ARS | Publication request: FATAL NON-NEUROLOGICAL VASCULOTROPIC MULTISYSTEMIC EHV-1 INFECTION IN EQUIDAE

Submitted to: Veterinary Pathology
Publication Type: Abstract Only
Publication Acceptance Date: December 3, 2000
Publication Date: N/A

Technical Abstract: EHV-1 fatal non-neurological multisystemic prominently vasculotropic Equine Herpesvirus 1 (EHV-1) infection was identified in two young adult female horses, one (case 1, FDP) and two-year-old respectively (case 2, ANH) and in an adult zebra stallion (case 3, ASB). All three animals suffered short illnesses, severe hydrothorax with pulmonary edema, vasculitis with EHV-1 antigen (EHV-1 Ag) within endothelial cells and circulating monocytes. In case 1, additional gross lesions were prominent laryngeal lymphoid follicles and congestion and edema of the dorsal third ventricle choroid plexus. There was vasculitis, hemorrhage and edema in the lungs and dorsal third ventricle choroid plexus, as well as mild intestinal crypt necrosis. EHV-1 antigen was also identified within dendritic-like cells of the pharyngeal lymphoid follicles, pharyngeal glandular epithelium, and crypt enterocytes. In case 2, the vascular involvement was particularly prominent within the liver. In case 3 there was also multifocal necrotizing rhinitis, with EHV-1 Ag in epithelial cells, endothelial cells and intravascular leucocytes of the nasal mucosa lung, and reproductive tract with infected Leydig cells and germinal epithelium. Viral inclusions were rare in case 1. EHV-1 infection was also identified with virus isolation (cases 2 and 3), PCR (cases 1 and 3) and electron microscopy (case 1). This novel fatal form of EHV-1 infection, which may be under diagnosed and resembles other equine viral vasculitides, should be always considered and included in the possible EHV-1 manifestations. Part of this information has been published in J Vet Diagn Invest. 6(4):493-6, 1994 (ANH) and J Comp Pathol 119 (4):485-93, 1998 (ASB).