Isolation of Swine Infertility and Respiratory Syndrome Virus (Isolate ATCC VR-2332) in North America and Experimental Reproduction of the Disease in Gnotobiotic Pigs

Abstract

Abstract.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.

Indian porcine reproductive and respiratory syndrome virus bears discontinuous deletion of 30 amino acids in nonstructural protein 2

“…Now the disease occurs in most pig-producing countries and causes great economic loss to swine industry worldwide except for few countries including Switzerland, New Zealand and Australia [7,21]. The causative agent, PRRSV, is an enveloped, single-stranded, positive-sense RNA virus with an approximate diameter of 50-65 nm and belongs to the family Arteriviridae in the order of Nidovirales [8,31]. There are two distinct genotypes of PRRSV: genotype 1 (European) and genotype 2 (North American) which, share only about 60 % identity on the nucleotide level, while individual PRRSV isolates within genotypes varies approximately 20 % in nucleotide sequence [13,19].…”

Involvement of proteases in porcine reproductive and respiratory syndrome virus uncoating upon internalization in primary macrophages

“…* Corresponding author: peter.delputte@UGent.be problems in pigs of all ages, in combination with other pathogens [7,8,21,28]. In vivo, PRRSV has a predilection for differentiated macrophages [18,44].…”

Comparison of Porcine Reproductive and Respiratory Syndrome Virus Growth in Media Supplemented with Fetal Bovine Serum or a Serum Replacement

“…9 The first US PRRSV isolate was isolated on a continuous cell line, ATCC CL2621. 3 In addition to PAM cultures 9 and the CL2621 cell line, 3 the MARC 145 7 and ATCC CRL11171 8 cell lines also support PRRSV replication. Both US and European PRRSV isolates replicate well in PAM cultures, but the difficulties and expense in obtaining these cells limit their use.…”