title: Prevalence of Chlamydial Infections in Fattening Pigs and Their Influencing Factors.
abstract: Chlamydial infections in pigs are associated with respiratory disease, diarrhea, conjunctivitis and other pathologies. The aim of this study was to define the prevalence of Chlamydiaceae in Swiss fattening pigs by applying sensitive and specific detection methods and to correlate prior antibiotic treatment and farm related factors with differences in prevalence. Conjunctival and fecal swabs were collected from 636 pigs in 29 Swiss fattening pig farms with and without antibiotic treatment, at the beginning and the end of the fattening period. The swabs were screened by real-time PCR for Chlamydiaceae. For the chlamydial detection and species-identification, a DNA-microarray analysis was performed. All farms were positive for Chlamydiaceae with 94.3 and 92.0% prevalence in fecal swabs as well as 45.9 and 32.6% in conjunctival swabs at the first and second time points, respectively. Antibiotic treatment could not clear the infection on herd level. Potential contact with wild boars was a significant risk factor, while hygiene criteria did not influence chlamydial prevalence. A correlation of chlamydial positivity to diarrhea, but not to conjunctivitis was evident. Chlamydia suis was the predominant species. Mixed infections with C. suis and C. pecorum were common, with a substantial increase in C. pecorum positivity at the end of the fattening period, and this finding was associated with ruminant contact. C. abortus was detected in one conjunctival swab. In this study, C. suis inhabited the intestinal tract of nearly all examined pigs, implying a long-term infection. C. pecorum was also common and might be transmitted to pigs by ruminants.
authors.affiliation: Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.|Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Karolin
authors.initials: K
authors.lastname: Hoffmann
authors.affiliation: Department of Farm Animals, Division of Swine Medicine, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Franziska
authors.initials: F
authors.lastname: Schott
authors.affiliation: DIMES, Microbiology, University of Bologna, Bologna, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Donati
authors.affiliation: Department of Veterinary Medical Sciences, University of Bologna, Ozzano Emilia (BO), Italy.
authors.forename: Antonietta
authors.initials: A
authors.lastname: Di Francesco
authors.affiliation: Department for Farm Animals, Section for Herd Health, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Hässig
authors.affiliation: Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.|Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Wanninger
authors.affiliation: Department of Farm Animals, Division of Swine Medicine, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Xaver
authors.initials: X
authors.lastname: Sidler
authors.affiliation: Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors.forename: Nicole
authors.initials: N
authors.lastname: Borel
mesh_terms: D000818:Animals; D002690:Chlamydia Infections / Q000453:epidemiology / Q000382:microbiology* / Q000662:veterinary; D002693:Chlamydiaceae / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D007422:Intestines / Q000382:microbiology; D008297:Male; D034421:Sus scrofa