C seroconverted. Although PEDV RNA was demonstrated in pigs after primary infection until D42, infectious PEDV capable of horizontal transmission to naïve pigs 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.

No MeSH data available.


Related in: MedlinePlus

Experimental timeline of events. Experiment timeline from study initiation (Day 0) to termination (Day 78). On Day 0, the seeder pig was orally challenged with PEDV. On Days 1 and 2, 1 and 12 contact pigs, respectively were placed with the seeder pig. On Day 7, the Principle Group (PG) consisting of 9 contact pigs, and the Stationary Group (SG) consisting of 4 contact pigs and the seeder pig were selected. On Days 7, 14, 21, and 28, pigs S1, S2, S3, and S4, were commingled with the PG, respectively. On Days 10, 17, 24, and 31, the respective sentinel pig was removed and placed in a separate room. S1 was euthanized and necropsied on Day 30. All other study animals were euthanized and necropsied on Day 78. At Day 49 naïve pigs (N) and PG received PEDV challenge (PG/C: principal virus reservoir group post-challenge. N/C: naïve pigs post-challenge).
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Fig1: Experimental timeline of events. Experiment timeline from study initiation (Day 0) to termination (Day 78). On Day 0, the seeder pig was orally challenged with PEDV. On Days 1 and 2, 1 and 12 contact pigs, respectively were placed with the seeder pig. On Day 7, the Principle Group (PG) consisting of 9 contact pigs, and the Stationary Group (SG) consisting of 4 contact pigs and the seeder pig were selected. On Days 7, 14, 21, and 28, pigs S1, S2, S3, and S4, were commingled with the PG, respectively. On Days 10, 17, 24, and 31, the respective sentinel pig was removed and placed in a separate room. S1 was euthanized and necropsied on Day 30. All other study animals were euthanized and necropsied on Day 78. At Day 49 naïve pigs (N) and PG received PEDV challenge (PG/C: principal virus reservoir group post-challenge. N/C: naïve pigs post-challenge).

Mentions: Twenty-three, 4-week-old barrows from a PEDV-negative commercial source in Iowa, USA, were randomly assigned a livestock ear tag with a unique number placed in the left ear (Allflex USA, Dallas, TX, USA). A summary of the experimental design and the animal movement can be found in Figure 1. All animals were housed at the National Animal Disease Center, USDA-ARS campus in accordance with Institutional Animal Care and Use Committee protocols (protocol ACUP 2707) following the “Guide for the Care and Use of Agricultural Animals in Research and Teaching”. One ABSL2 isolation barn was dedicated to housing non-exposed animals (Barn 1) until moved to isolation Barn 2 for PEDV exposure. On Day (D) 0, a pig was selected from Barn 1 and placed into a room in Barn 2 at which time it was inoculated orally with PEDV and was designated as the “seeder” pig.Figure 1


Evaluation of porcine epidemic diarrhea virus transmission and the immune response in growing pigs.

Crawford K, Lager K, Miller L, Opriessnig T, Gerber P, Hesse R - Vet. Res. (2015)

Experimental timeline of events. Experiment timeline from study initiation (Day 0) to termination (Day 78). On Day 0, the seeder pig was orally challenged with PEDV. On Days 1 and 2, 1 and 12 contact pigs, respectively were placed with the seeder pig. On Day 7, the Principle Group (PG) consisting of 9 contact pigs, and the Stationary Group (SG) consisting of 4 contact pigs and the seeder pig were selected. On Days 7, 14, 21, and 28, pigs S1, S2, S3, and S4, were commingled with the PG, respectively. On Days 10, 17, 24, and 31, the respective sentinel pig was removed and placed in a separate room. S1 was euthanized and necropsied on Day 30. All other study animals were euthanized and necropsied on Day 78. At Day 49 naïve pigs (N) and PG received PEDV challenge (PG/C: principal virus reservoir group post-challenge. N/C: naïve pigs post-challenge).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4419466&req=5

Fig1: Experimental timeline of events. Experiment timeline from study initiation (Day 0) to termination (Day 78). On Day 0, the seeder pig was orally challenged with PEDV. On Days 1 and 2, 1 and 12 contact pigs, respectively were placed with the seeder pig. On Day 7, the Principle Group (PG) consisting of 9 contact pigs, and the Stationary Group (SG) consisting of 4 contact pigs and the seeder pig were selected. On Days 7, 14, 21, and 28, pigs S1, S2, S3, and S4, were commingled with the PG, respectively. On Days 10, 17, 24, and 31, the respective sentinel pig was removed and placed in a separate room. S1 was euthanized and necropsied on Day 30. All other study animals were euthanized and necropsied on Day 78. At Day 49 naïve pigs (N) and PG received PEDV challenge (PG/C: principal virus reservoir group post-challenge. N/C: naïve pigs post-challenge).
Mentions: Twenty-three, 4-week-old barrows from a PEDV-negative commercial source in Iowa, USA, were randomly assigned a livestock ear tag with a unique number placed in the left ear (Allflex USA, Dallas, TX, USA). A summary of the experimental design and the animal movement can be found in Figure 1. All animals were housed at the National Animal Disease Center, USDA-ARS campus in accordance with Institutional Animal Care and Use Committee protocols (protocol ACUP 2707) following the “Guide for the Care and Use of Agricultural Animals in Research and Teaching”. One ABSL2 isolation barn was dedicated to housing non-exposed animals (Barn 1) until moved to isolation Barn 2 for PEDV exposure. On Day (D) 0, a pig was selected from Barn 1 and placed into a room in Barn 2 at which time it was inoculated orally with PEDV and was designated as the “seeder” pig.Figure 1

Bottom Line: On Day 0 (D0), a growing pig was challenged with PEDV and 13 contacts were commingled.By D63, all N/C seroconverted.This demonstrates potential for an effective PEDV vaccine.

View Article: PubMed Central - PubMed

Affiliation: National Animal Disease Center, United States Department of Agriculture-Agricultural Research Services, Ames, IA, USA. Kimberly.crawford@ars.usda.gov.

ABSTRACT
Clinical disease associated with porcine epidemic diarrhea virus (PEDV) infection in naïve 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 (D0), a growing pig was challenged with PEDV and 13 contacts were commingled. On D7, 9 contact pigs (principal virus group (PG)), were selected, moved to a separate room and commingled with one sentinel pig (S1). 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. Pigs S1 and S2 were PEDV-positive within 24 hours of commingling. Antibodies were detected in all PG by D21 and by 7 days post-contact in S1 and S2. Pigs S3 and S4 were PCR and antibody negative following commingling. To evaluate protective immunity, 5 naïve pigs (N) and the PG were challenged (N/C, PG/C) with homologous virus on D49. All N/C pigs were PEDV PCR-positive by D52 with detection out to D62 in 3/5 N/C pigs. All PG/C pigs were PEDV PCR-negative post-challenge. By D63, all N/C seroconverted. Although PEDV RNA was demonstrated in pigs after primary infection until D42, infectious PEDV capable of horizontal transmission to naïve pigs 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.

No MeSH data available.


Related in: MedlinePlus