Dr Terry Mabbett reports on the outlook for British hares with rabbit haemorrhagic disease virus running rampant.

THE strong hind legs and streamlined body of the brown hare (Lepus europaeus) make this British native mammal the fastest thing on four legs here (70 km/h), but it is apparently not fast enough to outrun rabbit haemorrhagic disease virus (RHDV).

The RHDV2 variant was already killing large numbers of wild rabbits in the east of England in autumn 2018 when significant numbers of dead and dying brown hares were reported in Suffolk and Norfolk. The RHDV2 strain of rabbit haemorrhagic disease was strongly suspected.

Dr Diana Bell of the School of Biological Sciences at the University of East Anglia said either rabbit haemorrhagic disease or myxomatosis could be a possible cause. Either way, it means one or possibly both of these highly pathogenic animal viruses jumped species from European rabbit (Oryctolagus cuniculus) to the brown hare. The disease normally affects rabbits, but is known to have jumped to European brown hares in Italy, Spain, France and Australia.

British conservationists are already worried for the future of the truly native brown hare following an 80 per cent reduction in numbers over the last century, mainly due to shooting and hare coursing, but also intensification of agriculture.

The worst fears for the brown hare were realised in January 2019, after the RHDV2 strain was confirmed in dead hares in Essex and Dorset (Bell et al., 2019). The research was carried out by Dr Bell in collaboration with diagnostic laboratories in England, Scotland and Germany. Confirmation of RHDV2 in brown hares in Scotland was published shortly afterwards (Rocchi et al., 2019).

Dr Bell said: “RHDV2 is one of several pathogens we are finding in dead hares, but it is too early to say exactly what is the primary cause of the condition currently causing hare die-off. We are still collecting bodies of hares to test for other pathogens that could be contributing to the decline. The expanding data-set will allow us to map reported mortalities over time.”

Forestry Journal: Newly planted trees in Suffolk protected against rabbit and hare herbivory.Newly planted trees in Suffolk protected against rabbit and hare herbivory.

Rabbit haemorrhagic disease virus type 2 (RHDV2 or GI.2) is a calicivirus causing acute and usually fatal haemorrhagic lungs and hepatitis in lagomorphs (a member of the taxonomic order Lagomorpha, which includes rabbits and hares). RHDV2 was first identified in the United Kingdom in 2013, although retrospective sampling suggests it has been here since 2010.

Mountain hare (Lepus timidus), a crucially important component of the Scottish landscape and ecosystems, is clearly at risk, especially since the RHDV2/GI.2 strain has already been identified in mountain hares in Sweden (Neimanis et al., 2018).

With respect to browsing and bark stripping, foresters are more concerned about rabbits due to their greater numbers. However, brown hares are not completely innocent in these respects. The Forestry Commission says brown hares target trees at the establishment and thicket stages causing widespread damage.

The use of tree shelters to avoid bark stripping and browse damage by hares is required for protection of young trees at planting and beyond. Like rabbits, hares can browse from the upright hind-leg position to give them greater access to foliage.

According to Forest Research, hares may cause damage along a line of young trees up to a height of 0.7 m. Tree shelter suppliers recommend tree shelter heights of at least 0.6 m and 0.75 m to avoid damage to young trees by rabbits and hares respectively Where both present risks to young trees, foresters should err on the side of caution and select the taller tree shelter option.

If RHDV2 continues to rip through the wild rabbit population and, subsequently, native hares, will young tree protection against herbivory by lagomorphs be required here?


Bell, D. J., Davis, M.G., Barlow, A.M., Rocchi, M., Gentil, M. and Wilson, R.J. (2019) ‘Rabbit haemorrhagic disease virus type 2 in hares in England’, Vet Record Volume 184 Issue 4.

Rocchi, M., Maley, M., Dagleish, M. and Boag, B. (2019) ‘Rabbit haemorrhagic disease virus type 2 in hares in Scotland’, Vet Record Volume 185 Issue 1.

Neimanis, A.S., Ahola, H., Larsson Pettersson, U., Lopes, A.M., Abrantes, J., Zohari, S., Esteves, P.J. and Gavier-Widen, D. (2018) ‘Overcoming species barriers: an outbreak of Lagovirus europaeus GI.2/RHDV2 in an isolated population of mountain hares (Lepus timidus)’, BMC Veterinary Research 14, 367.

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