title: Herd-level risk factors for the seropositivity to Mycoplasma hyopneumoniae and the occurrence of enzootic pneumonia among fattening pigs in areas of endemic infection and high pig density.
abstract: The aim of the present study was to identify potential risk factors for the occurrence of enzootic pneumonia (EP) in herds situated in a region of high pig density, where a majority of herds is endemically infected with Mycoplasma hyopneumoniae. Between 2006 and 2010, overall 100 herds were enrolled in a case-control study. Data were collected through personal interview with the farmers, clinical examination of pigs and their environments, and serological testing for M. hyopneumoniae, swine influenza virus and porcine reproductive and respiratory syndrome virus. There were 40 case herds (coughing index high, seroprevalence high) with a mean coughing index of 4.3 and a seroprevalence of 86.6%. There were two control groups. Control group I consisted of 25 herds (coughing index low, seroprevalence low) with mean values of 0.7 and 11.2%, and 35 herds were allocated to control group II (coughing index low, seroprevalence high) where the mean coughing index was 0.9 and seroprevalence 86.3%. Case herds and control II herds had an increased age of piglets at weaning compared to control I herds. Any contact between fattening pigs of different age during restocking of compartments increased the risk for the occurrence of EP in a herd. Finally, farms that use living animals for the exposure to gilts during the acclimatization and farms that had increased number of weaned piglets per sow and year were less likely to test positive for M. hyopneumoniae and less likely to develop clinical symptoms of EP in fattening pigs.
authors.affiliation: Field Station for Epidemiology, University of Veterinary Medicine Hannover, Foundation, Bakum, Germany; Veterinary Epidemiology and Public Health Group, The Royal Veterinary College, Hatfield, Hertfordshire, UK.
authors.forename: H
authors.initials: H
authors.lastname: Nathues
authors.forename: Y M
authors.initials: YM
authors.lastname: Chang
authors.forename: B
authors.initials: B
authors.lastname: Wieland
authors.forename: G
authors.initials: G
authors.lastname: Rechter
authors.forename: J
authors.initials: J
authors.lastname: Spergser
authors.forename: R
authors.initials: R
authors.lastname: Rosengarten
authors.forename: L
authors.initials: L
authors.lastname: Kreienbrock
authors.forename: E
authors.initials: E
authors.lastname: Grosse Beilage
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D016022:Case-Control Studies; D019353:Endemic Diseases / Q000662:veterinary*; D005260:Female; D008297:Male; D045705:Mycoplasma hyopneumoniae / Q000276:immunology; D045729:Pneumonia of Swine, Mycoplasmal / Q000097:blood / Q000453:epidemiology* / Q000276:immunology; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D012698:Serologic Tests; D011795:Surveys and Questionnaires; D013552:Swine
chemical_list: D000907:Antibodies, Bacterial