Isolation of swine infertility and respiratory syndrome virus (isolate ATCC VR-2332) in North America and experimental reproduction of the disease in gnotobiotic pigs

• Published in: Journal of veterinary diagnostic investigation Vol. 4; no. 2; p. 117
• Main Authors: Collins, J.E. (University of Minnesota, St. Paul, MN), Benfield, D.A, Christianson, W.T, Harris, L, Hennings, J.C, Shaw, D.P, Goyal, S.M, McCullough, S, Morrison, R.B, Joo, H.S
• Format: Journal Article
• Language: English
• Published: United States 01.04.1992
• Subjects: AMERICA DEL NORTE; AMERIQUE DU NORD; ANIMAL DE LABORATOIRE; ANIMALES DE LABORATORIO; Animals; AXENIE; CERDAS; CERDO; Cytopathogenic Effect, Viral; Disease Outbreaks - veterinary; ENFERMEDADES RESPIRATORIAS; EXENCION DE PATOGENOS ESPECIFICOS; Female; Germ-Free Life; GNOTOBIOTIC ANIMALS; Infertility, Female - epidemiology; Infertility, Female - microbiology; Infertility, Female - pathology; Infertility, Female - veterinary; LABORATORY ANIMALS; LECHON; MALADIE RESPIRATOIRE; MINNESOTA; Minnesota - epidemiology; NORTH AMERICA; PIGLETS; PORCELET; PORCIN; PORCINE EPIDEMIC ABORTION AND RESPIRATORY SYNDROME; PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME; Pregnancy; Pregnancy Complications, Infectious - microbiology; Pregnancy Complications, Infectious - veterinary; REPRODUCCION; REPRODUCTION; RESPIRATORY DISEASES; Respiratory Tract Infections - epidemiology; Respiratory Tract Infections - microbiology; Respiratory Tract Infections - pathology; Respiratory Tract Infections - veterinary; SOWS; SPECIFIC PATHOGEN FREE STATE; SWINE; Swine Diseases - epidemiology; Swine Diseases - microbiology; Swine Diseases - pathology; Syndrome; TRUIE; VIRUS; Virus Diseases - epidemiology; Virus Diseases - microbiology; Virus Diseases - pathology; Virus Diseases - veterinary; Virus Physiological Phenomena; Virus Replication; VIRUSES; Viruses - isolation & purification; Viruses - pathogenicity; Minnesota
• ISSN: 1040-6387; 1943-4936
• DOI: 10.1177/104063879200400201

A recent epizootic of swine infertility and respiratory syndrome (SIRS) in a Minnesota swine herd was investigated. Examination of a sow, neonatal piglets, and stillborn fetuses obtained during the epizootic from the affected herd revealed interstitial pneumonitis, lymphomononuclear encephalitis, and lymphomononuclear myocarditis in the piglets and focal vasculitis in the brain of the sow. Fetuses did not have microscopic lesions. No cause for the infertility and respiratory syndrome was determined. Therefore, attempts were made to experimentally reproduce the disease. Eleven 3-day-old gnotobiotic piglets exposed intranasally to tissue homogenates of piglets from the epizootic became inappetent and febrile by 2-4 days postexposure and had interstitial pneumonitis and encephalitis similar to that seen in the field outbreak. After 2 blind passages in gnotobiotic piglets, tissue homogenates were cultured on continuous cell line CL2621, and a cytopathic virus (ATCC VR-2332), provisionally named SIRS virus, was isolated. Gnotobiotic piglets exposed intranasally to the SIRS virus developed clinical signs and microscopic lesions that were the same as those in piglets exposed to the tissue homogenates, and the virus was reisolated from their lungs. This is the first isolate of SIRS virus in the United States that fulfills Koch's postulates in producing the respiratory form of the disease in gnotobiotic piglets and the first report of isolation and propagation of the virus on a continuous cell line (CL2621). The virus is designated as American Type Culture Collection VR-2332.