Experimental infection with Yersinia pseudotuberculosis in European brown hare (Lepus europaeus, Pallas)

Filippo Fratini; Ranieri Verin; Valentina V Ebani; Cecilia Ambrogi; Fabrizio Bertelloni; Barbara Turchi; Alessandro Poli; Domenico Cerri

doi:10.1016/j.apjtm.2017.03.008

Experimental infection with Yersinia pseudotuberculosis in European brown hare (Lepus europaeus, Pallas)

Asian Pac J Trop Med. 2017 Mar;10(3):285-291. doi: 10.1016/j.apjtm.2017.03.008. Epub 2017 Mar 6.

Authors

Filippo Fratini¹, Ranieri Verin², Valentina V Ebani³, Cecilia Ambrogi⁴, Fabrizio Bertelloni³, Barbara Turchi³, Alessandro Poli³, Domenico Cerri³

Affiliations

¹ Dipartimento di Scienze Veterinarie, Università di Pisa, Pisa, Italy. Electronic address: filippo.fratini@unipi.it.
² Dipartimento di Scienze Veterinarie, Università di Pisa, Pisa, Italy; Department of Veterinary Pathology and Public Health, Institute of Veterinary Science, University of Liverpool, UK.
³ Dipartimento di Scienze Veterinarie, Università di Pisa, Pisa, Italy.
⁴ Corpo Forestale dello Stato, Azienda Faunistica di Montefalcone, Pisa, Italy.

PMID: 28442112
DOI: 10.1016/j.apjtm.2017.03.008

Abstract

Objective: To investigate clinicopathological, bacteriological and pathological aspects of an experimental infection with Yersinia pseudotuberculosis (Y. pseudotuberculosis) in hares to verify the efficacy of serology for the in vivo diagnosis. Moreover, the pathogenicity of two Y. pseudotuberculosis strains was investigated in order to detect potential differences.

Methods: Twelve European brown hares (Lepus europaeus, Pallas) were experimentally infected per os and via conjunctival mucosae with Y. pseudotuberculosis: six subjects were infected with a strain isolated from a naturally infected hare (YpH) and six subjects with a strain isolated from a naturally infected rabbit (YpR). Two hares were used as negative controls. All animals were subjected to clinical, bacteriological and serological examinations during 9 weeks following the infection and, at the end of the control period, subjects still alive were euthanized and submitted to a complete post mortem examination.

Results: All faecal samples collected during the control period were positive for bacteriological examinations and to a PCR for the inv gene of Y. pseudotuberculosis, while only one YpH-infected hare showed a positive haemocultures. From the 2nd to the 9th week post infection (pi), serological analysis revealed specific antibodies with titers ranging from 1:10 to 1:160 in all YpH-infected and two YpR-infected subjects. All the YpH-infected and two YpR-infected hares scored positive for Y. pseudotuberculosis by means of bacteriological investigations. Grossly, suppurative multifocal lesions were detected in liver, spleen, kidney and sub-mandibular lymph nodes in both YpH- and YpR-infected hares and confirmed with histopathology. Pulmonary lesions were observed only in YpH-infected subjects. Immunohistochemistry confirmed the presence of bacterial antigen in all infected animals.

Conclusion: Results of this study revealed that YpH strain is more pathogenic for hares than the YpR strain; moreover the serological test performed in this study could be used for the diagnosis of pseudotuberculosis in hares, whereas post mortem diagnosis should be confirmed by means of bacteriological examination, PCR, histopathology and immunohistochemistry.

Keywords: Bacteriology; Hare; Histopathology; Immunohistochemistry; Serology; Yersinia pseudotuberculosis.