23th October 2019
FAQ on RHD/RHD2 and Hare Coursing
What has happened?
During July and August twelve carcasses of dead wild rabbits and hares were submitted to the National Parks and Wildlife Service from Counties Clare, Cork, Leitrim, Offaly, Wicklow and Wexford. Post-mortem tests were then carried out in the Dept of Agriculture (DA) lab in Backweston, Co Leitrim.
Of the animal carcasses tested by DA to date 17 have been confirmed with the Rabbit haemorrhagic disease (RHD2) virus. 4 hares and 13 rabbits.
After the first positive test for RHD2 in the Irish wild hare population in July, on Friday 9th August, the Minister for Culture, Heritage and the Gaeltacht temporarily suspended the licenses it issues to the Irish Coursing Club to capture and tag hares until the extent of the disease was established. This followed the issuing of the annual coursing license covering the 2019/20 season in late July.
Following further positive test results, the Minister decided on Friday 13th September to extend the ban on netting hares. This will allow the National Parks and Wildlife Service (NPWS) have a clearer understanding of the extent, spread and implications of the RHD virus.
This decision is being reviewed on an ongoing basis.
What is RHD?
Rabbit haemorrhagic disease (RHD) was first reported in domestic (farmed) rabbits in China in 1984, killing 4 million animals within one year of its discovery. By 1986 this viral disease had been found in continental Europe and has since spread globally leading to significant mortality in wild populations of rabbits.
In 2010, a new more virulent strain of this virus (RHD2) emerged in France. It causes death within a few days of infection with sick animals having swollen eyelids, partial paralysis and bleeding from the eyes and mouth.
The virus is extremely resistant, remaining viable for up to two months in the environment. It can be passed on by direct contact, but also in faeces and urine. Infected carcasses can harbour infective virus for several months post mortem. The virus can also be transported on soil, shoes and on clothing as well as by insects. It can be killed, however, using suitable disinfectants (e.g. Virkon).
Biosecurity measures have been put in place at NPWS and OPW sites where the disease has been confirmed and NPWS Conservation Rangers continue to monitor the situation nationally.
RHD was first detected in domestic rabbits in Ireland in 2018. This summer it was confirmed in wild rabbits in Co Clare and Co Wicklow and the first case in a wild hare has been confirmed in Co Wexford.
RHD and RHD2 pose no risk to humans.
Why has the licence to capture hares been temporarily suspended?
This is the first time that RHD2 has been found in the population of +233,000 wild hares in Ireland.
The disease is highly contagious and there is no cure for it. It can be spread directly between animals and in the faeces and urine of infected animals, as well as by insects and on human clothing. In addition the incubation period may last several days and apparently uninfected animals may in fact be carriers.
The implications for the conservation status of the Irish hare, an endemic species, are potentially catastrophic, given the mortality rates seen in other lagomorphs elsewhere in Europe.
Hares are mainly solitary, except for during late winter and spring they can be seen in pairs or small courtship groups. So, netting and keeping large numbers in enclosures would greatly increase the likelihood of the virus spreading.
If one infected animal is found in netting for a coursing meeting then the entire capture would need to be put down.
Under these circumstances the catching of hares in nets, their transportation in boxes and the collection and holding of hares in confined areas can all be considered to increase the risk of disease spread.
What are the details of the tests carried out so far?
The first hare that was tested came from Wexford. Before death, the hare showing nervous signs, followed by sudden death. Tissue from the hare was tested by the Dept of Agriculture’s Kilkenny Regional Veterinary Laboratory in late July.
Nucleic acids were extracted from samples of spleen and liver using a Roche MagnaPure MP96 automated system in DAFM Virology Division, Backweston. Both samples were screened for variants of the Rabbit Haemorrhagic Disease Virus (RHDV) using PCR methods (Gall et al. 2007) to test for RHDV1 and (Duarte et al. 2015) to test for RHDV2. Both spleen and liver samples were found to be RHDV2 positive with indications of very high virus loads in both tissues (CTs =15 and =13 respectively).
These tests are conducted by the DA lab – the best in the country.
Can the wild hare and rabbit population not be vaccinated?
The existing vaccines for RHD and RHD2 are only proven to be effective on domestic rabbits and are untested on wild rabbits and hares. Given this, the risks would be too high to net and then vaccinate wild hares or rabbits.
When is the suspension likely to be lifted?
The suspension will stay in place until the National Parks and Wildlife Service and Dept of Agriculture have a clearer understanding of the extent, spread and implications of the RHD virus. The decision will be reviewed on an ongoing basis.
17 confirmed cases in eight weeks is significant by any measure and precaution is advised to prevent significant damage to the Irish hare population.
What has the experience been internationally?
RHD2 has been seen in wild rabbits in the UK for a few years. The brown hare has also been hit with RHD2 in the UK. Mortality rates have differed between areas, but in some areas up to 70% of the brown hares have been wiped out. There are significant concerns now about the potential for local extinctions of this species from parts of England. The disease has also been reported from mountain hares in Scotland, but there are no details yet about how widespread it is. There are no reports yet of RHD2 in Northern Ireland, but our counterpart in NIEA admitted they had not been looking for it.
There is no coursing of hares in the UK so there is no direct comparison there in terms of that issue. They do shoot hares extensively however (something we don’t do in Ireland, even though the open season would allow it). Prof Diana Bell in the University of East Anglia is leading the research on RHD2 in the UK. She is disappointed at how slow the UK authorities had been to try and contain outbreaks of the disease. She told NPWS that although the UK authorities had not banned hare shooting some shooting estates had voluntarily closed their estates to hare shooting in an effort to minimise disease spread and minimise the negative impacts on hare numbers.
Can the public do anything?
The public, particularly landowners, farmers, vets and the hare coursing community, is being asked to be on high alert and report any suspected sightings of diseased rabbits and hares as soon as possible to help efforts to monitor and control the disease. The NPWS can be contacted on firstname.lastname@example.org or 1890 383 000.
Other outdoor pursuits such as shooting or fishing are unaffected by the suspension of licences for netting hares. Hares are protected species and the Open Season review will take cognisance of that position.