Rabbit hemorrhagic disease virus (RHDV) is a type of Calicivirus that affects both wild and domestic European rabbits (Oryctolagus cuniculus). This disease first appeared in Europe during the 1980s and led to widespread outbreaks with high mortality rates among rabbits. RHDV primarily affects Oryctolagus cuniculus, with adult rabbits experiencing mortality rates ranging from 70-100%. Young rabbits become partially susceptible to the disease from the 5th week of age, and by the 8th week, they are fully susceptible. The disease is characterized by severe acute necrotizing hepatitis and hemorrhagic disease. A closely related but phylogenetically distinct virus causes a similar disease in European brown hares (Lepus europaeus), known as "European brown hare syndrome."

Source: https://rhdv2.org/what-is-rhdv2/

The decline of wild rabbit and European brown hare populations in Europe has been attributed to mortality caused by Lagoviruses. These lagomorphs play a crucial role in ecosystems, so their decline has had a significant ecological impact. The widespread outbreaks of Rabbit Hemorrhagic Disease (RHD) in the late 80s and early 90s in Western Europe resulted in a drastic reduction (50% to 80%) and fragmentation of wild rabbit populations.



The newly emerged lagovirus, RVHD2, differs from classic RHDV in several ways. Firstly, it has a broader host range, causing disease not only in rabbits but also in Cape Hares and Italian hares. Additionally, it causes mortality in young rabbits under 30 days of age and has lower and more variable mortality rates.

The origin of lagoviruses, including the recently emerged RHDV2, is not yet clear. The emergence of this new lagovirus and its impact on wild rabbit populations are of concern. Furthermore, the rapid spread of RHDV2 and its potential to affect other Lagomorphs species in Europe poses a threat not only to lagomorphs but also to species that rely on them for food.