Characterization of Equine Parvovirus in Thoroughbred Breeding Horses from Germany

Abstract

An equine parvovirus-hepatitis (EqPV-H) has been recently identified in association with equine serum hepatitis, also known as Theiler’s disease. The disease was first described by Arnold Theiler in 1918 and is often observed with parenteral use of blood products in equines. However, natural ways of viral circulation and potential risk factors for transmission still remain unknown. In this study, we investigated the occurrence of EqPV-H infections in Thoroughbred horses in northern and western Germany and aimed to identify potential risk factors associated with viral infections. A total of 392 Thoroughbreds broodmares and stallions were evaluated cross-sectionally for the presence of anti-EqPV-H antibodies and EqPV-H DNA using a luciferase immunoprecipitation assay (LIPS) and a quantitative PCR, respectively. In addition, data regarding age, stud farm, breeding history, and international transportation history of each horse were collected and analysed. An occurrence of 7% EqPV-H DNA positive and 35% seropositive horses was observed in this study cohort. The systematic analysis of risk factors revealed that age, especially in the group of 11–15-year-old horses, and breeding history were potential risk factors that can influence the rate of EqPV-H infections. Subsequent phylogenetic analysis showed a high similarity on nucleotide level within the sequenced Thoroughbred samples. In conclusion, this study demonstrates circulating EqPV-H infections in Thoroughbred horses from central Europe and revealed age and breeding history as risk factors for EqPV-H infections.

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

“…Furthermore, we observed low genetic variability and high conservation between sequences from this study and previously published sequences from USA [2,14], Canada [15], China [17,18], Europe [14,30], and New Zealand [14]. Importantly, high similarity and conservation was also observed within sequences obtained from samples over the course of several years (e.g., horse 6 and 15).…”

Equine parvovirus hepatitis

“…Recently, all 12 publicly available complete coding sequences (CDS) of the species Ungulate copiparvovirus 6 —obtained in China and the United States—were compared with the CDS of four Austrian variants and found to be closely related 33 . The genetic diversity of the NS and VP genes appears to be low among different EqPV‐H variants in the United States, China, Canada, New Zealand, Italy, and Germany, indicating high conservation and low genetic variability of variants circulating globally 16,25,32,35,37 . Eleven years after the first outbreak of Theiler's disease on a farm in Canada, the same partial NS1 sequence was obtained from a horse that died of Theiler's disease 8 weeks after arrival on the farm.…”

“…Investigations have not yielded any evidence of viral transmission in utero 21,35 . However, 19/24 foals that were EqPV‐H‐negative at birth became infected within their first 7‐10 months of life 21 .…”

Tropism, pathology, and transmission of equine parvovirus-hepatitis

“…Equine parvovirus-hepatitis (EqPV-H) was first described in 2018 in a case of Theiler's disease, a form of acute hepatic necrosis [1]. In the United States, China, and Germany, EqPV-H has an estimated viremia prevalence of 2.9-17%, with 54% prevalence on farms where Theiler's disease was recently documented [1][2][3][4][5][6]. EqPV-H infection is closely linked to both Theiler's disease and subclinical hepatitis [2,7].…”