Serological response to Actinobacillus pleuropneumoniae serovar 7 infection in a commercial pig herd.
Serological responses to Actinobacillus pleuropneumoniae serovar 7 infection were monitored by enzyme-linked immunosorbent assay in a cohort of 66 pigs between weaning and market. Antibody concentrations were high (63/65 seropositive) at 4 weeks of age but declined to low levels from 8 to 12 weeks. Mean antibody concentrations rose significantly (p less than 0.001) between 12 and 23 weeks. Between 8 and 23 weeks of age, 33 (51.5%) of 64 surviving pigs seroconverted to A pleuropneumoniae serovar 7. Peak antibody concentrations in the seroconverting pigs usually (28/33) occurred at 23 weeks. Seroconversion to A pleuropneumoniae during the grower/finisher phase was not significantly associated (p greater than 0.05) with passive antibody concentrations at 4 weeks of age, lack of vaccination against Mycoplasma hyopneumoniae, or weaning weight. Pleuropneumonic lesions were evident at slaughter in 4 (6.3%) of 64 pigs. A pleuropneumoniae serovar 7 was isolated from 2 of 4 lungs with pleuropneumonia and from another lung with lesions considered typical of enzootic pneumonia.
Gardner
I A
IA
Department of Epidemiology and Preventive Medicine, School of Veterinary Medicine, University of California, Davis 95616.
Bossé
J T
JT
Sheldrake
R F
RF
Rosendal
S
S
Johnson
R P
RP
D000189:Actinobacillus Infections / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D016977:Actinobacillus pleuropneumoniae / Q000276:immunology*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001428:Bacterial Vaccines; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay; D009174:Mycoplasma / Q000276:immunology; D011001:Pleuropneumonia / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D013552:Swine; D013553:Swine Diseases / Q000276:immunology* / Q000473:pathology; D014611:Vaccination / Q000662:veterinary
D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines