Our Hares are Dying
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| In many parts of the Midlands hares have colonised Bord Na Móna cutaway boglands where formerly there was little wldlife but now there is concern that the population is under threat from diseases formerly associated with rabbits - Myxomatosis and Rabbit haemorrhagic Disease |
I
received a phone call recently from an old acquaintance in the live hare
hunting community. These are people who
hunt wild hares with Beagles and as such are the most eco-friendly of the
hunting groups as they don’t kill the hare - a healthy hare can easily outrun
the stubby-legged Beagle. They are also
the most in-touch group as surely they must be since their sport takes them on
foot across miles of countryside where they have opportunity to see wildlife
most of us never see. My acquaintance
was particularly worried by a sudden decline in the hare population in county
Monaghan. Hares have, as a species,
faced many challenges over the years but in recent years have showed an
increase in numbers so a sudden decline was particularly worrying. Anecdotal evidence suggested that disease was
the cause and in particular, Myxomatosis.
Other sources in Britain have suggested that Rabbit Haemorrhagic Disease
may be responsible. Now if there is a
single topic within the context of wildlife and hunting that is replete with
mythology, uninformed guesswork and downright lies it is Myxomatosis and for
this reason I immediately reached for the definitive work on the subject by
Michael J. Conry; “The Rabbit Industry in Ireland”. I have reviewed this book elsewhere in this
blog and I expected to find useful facts within its covers.
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| Michael J Conry is the Ireland's's foremost expert on all matters rabbit |
I quote: ‘The
highly infectious viral disease, Myxomatosis, caused by the Myxoma Virus in a
South American rabbit was introduced into wild rabbits in Australia (1950),
France (1952), Britain (1953), and Ireland (1954). It had an immediate and
catastrophic effect on rabbit populations.’
‘The
most important mechanism of transmitting the disease, however, is by anthropod
invectors (carriers) and a wide variety of winged carriers have been
identified. In Australia, early field
investigations demonstrated the importance of mosquitoes as vectors. Fenner and Ross likened the role of the mosquito
to a flying pin. Thus, any Anthropod (flea or mosquito) that
“probes or bites a lesion on an infected rabbit and then bites a susceptible
rabbit is a potential carrier’. ‘Fenner
and Ross concluded that compared with fleas, mosquitoes were of minor
importance in the transmission of Myxomatosis in wild rabbits in Britain”.
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| European rabbits (Oryctolagus cuniculus) were introduced to Australia in the 18th century with the First Fleet and eventually became widespread. Such wild rabbit populations are a serious mammalian pest and invasive species in Australia causing millions of dollars of damage to crops. Their spread was enhanced probably through the emergence of strong crossbreeds and eventually led to the introduction of Myxomatosis |
Several
people were responsible for the introduction of Myxomatosis to Ireland. They were Paddy O’Keeffe, editor of the Irish
Farmer’s Journal and John Mooney, John Monahan and Myles Smith who were members
of the National Farmers’ Association. Their
motivation was the destruction of agricultural crops attributed to rabbits
which widespread trapping had failed to prevent. A Dr. MacCooper of Wye College in Kent was
contacted who provided a sample of a dead rabbit killed by Myxomatosis. John Monahan’s farm at Castletown Castle
outside Carlow town became the epicentre for the spread of Myxomatosis in
Ireland. Farmers from all over Ireland
went to Castletown to collect diseased rabbits.
By the end of 1954 Myxomatosis had spread to every county in Ireland and
the rabbit population crashed and with it the rabbit export industry that had
existed for decades.
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| This rabbit was suffering from Myxomatosis and has been shot in the head with a .22 subsonic bullet but the distinctive swelling can be seen around the eyes |
In
rabbits of the genus Sylvilagus (cottontail rabbits) living in the Americas,
myxomatosis causes only localised skin tumours, but the European rabbit
(Oryctolagus cuniculus) is more severely affected. At first, normally the disease is visible by
lumps (myxomata) and puffiness around the head and genitals. It may progress to
acute conjunctivitis and possibly blindness; however, this also may be the
first visible symptom of the disease. The rabbits become listless, lose
appetite, and develop a fever. Secondary bacterial infections occur in most
cases, which cause pneumonia and purulent inflammation of the lungs. In cases
where the rabbit has little or no resistance, death may take place rapidly,
often in as little as 48 hours; most cases result in death within 14 days. Often the symptoms like blindness make the
infected rabbit more vulnerable to predators.
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| Myxomatosis and RHD are not the only diseases affecting rabbits and hares. This young rabbit had a heavily parasitised liver |
Of
RHD Michael J Conry wrote: “Viral
Haemorrhagic Disease was first described in domestic rabbits in China. The rabbits died of haemorrhages of the
respiratory and digestive systems, spleen and cardiac muscles. A few years later the disease appeared in
Spain and France in the late 1980’s, under a series of different names, causing
high mortality rates in domestic and wild rabbits AND IN HARES”.
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| Freshly killed rabbit cooked over a campfire made many a memorable day's hunting but one might think twice about eating rabbit today |
On
the 11th of October 2018 the BBC reported:
The
mysterious deaths of hares have sparked concern about the future of the species
in the East of England. Suffolk and
Norfolk Wildlife Trusts are working with the University of East Anglia (UEA) to
look into a recent batch of deaths. Dr
Diana Bell said myxomatosis and haemorrhagic diseases were possible causes and
is asking people to report sightings of the dead animals. She said losing a large number of hares would
be "disastrous" for the region.
The People's Trust for Endangered Species estimates there are around
817,500 left in the UK. Suffolk Wildlife
Trust said the number nationally had declined by 80% over the past 100 years,
with the animals hunted year-round and also facing threat from illegal hare
coursing. Over the past month,
landowners and farmers have reported several sightings of sick or dead hares -
many of which were around Bungay. In one
case, six hares were found dead in a field.
Dr Bell has asked people to get in touch if they find a dead hare in
"unusual circumstances".
"We need to know what is happening," she said. "East
Anglia is a really important stronghold for brown hares so it would be
disastrous if we lost them. "Hares
are really up against it so getting good images of the bodies, along with their
exact location, is crucial for us to rule out or identify possible
diseases. "Until we get more cases,
we can't call it." Dr Bell said
that hares, which are larger than rabbits and have longer hind legs, were at
risk from RHD2, a haemorrhagic disease that "got into the wild big-time in
the last three years". But she also
said myxomatosis had been "particularly virulent" in rabbits this
autumn and it was possible the highly-contagious disease could "make the
jump to hares". "Myxomatosis
in hares is rare but earlier this year there was a huge die-off in Spain,"
she said. "That was the first time it had happened. "We're losing both our rabbits and our
hares but if we lose our hares, we're going to be in trouble."
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| RHD was first noticed by ferreters who began digging emaciated and dying rabbits out of warrens. These fine plump specimens are obviously healthy |
RHD
(Rabbit Haemorrhagic Disease) primarily infects only adult rabbits. In fact,
research has shown that rabbits younger than 8 weeks of age are resistant to
the virus. The incubation period for the RHD virus is between 1 and 3 days,
with death following 1 to 2 days after the infection. There is a wide range of
RHD symptoms. Most rabbits will show no signs of external symptoms of RHD. Symptomatic cases of RHD will display fever,
squeals, and often coma leading to death within 12 to 36 hours. In less severe
cases, rabbits may display uneasiness, excitement, anorexia, swollen eyelids,
paralysis, ocular haemorrhages, and "paddling" or loss of skin.
Convulsions may be seen as well. A fatal bloody discharge from the nose has
been exhibited along with blood-stained cage floors, though these symptoms may
have occurred after death. Rabbits who have recovered from the less severe
symptoms usually develop severe jaundice with weight loss and lethargy.
Diarrhoea, constipation and abdominal cramping are then exhibited right before
death a few weeks later. RHD causes
rapid development of blood clot formation in major organs such as the heart,
lungs and kidneys. The clots block blood vessels causing heart and respiratory
failure. An infected rabbit that has died from RHD will often have its legs
straight out and head over its neck
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| This pair of hares lived in the fields at the back of my home. I haven't seen them or their descendants for years |
The
survival prospects for the Irish rabbit population are not good, it seems, and
now even the hare population may be threatened by a new strain of Rabbit
haemorrhagic disease, RHDV2. Rabbit
haemorrhagic disease first appeared in the Winter of 1983 in Jiangsu Province
of the People's Republic of China.
Fourteen million domesticated rabbits died within nine months in the
outbreak. In 1984 the virus that caused
the disease was identified. The virus spread westward and reached Europe in
1988. By the late 1990s, RHD stretched
to forty countries and had become endemic in wild and feral rabbit populations
in Europe, Australia, New Zealand and Cuba.
In Europe, there was a rapid increase in research into RHD, due to the
importance of the commercial breeding of rabbits for meat and fur
production. In Ireland RHD has been
present for about ten years and together with Myxoma virus and various
parasitic diseases has eliminated rabbits over large areas of the
countryside. There is evidence of its
spread by scavengers. In 2010, a new
virus variant called rabbit hemorrhagic disease virus 2 (RHDV2) emerged in
France. In April 2016, a highly lethal
disease started affecting one of the northernmost feral rabbit populations in
the world in Helsinki, Finland. The
outbreak has since been identified to be caused by either strain of RHD, being
the first appearance of the virus in that country. Recently, in Sicily, veterinary scientists
reported a case of RHDv2 which jumped species and infected a hare. There are several variants of the virus that
causes Rabbit (or Viral) Haemorrhagic Disease (RHD or VHD). Some variants do not cause disease but
stimulate immunity. The virus that
causes RHD is a calicivirus. Calicivirus
readily mutates and causes sudden death and has a high mortality rate (up to
90%) in unvaccinated rabbits. Young rabbits (<4weeks) have natural immunity
that wears off over 4-6 weeks. The
RHDV2 is less virulent than the original strain. It has a lower and variable mortality rate
(5-70% with an average of 20%). It can also affect rabbits under 4 weeks
old. Although rabbits can die suddenly,
some can recover and others may show no clinical signs at all. The virus that causes RHD is very difficult
to kill. It can survive outside the body
and is resistant to temperature changes.
It can survive at 50 degrees centigrade for an hour i.e. some washing
machine cycles. RHD and its variants are
easily spread. The virus can survive in
the digestive tract of animals that feed on carcasses of rabbits that have
died. For example, faeces from crows,
foxes and flying insects can infect rabbits.
In the UK, definitive diagnosis of RHD is difficult in the live animal. There is no blood test. Diagnosis is usually made after death. Post-mortem signs may or may not show
definite signs. Microscopic examination of the liver and other organs will show
signs that are highly suggestive.
Vaccines are only partly effective.
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| The Irish Hare is a magnificent creature and much mentioned in our mythology. It's loss would be a tragedy |
So
the news on disease among rabbits and hares is bleak. Both species are infected by two of the most
virulent diseases to appear among these species in the last seventy years. In a recent report on October 16th
2018 the Irish Times reported:
“Recent
reports of myxomatosis in brown hares in the UK is of interest, and Department
of Agriculture, Food and Marine regional veterinary laboratories have been made
aware of this finding. There have been no reports of myxomatosis-like syndromes
in Irish hares, nor have there been any confirmed cases. On present knowledge and information, the
reports from the UK, by themselves, provide no basis for any concern that the
detection of a disease in a different species in the UK is any specific threat
to Irish hares”
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| The Belgian Hare is really a big domestic rabbit and this Co. Tyrone breeder is worried about disease |
So
it would seem the Irish authorities are unaware of the problem and deny it
exists in Ireland when reports from the field indicate otherwise. One suspects a certain reluctance among
officialdom to accept the evidence of hunters who are generally considered to
be part of the problem of decline in wildlife populations. This is unfortunate since there are far more
untrained but nevertheless very observant wildlife watchers in the hunting
community than there are highly paid civil servants doing official population
surveys.
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| Old rabbit hunters don't die; they go target shooting - something the antis don't like to give them credit for |
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| Buzzards have been observed preying on rabbits and young hares and many are asking whether this introduced species is threatening the survival of both |
