Clinical Course of Infection and Cross-Species Detection of Equine Parvovirus-Hepatitis

Birthe Reinecke,Yannick Brüggemann,Wolfgang Baumgärtner,Daniel Todt,Alan Guthrie,Christina Puff,Jessika-M V Cavalleri,Mara Klöhn,Alexander Stang,Katja Koeppel,Volker Kinast,Ursula Groner,Madeleine De Le Roi,Eike Steinmann,Marcha Badenhorst

doi:10.3390/v13081454

Abstract

Since its first discovery by Arnold Theiler in 1918, serum hepatitis also known as Theiler’s disease has been reported worldwide, causing idiopathic acute hepatitis and liver failure in horses. Recent studies have suggested a novel parvovirus, named equine parvovirus hepatitis (EqPV-H), to be associated with Theiler’s disease. Despite the severity and potential fatality of EqPV-H infection, little is known about the possibility of developing chronic infections and putative cross-species infection of equine sister species. In the present longitudinal study, we employed qPCR analysis, serology, and biochemical testing as well as pathology examination of liver biopsies and sequence analysis to investigate potential chronic EqPV-H infection in an isolated study cohort of in total 124 horses from Germany over five years (2013–2018). Importantly, our data suggest that EqPV-H viremia can become chronic in infected horses that do not show biochemical and pathological signs of liver disease. Phylogenetic analysis by maximum likelihood model also confirms high sequence similarity and nucleotide conservation of the multidomain nuclear phosphoprotein NS1 sequences from equine serum samples collected between 2013–2018. Moreover, by examining human, zebra, and donkey sera for the presence of EqPV-H DNA and VP1 capsid protein antibodies, we found evidence for cross-species infection in donkey, but not to human and zebra. In conclusion, this study provides proof for the occurrence of persistent EqPV-H infection in asymptomatic horses and cross-species EqPV-H detection in donkeys.

Highlights

Serum hepatitis known as Theiler’s disease (TD) is the most common cause of acute and potentially life-threatening viral hepatitis in horses
Not all horses could be sampled at every date as some had to be euthanized and new ones were introduced into the groups
We tested all samples for equine parvovirus hepatitis (EqPV-H) by quantitative polymerase chain reaction (qPCR) and luciferase immunoprecipitation systems (LIPS) assay for either the presence of viral DNA or anti-VP1 antibodies in 2019 (Figure 1)

Summary

Introduction

Serum hepatitis known as Theiler’s disease (TD) is the most common cause of acute and potentially life-threatening viral hepatitis in horses. The disease was first described by Arnold Theiler in 1918, who observed acute liver atrophy and diffuse hepatic necrosis following the administration of a combination of live virus and convalescent equine antiserum in horses from South Africa [1]. Outbreaks of TD have been described worldwide in conjunction with a vast variety of equine-derived blood products including tetanus antitoxin, botulinum antitoxin, antiserum against Streptococcus equi as well as pregnant mare’s serum, and equine plasma [1,2,3,4,5]. Subsequent infection experiments in two healthy mares inoculated with commercial TAT that were qPCR positive for EqPV-H DNA confirmed EqPV-H as the pathogenic agent of idiopathic acute hepatitis and liver failure in horses a.k.a. Theiler’s disease [2,12,13]

Methods

Results

Conclusion