Subject(s)
Antibody Formation , Immunity, Cellular , Porcine Reproductive and Respiratory Syndrome/immunology , Swine Diseases/immunology , Swine/immunology , Animals , Orthomyxoviridae Infections/immunology , Orthomyxoviridae Infections/virology , Porcine Reproductive and Respiratory Syndrome/virology , Recurrence , Reference Values , Swine Diseases/virologySubject(s)
Porcine Reproductive and Respiratory Syndrome/virology , Porcine respiratory and reproductive syndrome virus/physiology , Animals , Flow Cytometry/veterinary , Genetic Variation/immunology , Immunophenotyping/veterinary , Lung/virology , Lymph Nodes/virology , Open Reading Frames , Palatine Tonsil/virology , Porcine respiratory and reproductive syndrome virus/genetics , Porcine respiratory and reproductive syndrome virus/immunology , Porcine respiratory and reproductive syndrome virus/pathogenicity , RNA, Viral/chemistry , RNA, Viral/genetics , Reverse Transcriptase Polymerase Chain Reaction/veterinary , Swine , Viremia/veterinary , VirulenceABSTRACT
Three very severe episodes of Escherichia coli infection in hens from the same farm, at the beginning of laying, are reported. They were characterized by no clinical signs, but sudden mortality, from 5 to 10%, with severe lesions of septicaemia and fibrinous polyserositis. A Gram-negative bacterium was consistently isolated in pure culture from tissues. Isolates were typed biochemically as E. coli, but they were lactose negative and non-motile. The serotyping tests typed the isolates as somatic group O111. The isolates were sensitive to enrofloxacin, amoxycil and colimycin, and partially sensitive to flumequine, all of which were used for therapy. The disease was reproduced experimentally in both specific pathogen free chickens and commercial layers by intramuscular inoculation of the E. coli, but only in some layers when inoculated by the oro-nasal route. The stress of the onset of lay seemed to be the most probable precipitating cause of the disease.
