Bovine viral diarrhea virus isolated from fetal calf serum enhances pathogenicity of attenuated transmissible gastroenteritis virus in neonatal pigs.
A bovine viral diarrhea virus (BVDV-C) was isolated from swine tissue culture cells used to attenuate the transmissible gastroenteritis virus (TGEV) after 68 passes. Piglets given a pure culture of BVDV-C developed clinical signs similar to those of a mild TGEV infection and recovered by 10 days postexposure. Villous blunting and fusion was observed in the small intestine, and a lymphocyte depletion was observed in Peyer's patches in the ileum. Piglets given a combination of BVDV-C and attenuated TGEV developed clinical signs similar to those of a virulent TGEV infection and were euthanized. The combined infection induced a generalized lymphocyte depletion throughout the lymphatic system and villous atrophy in the intestinal tract. Piglets exposed to a another type I strain of BVDV (NY-1) either alone or in combination with the attenuated TGEV had mild clinical signs similar to those of a TGEV infection. Moderate villous atrophy in the ileum and a lymphocyte depletion in the mesenteric lymph node were observed in these piglets postmortem. The data indicate a potential problem for diagnostic laboratories in relation to a diagnosis of virulent TGEV infections and in the field for young piglets exposed to a BVDV-contaminated TGEV vaccine.
Woods
R D
RD
Virology Swine Research Unit, National Animal Disease Center, USDA, Agricultural Research Service, Ames, IA 50010, USA.
Kunkle
R A
RA
Ridpath
J E
JE
Bolin
S R
SR
D000818:Animals; D001912:Bovine Virus Diarrhea-Mucosal Disease; D002417:Cattle; D018929:Cell Culture Techniques; D003937:Diagnosis, Differential; D001908:Diarrhea Viruses, Bovine Viral / Q000472:pathogenicity*; D004064:Digestive System / Q000473:pathology; D005761:Gastroenteritis, Transmissible, of Swine; D015203:Reproducibility of Results; D013552:Swine; D005760:Transmissible gastroenteritis virus / Q000472:pathogenicity*; D014613:Vaccines, Attenuated / Q000276:immunology* / Q000494:pharmacology; D014765:Viral Vaccines / Q000276:immunology* / Q000494:pharmacology; D014774:Virulence
D014613:Vaccines, Attenuated; D014765:Viral Vaccines