title: Prevalence of intestinal chlamydial infection in pigs in the midwest, as determined by immunoperoxidase staining.
abstract: OBJECTIVE
  To determine prevalence of intestinal chlamydial infection in pigs and to compare prevalence of diarrhea in infected pigs with that in noninfected pigs to evaluate the importance of Chlamydia sp as causes of diarrhea in pigs. ANIMALS AND PROCEDURES: Intestines from 351 sick pigs submitted to 2 veterinary diagnostic laboratories and from 96 healthy pigs that were part of an Escherichia coli susceptibility study were examined by immunoperoxidase staining for chlamydial antigen. The proportion of Chlamydia-infected pigs in each group was calculated and compared. The proportion of Chlamydia-infected pigs with diarrhea was compared with the proportion of noninfected pigs with diarrhea.
  
  
  RESULTS
  15% of the sick and healthy pigs were infected with Chlamydia sp. Prevalence of diarrhea was equal between infected and noninfected pigs. Chlamydia sp were the third most common pathogens identified, and prevalence of chlamydial infection increased after 3 weeks of age.
  
  
  CONCLUSIONS
  Intestinal chlamydiosis is common in commercial pigs, but most, if not all, infections are subclinical Without collaborative evidence, simply identifying Chlamydia sp in feces or the intestinal tract of pigs with enteritis or diseases of other organ systems should not be considered proof that the organism caused the clinical signs of disease.
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan 66506, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Nietfeld
authors.forename: P
authors.initials: P
authors.lastname: Leslie-Steen
authors.forename: D H
authors.initials: DH
authors.lastname: Zeman
authors.forename: D
authors.initials: D
authors.lastname: Nelson
mesh_terms: D000818:Animals; D002689:Chlamydia / Q000302:isolation & purification; D002690:Chlamydia Infections / Q000453:epidemiology / Q000662:veterinary*; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary; D007410:Intestinal Diseases / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D007413:Intestinal Mucosa / Q000382:microbiology; D007421:Intestine, Small / Q000382:microbiology; D015146:Midwestern United States / Q000453:epidemiology; D015995:Prevalence; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology*