title: Intratracheal infection as an efficient route for testing vaccines against Chlamydia abortus in sheep.
abstract: Pregnant ewes have been widely used to test vaccines against Chlamydia abortus. However, this model entails many disadvantages such as high economic costs and long periods of pregnancy. The murine model is very useful for specific studies but cannot replace the natural host for the later stages of vaccine evaluation. Therefore, a non-pregnant model of the natural host might be useful for a vaccine trial to select the best vaccine candidates prior to use of the pregnant model. With this aim, two routes of infection were assessed in young non-pregnant sheep, namely, intranasal (IN) and intratracheal (IT). In addition, groups of non-vaccinated sheep and sheep immunised with an inactivated vaccine were established to investigate the suitability of the model for testing vaccines. After the experimental infection, isolation of the microorganism in several organs, with pathological and immunohistochemical analyses, antibody production assessment and investigation by PCR of the presence of chlamydia in the vagina or rectum were carried out. Experimental IT inoculation of C. abortus induced pneumonia in sheep during the first few days post-infection, confirming the suitability of the IT route for testing vaccines in the natural host. The course of infection and the resulting pathological signs were less severe in vaccinated sheep compared with non-vaccinated animals, demonstrating the success of vaccination. IN infection did not produce evident lesions or demonstrate the presence of chlamydial antigen in the lungs and cannot be considered an appropriate model for testing vaccines.
authors.affiliation: Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Álvarez
authors.affiliation: Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Salinas
authors.affiliation: Departamento de Anatomía y Anatomía Patológica Comparadas, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain.
authors.forename: A J
authors.initials: AJ
authors.lastname: Buendía
authors.affiliation: Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Ortega
authors.affiliation: Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain.
authors.forename: L
authors.initials: L
authors.lastname: del Río
authors.affiliation: Departamento de Anatomía y Anatomía Patológica Comparadas, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Sánchez
authors.affiliation: Departamento de Anatomía y Anatomía Patológica Comparadas, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Navarro
authors.affiliation: Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain.
authors.forename: M C
authors.initials: MC
authors.lastname: Gallego
authors.affiliation: Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Murcia-Belmonte
authors.affiliation: Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Cuello
authors.affiliation: Departamento de Sanidad Animal, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, Spain. Electronic address: mrcaro@um.es.
authors.forename: M R
authors.initials: MR
authors.lastname: Caro
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D001428:Bacterial Vaccines / Q000008:administration & dosage*; D002689:Chlamydia; D002690:Chlamydia Infections / Q000517:prevention & control / Q000635:transmission / Q000662:veterinary*; D061387:Chlamydial Pneumonia / Q000517:prevention & control; D004195:Disease Models, Animal; D009668:Nose Diseases / Q000276:immunology / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology / Q000517:prevention & control*; D014133:Tracheal Diseases / Q000276:immunology / Q000517:prevention & control; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D015164:Vaccines, Inactivated
keywords: Chlamydia abortus; Enzootic abortion; Intranasal infection; Intratracheal infection; Pneumonia; Sheep