Hepatitis viruses: prevalence of equine parvovirus-hepatitis virus and equine hepacivirus in France and Australia

Christine Fortier (1, 2) , Charlie El-Hage (3) , Erika Hue (2, 1) , Gabrielle Sutton (1, 2) , Christel Marcillaud Pitel (4) , K. Jeffers (3) , N. Bamford (3) , Elise Oden (1) , Romain Paillot (1, 2, 5) , C. Hartley (3) , James Gilkerson (3) , Stéphane Pronost (2, 1)

1 LABÉO - LABÉO, Pôle d’analyses et de recherche de Normandie
2 BIOTARGEN - Biologie, génétique et thérapies ostéoarticulaires et respiratoires
3 University of Melbourne
4 RESPE - Réseau d'Epidémio-Surveillance en Pathologie Équine
5 School of Equine and Veterinary Physiotherapy

Background: Recent identification of viruses considered responsible for Theiler’s disease (acute hepatitis) in horses include equine parvovirus-hepatitis (EqPV-H) and the most likely of several flaviviruses, equine hepacivirus (EqHV). Both of these viruses have now been detected in North America, Asia, and Europe. Objectives: To determine the prevalence of EqPV-H and EqHV in French and Australian horses and to analyse their respective phylogenetic relationships. Study design: Cross-sectional. Methods: Clinically documented sera from 188 Australian horses and 259 French horses collected between 2016-2019 were analysed. qPCRs validated according to the NF47-600 standard were used to detect EqPV-H and EqHV in sera. Sequencing for phylogenetic analysis was performed on two NS1 fragments (516 nt and 587 nt) for EqPV-H and one NS5B fragment (308 nt) for EqHV. A phylogenic network was built using a Median Joining Network algorithm. Results: 1) EqPV-H: 12/259 (4.6%) and 6/188 (3.2%) samples from French and Australian horses were positive, respectively. Viral loads ranged from 2.3e05 to 6.5e05 copies genome/ml. 2) EqHV: 5/259 (1.9%) and 21/188 (11.2%) samples from French and Australian horses were positive, respectively. Viral loads ranged from 6.1e04 to 1.4e08 copies genome/ml. Both EqPV-H (587 nt fragment) and EqHV phylogenetic analyses showed that Australian strains were clustered, while overall distribution was more heterogenous in French horses. Main limitations: The study population is built by accessing laboratory submissions and potentially biased. The 516 nt NS1 fragment could not be sequenced. Conclusions: This is the first report of EqPV-H detection in both Australian and French horses. The EqPV-H prevalence was similar between the two countries (p-value=0.6) although phylogenetic differences were observed between the two populations. This is also the first reported detection of EqHV in Australian horses, with a higher prevalence when compared with French horses.

Domaines: Médecine vétérinaire et santé animale

Christine Fortier, Charlie El-Hage, Erika Hue, Gabrielle Sutton, Christel Marcillaud Pitel, et al.. Hepatitis viruses: prevalence of equine parvovirus-hepatitis virus and equine hepacivirus in France and Australia. 11th International Equine Infectious Diseases Conference, Sep 2021, Online, France. pp.68, ⟨10.1111/evj.103_13495⟩. ⟨hal-03362318⟩