Hepatitis C virus (HCV) has a very narrow species and tissue tropism and efficiently replicates only in humans and the chimpanzee. Recently, several studies identified close relatives to HCV in different animal species. Among these novel viruses, the nonprimate hepaciviruses (NPHV) that infect horses are the closest relatives of HCV described to date. In this study, we analyzed the NPHV prevalence in northern Germany and characterized the clinical course of infection and viral tissue tropism to explore the relevance of HCV-related horse viruses as a model for HCV infection. We found that approximately 31.4% of 433 horses were seropositive for antibodies (Abs) against NPHV and approximately 2.5% carried viral RNA. Liver function analyses revealed no indication for hepatic impairment in 7 of 11 horses. However, serum gamma-glutamyl transferase (GGT) concentrations were mildly elevated in 3 horses, and 1 horse displayed even highly elevated GGT levels. Furthermore, we observed that NPHV infection could be cleared in individual horses with a simultaneous emergence of nonstructural (NS)3-specific Abs and transient elevation of serum levels of liver-specific enzymes indicative for a hepatic inflammation. In other individual horses, chronic infections could be observed with the copresence of viral RNA and NS3-specific Abs for over 6 months. For the determination of viral tissue tropism, we analyzed different organs and tissues of 1 NPHV-positive horse using quantitative real-time polymerase chain reaction and fluorescent in situ hydridization and detected NPHV RNA mainly in the liver and at lower amounts in other organs. Conclusion: Similar to HCV infections in humans, this work demonstrates acute and chronic stages of NPHV infection in horses with viral RNA detectable predominantly within the liver. (HEPATOLOGY 2015;61:447-459) G lobally, an estimated 160 million people are chronically infected with hepatitis C virus (HCV) 1 and are therefore at a high risk for developing severe liver damage, including hepatic steatosis, fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). 2 Acute HCV infection is asymptomatic in

Hepatitis C virus (HCV) displays a restricted host species tropism and only humans and chimpanzees are susceptible to infection. A robust immunocompetent animal model is still lacking, hampering mechanistic analysis of virus pathogenesis, immune control, and prophylactic vaccine development. The closest homolog of HCV is the equine nonprimate hepacivirus (NPHV), which shares similar features with HCV and thus represents an animal model to study hepacivirus infections in their natural hosts. We aimed to dissect equine immune responses after experimental NPHV infection and conducted challenge experiments to investigate immune protection against secondary NPHV infections. Horses were i.v. injected with NPHV containing plasma. Flow cytometric analysis was used to monitor immune cell frequencies and activation status. All infected horses became viremic after 1 or 2 wk and viremia could be detected in two horses for several weeks followed by a delayed seroconversion and viral clearance. Histopathological examinations of liver biopsies revealed mild, periportally accentuated infiltrations of lymphocytes, macrophages, and plasma cells with some horses displaying subclinical signs of hepatitis. Following viral challenge, an activation of equine immune responses was observed. Importantly, after a primary NPHV infection, horses were protected against rechallenge with the homologous as well as a distinct isolate with only minute amounts of circulating virus being detectable.hepatitis C virus | nonprimate hepacivirus | infection | immune protection | rechallenge H epatitis C virus (HCV) infections constitute a major global health problem with ∼130 million people being chronically infected (1). Once infected, 70-90% of individuals progress to chronicity, rendering HCV the leading cause of liver diseases, including liver fibrosis, cirrhosis, and hepatocellular carcinoma (2). HCV is a blood-borne, positive-stranded RNA virus classified to the family of Flaviviridae within the genus Hepacivirus. Seven different HCV genotypes and numerous subtypes have been described, which differ on the nucleotide level by ∼30-35% between different genotypes and maximally 30% between subtypes (3). Furthermore, within infected individuals the virus circulates as a population of closely related but distinct genomes (4). Recently, significant progress has been made regarding the treatment of HCV with the implementation of direct-acting antiviral (DAA) drugs, which can be administered as all-oral IFN-free therapeutics and should help to reduce the global burden of HCV infections (5). However, there are still many caveats, including high treatment costs and the risk of reinfection after successful therapy, which is a problem especially in patient populations with frequent exposure to HCV. Furthermore, the inadequacy of current HCV screening programs often results in late diagnosis of chronic HCV infection and subsequent proceeding to end-stage liver diseases (6). All of these challenges highlight the necessity for a prophylactic vaccine against HCV, ...

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.

Background Equine parvovirus‐hepatitis (EqPV‐H) research is in its infancy. Information regarding prevalence, geographical distribution, genetic diversity, pathogenesis and risk factors enhances understanding of this potentially fatal infection. Objectives Determining the prevalence of EqPV‐H in Austrian equids. Investigating factors increasing probability of infection, liver‐associated biochemistry parameters, concurrent equine hepacivirus (EqHV) infection and phylogenetic analysis of Austrian EqPV‐H variants. Study design Cross‐sectional study. Methods Sera from 259 horses and 13 donkeys in Austria were analysed for anti‐EqPV‐H VP1‐specific antibodies by luciferase immunoprecipitation system (LIPS) and EqPV‐H DNA by nested polymerase chain reaction (PCR). Associations between infection status, sex and age were described. Glutamate dehydrogenase (GLDH), gamma‐glutamyl transferase (GGT), bile acids and albumin concentrations were compared between horses with active infection and PCR‐negative horses. PCR targeting partial EqPV‐H NS1 was performed and phylogenetic analysis of Austrian EqPV‐H variants was conducted. Complete coding sequences (CDS) of four Austrian variants were determined by next‐generation sequencing (NGS) and compared with published sequences. Results Horses' EqPV‐H seroprevalence was 30.1% and DNA prevalence was 8.9%. One horse was co‐infected with EqHV. Significantly, higher probability of active EqPV‐H infection was identified in 16‐ to 31‐year‐old horses, compared with 1‐ to 8‐year‐old horses (P = 0.002; OR = 8.19; 95% CI = 1.79 to 37.50) and 9‐ to 15‐year‐old horses (P = 0.03; OR = 2.96; 95% CI = 1.08 to 8.17). Liver‐associated plasma parameters were not significantly different between horses with active infection and controls. Austrian EqPV‐H variants revealed high similarity to sequences worldwide. No evidence of EqPV‐H was detected in donkeys. Main limitations Equids’ inclusion depended upon owner consent. There was only one sampling point per animal and the sample of donkeys was small. Conclusions EqPV‐H antibodies and DNA are frequently detected in Austrian horses, without associated hepatitis in horses with active infection. The risk of active EqPV‐H infection increases with increasing age. Phylogenetic evidence supports close relation of EqPV‐H variants globally, including Austrian variants.

An equine parvovirus-hepatitis (EqPV-H) has been recently identified in association with equine serum hepatitis, also known as Theiler’s disease. This disease was first described by Arnold Theiler in 1918 and is often observed after applications with blood products in equines. So far, the virus has only been described in the USA and China. In this study, we evaluated the presence of EqPV-H in several commercial serum samples to assess the potential risk of virus transmission by equine serum-based products for medical and research applications. In 11 out of 18 commercial serum samples, EqPV-H DNA was detectable with a viral load up to 105 copies/mL. The same serum batches as well as three additional samples were also positive for antibodies against the EqPV-H VP1 protein. The countries of origin with detectable viral genomes included the USA, Canada, New Zealand, Italy, and Germany, suggesting a worldwide distribution of EqPV-H. Phylogenetic analysis of the EqPV-H NS1 sequence in commercial serum samples revealed high similarities in viral sequences from different geographical areas. As horse sera are commonly used for the production of anti-sera, which are included in human and veterinary medical products, these results implicate the requirement for diagnostic tests to prevent EqPV-H transmission.