Experimental infections of the porcine foetus with Bungowannah virus, a novel pestivirus.
In 2003 an outbreak of sudden deaths occurred in 2-3-week-old pigs on a piggery in New South Wales, Australia. There was a marked increase in the birth of stillborn pigs and preweaning losses associated with a multifocal non-suppurative myocarditis with myonecrosis. The aim of this study was to amplify any infectious agents present in field material to aid the detection and identification of the causative agent of the porcine myocarditis syndrome (PMC). Foetuses were directly inoculated in utero with tissue extracts from field cases of PMC at 56-60, 70-84 or 85-94 days of gestation and euthanased 7-28 days later. The IgG concentration in foetal sera/body fluids was measured, hearts were examined by light microscopy and selected hearts were examined by electron microscopy. An infectious agent was detected in tissues from cases of PMC and its identification as the novel pestivirus Bungowannah virus has recently been reported (Kirkland et al., 2007). Sow sera, foetal tissues and foetal sera/body fluids were tested for Bungowannah virus RNA by qRT-PCR and antibody by peroxidase-linked assay. Bungowannah virus was detected in numerous organs of the porcine foetus. Following direct foetal exposure it is probable that this virus spreads by direct intra-uterine transmission to adjacent foetuses and by trans-uterine transmission to the dam. Data were obtained for both the replication of the virus in the porcine foetus and the humoral immune response in the foetus and sow.
Finlaison
Deborah S
DS
Virology Laboratory, Elizabeth Macarthur Agricultural Institute, Industry and Investment NSW, Private Bag 4008, Narellan, NSW 2567, Australia. deborah.finlaison@industry.nsw.gov.au
Cook
Roger W
RW
Srivastava
Mukesh
M
Frost
Melinda J
MJ
King
Katherine R
KR
Kirkland
Peter D
PD
D000818:Animals; D004196:Disease Outbreaks / Q000662:veterinary; D005065:Euthanasia; D005260:Female; D005315:Fetal Diseases / Q000276:immunology / Q000662:veterinary / Q000821:virology; D056724:Immunity, Humoral; D007074:Immunoglobulin G / Q000097:blood; D009205:Myocarditis / Q000276:immunology / Q000662:veterinary / Q000821:virology; D009517:New South Wales / Q000453:epidemiology; D010576:Pestivirus / Q000235:genetics* / Q000472:pathogenicity; D018182:Pestivirus Infections / Q000453:epidemiology / Q000276:immunology / Q000635:transmission / Q000662:veterinary*; D011247:Pregnancy; D012367:RNA, Viral / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000276:immunology / Q000635:transmission / Q000821:virology*
D007074:Immunoglobulin G; D012367:RNA, Viral