[Dr. Susan Erdman was kind enough to visit the June meeting of the GCFA
and she gave an excellent slide presentation on the work she and Dr. James Fox
are doing on ferret lymphomas at M.I.T.]
[long text follows]
Lymphoma is a very common cancer in ferrets, comprising about 20% of all
reported neoplasms. It is probably the most common tumor in young ferrets.
Lymphomas frequently occur in combination with pancreatic and adrenal tumors in
older ferrets, and it is probably more common than we realize. Occasionally
related or cohabitating ferrets will develop lymphoma which is also observed in
lymphomas in cats with Feline Leukemia Virus. Not surprisingly, viruses have
also been suspected of causing lymphoma in ferrets. Although no causal virus
has been identified, it is probably best to avoid introducing new ferrets into
cohabitating groups of ferrets which have many lymphomas.
Manifestations of malignant lymphoma vary with the age of the ferret. Young
ferrets usually become suddenly ill. Some owners report a ferret that seemed
normal one day and was discovered very weak the next day. Ferrets may have
difficulty breathing because of a large chest tumor. Some develop a very large
spleen that fills the abdomen. Others get very large lymph nodes around the
throat, armpits and knees. Tissue aspirates and biopsies are needed to confirm
lymphoma because sometimes a node that appears to be enlarged is actually a
fat pad in a ferret with a healthy appetite. Ferrets with internal involvement
may have diarrhea or difficulty urinating or defecating. Radiographs usually
reveal the characteristic soft tissue swellings of in the chest and abdomen.
Although a few young ferrets respond well to chemotherapy, the prognosis for
long term survival and well-being is poor, especially in ferrets which are less
that one year of age upon diagnosis. Getting an early diagnosis may increase
life expectancy slightly with much supportive care and chemotherapy. A young
ferret should be playful and have a good appetite, so if your ferret has a
change of appetite or attitude, contact your veterinarian for a thorough exam.
Older ferrets have more variable disease. Some develop sudden disease like that
of younger ferrets. Others have a prolonged illness that begins with periods of
weakness, poor appetite and weight loss that may go on for several years. The
earliest changes appear to occur in the spleen and blood, and may be detectable
by your veterinarian using palpation of an enlarged spleen or interpretation of
changes in the blood counts. A sample of the affected tissue is necessary to
confirm the disease. You veterinarian and pathologist can evaluate the tissue
cell distribution and cell division that help predict whether the tumor will be
rapidly progressive. Many of these older ferrets do very well for many years
following the diagnosis of lymphoma with minimal chemotherapy. Some drugs such
as steroids, which are used therapeutically for beta cell tumors of the
pancreas may provide some chemotherapeutic benefit for lymphoma as well. Older
ferrets should be examined regularly by a veterinarian, and any ferret
demonstrating recurrent poor appetite or lethargy should be examined more
frequently. Early diagnosis of disease gives a much better prognosis and allows
you to make informed decisions about the health management decisions of all of
your ferrets.
One final point: an enlarged spleen is common with lymphoma in ferrets, but has
been associated with many other conditions in ferrets as well. Even certain
anesthetics can cause a big spleen. Because ferret spleens can fluctuate in
size over days or weeks, an enlarged spleen should only be removed if it poses
an immediate threat to health such as splenic rupture, or confirmed splenic
lymphoma or other cancer. [IFNS]
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MARSHALL FARMS RESPONDS TO S.T.A.R. ARTICLE
-------------------------------------------
[Reprinted from the same issue (Vol.7 No. 6) of "Off the Paw"
The following statement was published in a recent issue of the S.T.A.R. Ferrets
newsletter...
"Marshall Farms ferrets have the problem [adrenal tumors] more often than any
other ferret, and it is a known fact that they inbreed as well as alter their
ferrets before 6 weeks."
Dr. Judi Bell, D.V.M., staff veterinarian for Marshall Farms, has the
following response...
We don't alter our ferrets before six weeks. They're usually at least
six weeks and often a little older. They're removed from the nest the week the
youngest ones turn 5 weeks, beginning on Monday with the ones that are already
more than 5 weeks old, and ending on Thursday with the youngest or smallest
ones. They stay in the shipping building for about 5 days before surgery is
done to them and the smallest ones are usually retained until the next week,
which means they are almost 7 weeks old when spayed. This is still pretty
young, but it's not 5 weeks. They're shipped about 5 days after surgery so the
youngest ones would be 6-1/2 weeks old at that time and the oldest might be 8
weeks old. We often have litters of 12 or 13 and those kits are the small ones
that take a while to catch up to the regular size litters.
I agree that it is probably detrimental in the long run to spay and
neuter ferrets at all, but, with the number of irresponsible and uneducated pet
owners around, it's usually safer for the ferrets.
It is also NOT a known fact that we inbreed. We avoid inbreeding as
much as we can. We have 10,000 breeders and it isn't that hard to avoid
breeding littermates and parent-offspring pairs. More of the females are
virgins than the males in any week, because, of course, we need to keep a lot
more jills than hobs. Therefore, the hobs are, on average, older than the
jills, and increasingly unlikely to be their littermates or even half-brothers
as the hob gets older. The fancy colors, particularly those with white on the
heads and those increasingly close to black-eyed whites, are sterile if you
breed the colors to each other anyway, so it wouldn't be too profitable to keep
trying to do it.
Some of the ferrets originally came from England, and there has been some of
polecat blood to enlarge the size over the years, so the gene pool is pretty
broad. It is true that we cannot identify the sold offspring of jills that we
have here and therefore we are unable to trace the ancestry of anybody's pet.
If we could do this we could probably eliminate lymphoma in a year or two. I
feel certain that it is caused by a virus, as similar diseases in cats, cattle
and poultry are, and this comes through the female side very strongly, being
spread probably in utero as well as in the colostrum of mammals. Until someone
identifies the virus, we can't test for the disease in our breeders , and until
we find an economically feasible way to identify both the breeders and their
kits at birth, we can't trace the parents of affected animals. We have a very
low incidence in our colony because of the relatively young age of the ferrets.
[IFNS]
[Posted in FML issue 0626]
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