First detected case of rabbit Haemorrhagic disease virus 2 (RHDV2) in the Irish hare (Lepus timidus hibernicus)

Abstract

Background Rabbit haemorrhagic disease virus (RHDV) is a Lagovirus, a subgroup of the family Caliciviridae. RHDV2 is a variant first described in France in 2010, and has since spread globally. It has been reported in several Lagomorph species (rabbits, hares, and their relatives) as well as other mammals including voles and shrews. The disease has raised international concerns for its potential impact on population abundance trajectories, particularly as 25% of Lagomorphs are currently Red-Listed by the International Union for the Conservation of Nature (IUCN). The Irish hare (Lepus timidus hibernicus) is a subspecies of the mountain hare, L. timidus, and is endemic to Ireland, making it an Evolutionarily Significant Unit of intrinsic value. Case presentation The first case of RHDV2 was detected in a wild Irish hare in July 2019. The individual exhibited atypical neurological behaviour (running in circles) prior to death. On necropsy, pink tinged foam was seen in the trachea and congestion was noted in the lungs, but there was no evidence of haemorrhages in any other organ. Both the liver and spleen were tested by reverse transcription real time qPCR confirming high levels of RHDV2 RNA. Histopathology confirmed multifocal necrotising hepatitis. Conclusion The Irish hare is susceptible to RHDV2 infection. Further investigation is warranted to explore the clinical, epidemiological, and population biology implications.

Rabbit Haemorrhagic Disease Virus 2 (RHDV2; GI.2) in Ireland Focusing on Wild Irish Hares (Lepus timidus hibernicus): An Overview of the First Outbreaks and Contextual Review

“…All cases were diagnosed using reverse transcription real-time–polymerase chain reaction (RT-qPCR); no sequencing was undertaken. Additional details of the laboratory procedures can be found in Kennedy et al [ 12 ].…”

“…hibernicus ), Cape ( L. capensis subsp. mediterraneus ), Iberian ( L. granatensis ) and Italian ( L. corsicanus ) hares, black-tailed jackrabbit ( L. californicus ), and antelope jackrabbit ( L. alleni ) [ 9 , 10 , 11 , 12 , 13 , 14 ]. RHDV2 has been reported to infect several Sylvilagus (cottontail) species also, including eastern ( S. floridanus ) , desert ( S. audubonii ), and mountain ( S. nuttallii ) cottontails [ 13 , 15 , 16 ].…”

“…Seizures may be more frequent near death [ 20 ]. In the small number of cases where clinical signs have been described before death, these included epistaxis, apathy/depression, anorexia, and neurological signs such as ataxia and circling [ 12 ]. Pathologically, the infection is characterised by necrotising hepatitis, with gross morphological impacts on liver and spleen, haemorrhage in other tissues, and occasionally jaundice (icterus).…”

“…In an Irish context, the rabbit is an important non-native but naturalised prey species (introduced during the 12th century) for several native and naturalised predators, e.g., the Irish stoat ( Mustela ermine hibernica ), fox ( Vulpes vulpes ), and buzzard ( Buteo buteo ; [ 70 ]), but the extent of food web impacts from rabbit declines due to RHD remain unknown. The potential ecological impacts resulting from disease in the Irish hare [ 12 ] remain unknown, but like the rabbit, it is also a key prey species for many predators, including reintroduced golden eagles ( Aquila chrysaetos) .…”

Development and Evaluation of a Duplex Lateral Flow Assay for the Detection and Differentiation between Rabbit Haemorrhagic Disease Virus Lagovirus europaeus/GI.1 and /GI.2

“…), several cottontail rabbit species (Sylvilagus spp.) and other native American lagomorphs, in which it produces similar lesions [11][12][13][14][15][16][17][18]. It has also been identified in some non-lagomorphs [19,20].…”