title: Is the horse a reservoir or an indicator of Coxiella burnetii infection? Systematic review and biomolecular investigation.
abstract: The role of the horse in Coxiella burnetii infection has not been defined. Accordingly, a twofold approach was taken to further our knowledge on this topic: (1) conduct a systematic review of the literature to establish available evidence of C. burnetii infection in the horse; (2) undertake a biomolecular investigation of 122 cases of equine abortion, stillbirth and neonatal foal death, for the presence of C. burnetii using a PCR test targeting the IS1111 gene of C. burnetii. A review of the literature turned up seven studies that identified C. burnetii DNA in equine specimens, especially aborted fetuses, while an additional 34 studies sought to determine seroprevalence of the infection in the horse. A meta-analytical approach was taken to calculate a pooled mean seroprevalence in equines based on published studies. A seroprevalence of 15.8% (95% confidence interval: 9.6-23.0%) was obtained. This figure is comparable to those previously reported in other species, especially ruminants. None of the 122 cases of equine abortion, stillbirth or neonatal foal death were positive for C. burnetii DNA. C. burnetii has rarely been looked for in equine specimens in previous studies. Cases of equine abortion should be comprehensively investigated to assess the risk of abortion in a pregnant mare infected with C. burnetii. Consideration should also be given to the possible role of the horse as a source of the organism for other animal species including humans.
authors.affiliation: Department of Veterinary Medicine, University of Perugia, Via S. Costanzo 4, 06126 Perugia, Italy. Electronic address: marialuisa.marenzoni@unipg.it.
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Marenzoni
authors.forename: Valentina
authors.initials: V
authors.lastname: Stefanetti
authors.forename: Paola
authors.initials: P
authors.lastname: Papa
authors.forename: Patrizia
authors.initials: P
authors.lastname: Casagrande Proietti
authors.forename: Annalisa
authors.initials: A
authors.lastname: Bietta
authors.forename: Mauro
authors.initials: M
authors.lastname: Coletti
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Passamonti
authors.forename: Klaus
authors.initials: K
authors.lastname: Henning
mesh_terms: D037881:Aborted Fetus / Q000382:microbiology; D000034:Abortion, Veterinary / Q000382:microbiology; D000818:Animals; D000831:Animals, Newborn / Q000382:microbiology; D016997:Coxiella burnetii / Q000235:genetics / Q000502:physiology*; D004269:DNA, Bacterial / Q000097:blood; D005260:Female; D006734:Horse Diseases / Q000453:epidemiology / Q000382:microbiology*; D006736:Horses; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011247:Pregnancy; D011778:Q Fever / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D016036:Seroepidemiologic Studies
chemical_list: D004269:DNA, Bacterial
keywords: Abortion; Coxiella burnetii; Horse; PCR; Q fever