First description of a herpesvirus infection in genus Lepus.

During the necropsies of Iberian hares obtained in 2018/2019, along with signs of the nodular form of myxomatosis, other unexpected external lesions were also observed. Histopathology revealed nuclear inclusion bodies in stromal cells suggesting the additional presence of a nuclear replicating virus. Transmission electron microscopy further demonstrated the presence of herpesvirus particles in the tissues of affected hares. We confirmed the presence of herpesvirus in 13 MYXV-positive hares by PCR and sequencing analysis. Herpesvirus-DNA was also detected in seven healthy hares, suggesting its asymptomatic circulation. Phylogenetic analysis based on concatenated partial sequences of DNA polymerase gene and glycoprotein B gene enabled greater resolution than analysing the sequences individually. The hare' virus was classified close to herpesviruses from rodents within the Rhadinovirus genus of the gammaherpesvirus subfamily. We propose to name this new virus Leporid gammaherpesvirus 5 (LeHV-5), according to the International Committee on Taxonomy of Viruses standards. The impact of herpesvirus infection on the reproduction and mortality of the Iberian hare is yet unknown but may aggravate the decline of wild populations caused by the recently emerged natural recombinant myxoma virus.

Detection of rabbit Haemorrhagic disease virus 2 during the wild rabbit (Oryctolagus cuniculus) eradication from the Berlengas archipelago, Portugal.

BACKGROUND: In the regular wildlife monitoring action carried out in the summer of the past few years at the Berlenga Island, wild rabbits (Oryctolagus cuniculus) have been repeatedly found dead. However, the origin of those deaths was never investigated. Our aim was to investigate the cause of death of 11 rabbits collected between April and May 2016. RESULTS: While screening samples from rabbit carcasses for the major viral rabbit pathogens, five tested positive to RHDV2 but all were negative for RHDV and myxoma virus (MYXV). For six RHDV2-negative specimens, emaciation and parasitism were considered the most probable cause of death. Lesions identified in the RHDV2-positive rabbits included non-suppurative diffuse hepatic necrosis and pulmonary lesions varying from congestion and oedema of the lungs to interstitial pneumonia. Sequencing analysis of the vp60 gene obtained from two specimens showed identical vp60 sequences. Comparison with other known RHDV2 strains from public databases through BLAST analysis revealed a closer similarity with strains from Alentejo collected during 2013. Maximum Likelihood and Bayesian phylogenetic analysis showed that the 2016 strains from the archipelago have a higher resemblance with a group of strains mostly collected in the South of Portugal between 2013 and 2014. CONCLUSION: The results suggest that RHDV2 may have been introduced on the Berlenga Island a few years ago, having evolved separately from mainland strains due to insularity.