title: Individual risk factors for Mycoplasma hyopneumoniae infections in suckling pigs at the age of weaning.
abstract: BACKGROUND
  In recent years, the occurrence and the relevance of Mycoplasma hyopneumoniae infections in suckling pigs has been examined in several studies. Whereas most of these studies were focused on sole prevalence estimation within different age groups, follow-up of infected piglets or assessment of pathological findings, none of the studies included a detailed analysis of individual and environmental risk factors. Therefore, the aim of the present study was to investigate the frequency of M. hyopneumoniae infections in suckling pigs of endemically infected herds and to identify individual risk factors potentially influencing the infection status of suckling pigs at the age of weaning.
  
  
  RESULTS
  The animal level prevalence of M. hyopneumoniae infections in suckling pigs examined in three conventional pig breeding herds was 3.6% (41/1127) at the time of weaning. A prevalence of 1.2% was found in the same pigs at the end of their nursery period. In a multivariable Poisson regression model it was found that incidence rate ratios (IRR) for suckling pigs are significantly lower than 1 when teeth grinding was conducted (IRR: 0.10). Moreover, high temperatures in the piglet nest during the first two weeks of life (occasionally >40°C) were associated with a decrease of the probability of an infection (IRR: 0.23-0.40). Contrary, the application of PCV2 vaccines to piglets was associated with an increased infection risk (IRR: 9.72).
  
  
  CONCLUSIONS
  Since single infected piglets are supposed to act as initiators for the transmission of this pathogen in nursery and fattening pigs, the elimination of the risk factors described in this study should help to reduce the incidence rate of M. hyopneumoniae infections and thereby might contribute to a reduced probability of high prevalences in older pigs.
authors.affiliation: Field Station for Epidemiology, University of Veterinary Medicine Hannover, Foundation, Buescheler Street 9, Bakum, D-49456, Germany. heiko.nathues@tiho-hannover.de
authors.forename: Heiko
authors.initials: H
authors.lastname: Nathues
authors.forename: Stefanie
authors.initials: S
authors.lastname: Doehring
authors.forename: Henrike
authors.initials: H
authors.lastname: Woeste
authors.forename: Anna S
authors.initials: AS
authors.lastname: Fahrion
authors.forename: Marcus G
authors.initials: MG
authors.lastname: Doherr
authors.forename: Elisabeth
authors.initials: E
authors.lastname: grosse Beilage
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001428:Bacterial Vaccines / Q000276:immunology; D003430:Cross-Sectional Studies; D005260:Female; D008297:Male; D045705:Mycoplasma hyopneumoniae; D045729:Pneumonia of Swine, Mycoplasmal / Q000517:prevention & control*; D012307:Risk Factors; D013552:Swine; D014886:Weaning
chemical_list: D000900:Anti-Bacterial Agents; D001428:Bacterial Vaccines