Viraemic frequencies and seroprevalence of non-primate hepacivirus and equine pegiviruses in horses and other mammalian species.

The research article investigates the prevalence and clinical features associated with non-primate hepacivirus (NPHV) and equine pegivirus (EPgV) infections in horses and other mammals. The study did not find evidence of these viral infections contributing to liver disease in horses, though both infections were found to be widespread among the study’s horse population.

Research Methodology

• The researchers studied two relatively new identified viruses from the Flaviviridae family – non-primate hepacivirus (NPHV) and equine pegivirus (EPgV).
• Large cohorts of various mammalian species, including horses, donkeys, dogs, cats, non-human primates, and humans, were sampled to evaluate the prevalence of NPHV, EPgV, and Theiler’s disease associated virus (TDAV).
• The animals were both tested for current viraemia (the presence of viruses in the blood) and serological assays for past exposure.

Main Findings

• The researchers found that antibodies for NPHV were detected in 43% of 328 horses. However, viraemia by PCR was only confirmed in three of these horses.
• All five horses that were stablemates of a viraemic horse were seropositive, as was a dog on the same farm.
• Except for the previously mentioned dog, all other species tested negative for NPHV antibodies and viraemia.
• EPgV-specific antibodies were detected in 66.5% of horses, including 10 out of the 12 horses that had EPgV viraemia. All donkey samples were negative for both EPgV antibodies and RNA.
• All horse and donkey samples tested negative for TDAV RNA.
• The researchers found no evidence indicating an association between active NPHV and EPgV infections with hepatopathy (liver disease), by comparing viraemia frequencies in horses with and without liver disease.

Conclusions

• The study demonstrates that NPHV and EPgV infections are widespread and enzootic (prevalent in certain populations but not common to all) among the horse population.
• The research also confirms that both NPHV and potentially EPgV have higher frequencies of viral clearance than HCV and HPgV infections in humans. This implies that horses have a more effective immune response in clearing these viruses compared to humans who are infected with related viruses.