Fw: [Meatrabbits] Re: myxomatosis
----- Original Message -----
From: catsandlops <hlhrabbitry@...>
Sent: Tuesday, July 29, 2003 8:04 PM
Subject: [Meatrabbits] Re: myxomatosis
The OLRCB message board had these things posted. The Albany open
show on Sunday was even cancelled because of this outbreak. I
haven't verified the accuracy of any of the following.
There are two forms of the disease, an acute or rapid killing form,
and a long-term, chronic form. In the first form, breeders often
don't see a problem until the rabbit dies. You may see a slight
redness of the eye a day or two prior to death. You may also notice
that the rabbit does not eat well. In the long-term form of the
disease the eyelids, lips, face and sometimes ears swell up to
gigantic proportions. Another sign which will almost always confirm
Myxomatosis is the swelling for the vent area in does and the scrotum
in bucks. The rectal temperature will be 105 - 106.
There is no known treatment for Myxomatosis. The only method of
combating the disease is to immediately destroy affected rabbits. If
a rabbit goes off feed, take it's rectal temperature. If the
temperature is above 103.5, kill the rabbit and burn or bury the
carcass. Because the disease is so deadly, it is better to make a
mistake and kill a rabbit that doesn't have Myxomatosis than to allow
one to live that does have it. Keeping flying insects out of the
rabbitry is helpful in preventing the disease; however, the disease
can also be transmitted by direct contact and by your hands. People
living in Oregon and California should be very careful about sending
rabbits to shows and fairs in the late summer and fall. Any sick
rabbit should be immediately removed in order to protect the others
at the show.
this is the latest from the state vet's office:
7-30-03 RABBIT DISEASE OUTBREAK A CONCERN, MAY SPREAD
By David Stauth, 541-737-0787
SOURCE: Dr. Donald Mattson, 541-737-6877
Dr. Beth Valentine, 541-737-5061 Dr. Brad Leamaster, 503-986-4680
CORVALLIS - The private and commercial rabbit growers of Western
Oregon may be facing this summer one of the periodic epidemics of
myxomatosis, a disease with an extremely high mortality rate that
shows up somewhat unpredictably in the European rabbits most commonly
reared in Oregon.
A sudden outbreak of the disease in Linn and Benton counties in early
July prompted the closure of rabbit shows at the county fairs in
those two areas. But whatever combination of viral, population or
climatic conditions caused these cases may also lead to more
widespread outbreaks, according to experts in the College of
Veterinary Medicine at Oregon State University.
Myxomatosis, which last caused major problems in the state more than
a decade ago, is extremely infectious, is transmitted naturally by
mosquitoes or other insects, can be spread from rabbit to rabbit by
human handlers and has no cure. There is no diagnostic test in live
animals and no available vaccine.
"The last time we had a major outbreak in the 1980s this caused a
horrible problem in the Willamette Valley and Southern Oregon," said
Dr. Donald Mattson, an associate professor of veterinary medicine at
OSU. "It can have a mortality rate higher than 90 percent in European
There are a few primary precautions that rabbit owners can take to
protect their animals, Mattson said. The most important would be
mosquito netting, which may help protect against mosquito and other
insect transmission. But animal handlers should be careful about use
of such netting in very hot weather, since it may impair air flow in
rabbit hutches. Beyond that, the best prevention is avoiding groups
of other rabbits which may be infected, such as at rabbit shows or
"For rabbits, this is a very deadly disease," said Dr. Beth
Valentine, an associate professor of veterinary medicine at
OSU. "From the point of view of a rabbit owner, the best place for
these animals is behind mosquito netting, at home, until the worst of
the mosquito season passes later this fall. People who own rabbits in
Western Oregon should be very cautious until this problem has
Myxomatosis is a poxvirus that has a natural reservoir in nature,
perhaps among brush rabbits, the OSU experts say. It is far less
deadly to wild rabbits, although they too can be affected. Exactly
what triggers the periodic outbreaks among domesticated rabbits is
less clear. It may be some combination of immunity levels in wild
populations, heat stress, other weather conditions, mosquito
populations and other factors.
The disease is also not easily diagnosed, and often it's misdiagnosed
by veterinary doctors who see it infrequently. Symptoms can include
high fever, loss of appetite, swelling of mucus membranes or
sluggishness. The underlying cause of mortality is a profound
suppression of the animal's immune system, making them vulnerable to
a host of other health problems. Nodules called "myxomas" may appear
in some cases. But at times an animal has appeared fairly healthy and
been dead the next day.
There is no treatment other than supportive care for secondary
infections, veterinary doctors say, and no vaccine is readily
available. Experts are now getting information on vaccines that have
been used with some success outside the U.S., but in any case it
would probably be too late for a vaccine to provide any protection
this summer, OSU doctors said.
Some of the facts known about myxomatosis include:
first was described in Uruguay in 1989, and spread northward from
there into Mexico and California, where it has evolved into
the "California" strain of virus, which often has high mortality but
fewer overt symptoms than some other strains.
All domesticated rabbits in the U.S. are highly susceptible to the
virus, but humans are not.
Mosquitoes, fleas, mites and biting flies may all help transmit the
virus, and it may also be carried in the air for unknown distances.
In rabbit colonies, mechanical transmission of the virus is often
observed, often by human caretakers or even the judge at a rabbit
If a rabbit is exposed to an infected rabbit, it should be
quarantined for 14 days and assumed to be infected during that
It's unknown exactly how severe this year's epidemic may become and
how far it will spread, the OSU experts say, although history
suggests it may not move much beyond Western Oregon.
In the interests of monitoring the spread of the disease, anyone who
owns a rabbit that dies from an unknown cause should consider
contacting their local veterinarian or arranging for an autopsy by
the Veterinary Diagnostic Laboratory at OSU, by calling (541) 737-
3261. There will be a fee for the autopsy. It's probable that the
disease has already caused many more deaths than have so far been
confirmed because it cannot be specifically diagnosed in live animals
and few people arrange for autopsies.
Dr. Brad Leamaster, the state veterinarian, is collaborating with the
OSU veterinary experts on the monitoring and management of this
"We'll try to monitor the spread of this disease as carefully as we
can and keep fair officials and the public advised of any
developments," Lemaster said. "At this point we're allowing officials
in local areas to make decisions about closing down such things as
rabbit shows at county fairs."
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Just a small correction: myxo was described in Uraguay in the late 1800s,
not 1900s as stated in the article.
P.S. I lost 4 rabbits last December. State necropsy confirmed it was myxo.
There was another case in the North Bay in March. Perhaps much of the
Pacific coast is in for another myxo outbreak.
- On Wed, 30 Jul 2003 07:22:35 -0800, Kathybill Spaldingbrungardt wrote:
>P.S. I lost 4 rabbits last December. State necropsy confirmed it was myxo.One of our California volunteers reports:
>There was another case in the North Bay in March. Perhaps much of the
>Pacific coast is in for another myxo outbreak.
>>Sadly, we have had an outbreak here in San Diego too. :(5 rabbits in the Chula Vista area and 1 in Oceanside/North County.
This post about the Oregon outbreak talks about transmission by handler and through the air... I just spoke to one of
our vets and he confirmed what I thought, that this is not typically the case. Has anyone else ever heard Myxo is
transmittable by handler or through the air? <<
Let me add that not all fevers are caused by Myxo, and euthanasia
shouldn't be recommended just because a rabbit spikes a fever.
I don't think that was the original intention, but rather just how
some might interpret it.
- One point to keep in mind...this is a suspected
outbreak, not a confirmed one. I've been following
the local rumor mill (and know the lady who sent it
to meatrabbits) and checking things out, and as far
as I know, there's nothing definite (like a sure necropsy)
It's also been hot enough here to have animals die from
Rumor mill stuff, though, apparently a rumor made it
onto Showbunny that an outbreak of myxomatosis happened
at Multnomah County...I was the superintendent of the 4-H
show, and I can firmly say that no such thing happened. We
were releasing animals early due to heat stress and other weirdnesses
(such as a drunk grabbing the Best of Show 4-H rabbit out of
the cage and walking around with it on Thursday night, Thursday
night seems to bring out all the crazies, the kid wanted to take her
rabbit home after that and I didn't blame her), but no actual disease.
I was being pretty generous about it because we were cooping the
rabbits under a tent on blacktop, and one person's thermometer was
registering in the 90s on top of the cages....
So let's not panic...yet, but get suspicious deaths necropsied so that
if there *is* an outbreak for sure, then the State Vet can take action.