Chronic Leptospirosis in a Breeding Bull: A Case Report

Abstract

Leptospirosis is a (re-)emerging and global zoonotic disease. Given the complex host-pathogen interaction and the numerous environmental risk factors related to the transmission, a One Health approach to both disease prevention and control is needed. Occurring at the human-cattle-environment interfaces, bovine leptospirosis represents a zoonotic risk for the professionals in the field, besides being a potential cause of significant economic losses due to the bovine reproductive disorders. Although climatic change is a potential factor in exacerbating the risk of leptospirosis in Europe, this disease remains largely neglected, with several knowledge gaps in research, investigations, and diagnosis of bovine genital leptospirosis syndrome across the continent. The present report describes the results of the diagnostic investigations on a case of chronic bovine leptospirosis in a breeding bull. Following the seroconversion to Leptospira Sejroe var Hardjo after the arrival of the animal in a quarantine facility, a monitoring plan including both serological/molecular analyses and a therapeutic protocol was undertaken. The bull exhibited a persistent seroconversion and a repeated positivity for Leptospira to real-time PCR in urine samples, indicative of a chronic shedder pattern. This report emphasizes the diagnostic and management challenges in the context of such a complex but frequently overlooked disease.

Keywords: Leptospira; One Health; bovine genital leptospirosis; cattle; leptospirosis.

Figure 1

Serological monitoring plan, PCR screening plan and antibiotic therapies. First antibiotic therapy: intramuscular administration of oxytetracycline cloridate (Oxtra Mv 10, FATRo S.p.A., Ozzano dell’Emilia (BO), Italy—3 days). Second antibiotic therapy: subcutaneous administration of ceftiofur (Ceftionil, Virbac S.r.l., Milano (MI), Italy—6 days). The MAT was performed on 4 serum samples collected on days 4, 29, 49, and 85.

Figure 2

Kidney, rare, multifocal, irregularly round, grey lesions on the surface (arrowheads).

Figure 3

Kidney, scattered foci of chronic interstitial nephritis (arrows) mainly composed of lymphocytes and plasma cells (hematoxylin and eosin, 10×).

Figure 4

Testicle, mild multifocal chronic interstitial orchitis (arrowheads) composed of histiocytes, lymphocytes and fewer plasma cells and neutrophils with severe diffuse seminal atrophy (asterisks) and mild peritubular/interstitial fibroplasia (arrow) (hematoxylin and eosin, 20×).