CPB 697 RESEARCH SEMINAR
Dr. Ingeborg Langohr
Graduate Student in Interdisciplinary Comparative Medicine
Department of Comparative Pathobiology
“Experimental Infection Of
Cesarean-Derived, Colostrum-Deprived Pigs
With Bovine Viral Diarrhea Virus And
Porcine Circovirus Type 2”
Thursday, March 6, 2008
VPTH
112
3:30
pm
ABSTRACT:
Porcine circovirus-associated disease (PCVAD) is considered a multifactorial disease since a variety of co-factors, including infectious agents, seem to be necessary for full expression of clinical disease. To investigate if ruminant pestiviruses are an additional co-factor in PCVAD, cesarean-derived, colostrum-deprived pigs were inoculated intramuscularly and intranasally with porcine circovirus type 2-1 (PCV2-1) and a cytopathic strain of bovine viral diarrhea virus type 1 (cpBVDV-NADL) either alone or in combination. Most of the animals remained healthy throughout the study. The majority of the pigs inoculated with PCV2-1 developed gross and microscopic lesions of classic PCVAD. Clinical signs were seen in a single animal inoculated with PCV2-1 only. This pig had growth retardation over 12 days followed by acute respiratory distress leading to death 30 days post infection. Gross and microscopic lesions in this animal resembled the severe form of PCVAD recently observed in the field. The number of viral genomic copies, serologic response and lesion severity did not differ significantly between pigs inoculated with PCV2-1 only and with both PCV2-1 and cpBVDV-NADL. Thus, there was no evidence that infection with the NADL strain of BVDV enhanced PCV2-1 replication and lesion formation. Experimental reproduction of clinical signs and lesions typical of the more severe form of PCVAD in one of the pigs inoculated only with PCV2-1 supports the theory that circulation of this new viral genotype in the North American pig population may account for the change in the presentation of the disease.