title: Chlamydia pecorum infections in sheep and cattle: A common and under-recognised infectious disease with significant impact on animal health.
abstract: There is a growing recognition that infections of livestock by the obligate intracellular bacterium, Chlamydia pecorum, are more widespread than was previously thought. A range of diseases have been associated with this pathogen, with the most important manifestations including infectious arthritis, infertility, enteritis, reduced growth rates, mastitis, and pneumonia. C. pecorum infections have also been associated with sub-clinical disease, highlighting our lack of knowledge about its true economic impact on livestock producers. Diagnosis of C. pecorum infection is based on clinical findings, serology and histopathology, which are not necessarily implemented in subclinical or early stages of infection, thus potentially contributing to under-diagnosis and under-reporting of infections associated with this bacterium. Recent molecular epidemiology studies have revealed that C. pecorum is genetically diverse and that there may be an association between certain strains and disease in sheep and cattle. Antimicrobial treatment of affected animals has questionable efficacy, justifying development of chlamydia vaccines for livestock. This review summarises current knowledge of the prevalence and impact of C. pecorum infections in sheep and cattle and provides an update on attempts to improve detection, management and treatment of infections by this important obligate intracellular pathogen.
authors.affiliation: Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia; Central West Local Land Services, Dubbo, NSW, Australia.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Walker
authors.affiliation: State Veterinary Diagnostic Laboratory, Elizabeth Macarthur Agricultural Institute, Menangle, NSW, Australia.
authors.forename: Effie J
authors.initials: EJ
authors.lastname: Lee
authors.affiliation: Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Timms
authors.affiliation: Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia. Electronic address: apolking@usc.edu.au.
authors.forename: Adam
authors.initials: A
authors.lastname: Polkinghorne
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000382:microbiology*; D002690:Chlamydia Infections / Q000662:veterinary*; D015995:Prevalence; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology / Q000382:microbiology*
keywords: Arthritis; Bovine; Chlamydia pecorum; Enteritis; Ovine