Vascular lesions in a young dairy heifer with BVDV

Amanda Mansz, Emily Brouwer

Animal Health Laboratory, University of Guelph, Guelph, ON.

AHL Newsletter 2022;26(2):10.

Following the death of an 8-month-old Holstein who had been repeatedly treated for a three-month-long history of pneumonia, a range of formalin-fixed and fresh tissues were submitted to the AHL.  Fixed tissues were processed for histopathology and fresh tissues were forwarded for the bovine respiratory viral panel (including PCR for Bovine herpesvirus 1, Bovine parainfluenza virus 3, Bovine respiratory syncytial virus) and Bovine viral diarrhea virus (BVDV) real-time PCR.

Various test methods, including virus neutralization, PCR and immunohistochemistry (IHC), are available for detecting BVDV in both acutely-infected and persistently-infected (PI) animals on an individual or herd level.  In this case, the real-time PCR test for BVDV type I was positive (Ct of 28.7; vaccine status unknown) and there was strong positive detection of BVDV antigen by immunohistochemical staining in various tissues including lung, heart, kidney, and liver.  Histological lesions of vasculitis with a mild mononuclear cell infiltrate in multiple organs also supported a diagnosis of BVDV infection.  A surprising and interesting microscopic feature in this case was the unusual appearance of several arteries within the myocardium (Fig. 1A).  These arteries had a “renal glomerulus-like” appearance with occlusive vascular wall thickening and hypercellularity.  Immunohistochemical staining for viral antigen was also detected within the cells forming these vascular lesions (Fig. 1B).  PCR results for the bovine respiratory panel viruses were negative.

A single case report has been published describing similar vascular lesions in myocardial and adrenal tissue in a 2-year-old PI steer as a potential result of chronic BVDV infection (1).  The paper describes an intraluminal proliferation of partially occlusive “glomerulus-like” spindle cells confirmed to be of endothelial and smooth muscle origin by IHC.  Many of these spindle-shaped cells also had positive immunoreactivity for BVDV antigen. 

Figure 1. Vascular lesions in the myocardium.  A. Arterial “glomerulus-like” appearance with occlusive vascular wall thickening and hypercellularity.  H&E stain.  B. Positive immunostaining for BVDV.  IHC

Although there are no published data definitively confirming BVDV as causation for this type of vasculopathy, the similarities between these two cases of BVDV-infected cattle present an interesting comparison.  

For more information, see AHL LabNote 1: Summary of bovine viral diarrhea virus (BVDV) testing at the AHL.   AHL

Reference

1. Breshears MA, et al. Systemic reactive angioendotheliomatosis-like syndrome in a steer presumed to be persistently infected with bovine viral diarrhea virus. Vet Pathol 2008; 45(5):645-649.