Gastrointestinal Diseases in the Ferret (Part III)

Katrina D. Ramsell Ph.D, DVM

(June 2004)

In this article I would like to continue discussing some of the common gastrointestinal (GI) diseases of ferrets.  This article will address inflammatory bowel disease, bacterial overgrowth of the intestines, and GI cancer.

1. Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an inflammatory condition of the gastrointestinal tract that is quite common in ferrets. Although the cause of IBD is unknown, this chronic immune response may be associated with food allergies, dietary intolerance, bacterial overgrowth, starch overload, infectious disease, metabolic disease, or other factors.  There could potentially even be a genetic predisposition for the disease in ferrets.

IBD is usually seen in ferrets that are over a year of age and is observed most commonly in ferrets over two.  This disease is associated with inflammatory changes in  both the stomach and small intestine, resulting in gastritis and enteritis respectively.  Because the signs of IBD can resemble other common GI diseases, it can be fairly easily overlooked or misdiagnosed.  Accurate diagnosis and treatment of IBD can be critical in pet ferrets.  Chronic damage to the gut from IBD can potentially cause malnutrition and emaciation, secondary bacterial overgrowth and infection, hepatitis, and eventual development of lymphoma, which is a type of cancer.

IBD in ferrets is often diagnosed incidentally when they are presented for some other illness, such as adrenal disease or insulinomas, and have blood work done.  There are certain blood values that can be altered when a ferret has IBD, and this can make one suspicious that a ferret has the disease. Unfortunately, the only way to definitively diagnose IBD is to actually do biopsies of the stomach and intestine.

Many ferrets that have IBD do not display any clinical signs.  Signs are more       often observed when the disease becomes more advanced or when secondary disease occurs (such as bacterial overgrowth or liver disease).

Clinical signs of IBD include:

1. Abnormal stools (chronically greenish or mucoid stools, grainy or “birdseed” stools, tarry or bloody stools, episodes of watery diarrhea).  Stomach and intestinal ulcers can cause stools to be bloody or tarry (black stools represent digested blood), and seedy stools indicate food that has not been completely digested.

2. Nausea (pawing at mouth, grinding teeth, etc.) and/or vomiting.  This can be caused by ulcers or from inflammatory changes.

3. Thin body build, especially along the back and over the pelvic and shoulder areas due to reduced muscle mass (Note: prednisone and adrenal disease can also cause muscle wasting).  Muscle wasting can come from the reduced ability to properly process and digest food and to absorb nutrients.  It can also occur from losing protein from the intestines due to the gut being “leaky” from inflammation.

4. Decreased activity or lethargy may be observed as the disease progresses and the ferret’s overall condition declines.

5. Some older ferrets will more commonly have trichobezoars (hair balls) when IBD is present.  It is likely that this occurs as a result of decreased gastric motility secondary to the underlying gastric inflammation.

Bloodwork values associated with IBD:

1. Lipase and globulin values are often elevated in ferrets that have IBD.  Lipase is an enzyme released into the blood by the stomach (and by the pancreas when a ferret has pancreatitis, which is a rare occurrence).  When the globulinvalue is elevated, it indicates a significant inflammatory response, and the source of inflammation is almost always the gastrointestinal tract.

2. Liver values such as ALT and GGT may be elevated due to the gut inflammation spreading into the liver.  (Note: liver infections, adrenal disease, primary liver disease, and prednisone can also increase these values).

3. The complete blood count (CBC) may reveal an increase in certain types of white blood cells that may indicate IBD, lymphoma, or an underlying disease associated with IBD.

There is usually no cure for IBD, but the goal of therapy is to control inflammation and damage to the stomach and intestines, both to alleviate symptoms associated with the disease and to prevent transformation to lymphoma.  Use of a hypoallergenic or novel protein diet may reduce gut inflammation if a food allergy is the cause; low starch diets may help if starch overload and subsequent bacterial overgrowth is the cause.  However, dietary changes alone are rarely enough to control IBD.  A drug called azathioprine (Imuran®) is frequently used to control the inflammatory response in ferrets with IBD.  Sometimes other anti-inflammatory drugs, such as prednisolone or budesonide, may be used in conjunction with Imuran®.  Antibiotics such as Baytril® often reduce clinical signs such as diarrhea and nausea.  Other medications such as vitamin B12 and colostrum can potentially improve absorption of nutrients from the gut.  Often clinical signs, if present, will improve as the inflammation is controlled.  Although IBD can be controlled successfully with medication, some ferrets do not respond as well as others to treatment.  Research is ongoing for inflammatory bowel disease, as it is a disease that is seen in many species and is still not completely understood.

2. Bacterial Overgrowth

Bacterial overgrowth refers to an increase in the growth and aggressive behavior of otherwise normal intestinal bacteria.  It is usually secondary to some underlying disease or stressful condition, such as inflammatory bowel disease, coronavirus (ECE), GI foreign bodies, inappropriate diets or sudden dietary changes, and other generally debilitating conditions.  Prompt treatment of bacterial overgrowth is recommended, as this condition can potentially become quite serious relatively quickly. A thorough exam and appropriate diagnostics can also help determine the underlying cause for the bacterial overgrowth.

Signs observed with bacterial overgrowth typically include diarrhea (frequently greenish), decreased appetite, weight loss, decreased activity, nausea, and occasionally vomiting.  Sometimes dehydration occurs secondary to fluid loss (from diarrhea or vomiting) or from decreased fluid intake (from reduced drinking or reduced absorption from the gut).  Signs can be mild and sporadic, and episodes can be weeks or even months apart.  If repeated episodes are observed and the diet has been consistent, then there is likely an underlying disease present such as inflammatory bowel disease.

Treatment of bacterial overgrowth consists of broad spectrum antibiotics (often a combination is used such as Baytril® or Flagyl® and amoxicillin) and supportive care.  One may need to give supplemental feedings and/or fluids, and sometimes medications are needed to help control the diarrhea.  Although antibiotics may help with an immediate episode of bacterial overgrowth, treating the underlying disease or primary problem is always the preferable long-term treatment plan.

3. Gastrointestinal Neoplasia (cancer)

Lymphoma is the most common type of GI cancer in ferrets.  In many cases, it is likely due to unrecognized chronic inflammatory bowel disease that has progressed to cancer.  Other underlying diseases such as Helicobacter can less commonly also initiate changes that lead to lymphoma.

Signs of lymphoma are variable and often depend on how aggressive the cancer is (high vs. low grade) and the location and extent of organ involvement. Weight loss, decreased appetite, lethargy, abdominal masses, and abdominal distension are common findings.  Sometimes peripheral lymph nodes (eg. in the neck region, in the arm pits, and on the back side of the rear legs) are firm and enlarged, and involvement with the eye can cause the eye to be pushed out and appear to be deviated at an abnormal angle.  Some ferrets grind their teeth due to nausea and GI discomfort.  Intestinal lymphoma often results in tissue that is more delicate than normal and easily ruptured, and it is not uncommon for ferrets with GI lymphoma to have a rupture in the bowel wall and secondary peritonitis with subsequent death.

Unfortunately blood work does not provide a definitive diagnosis for lymphoma, although very high lymphocyte counts, especially in conjunction with elevated lipase and globulin values, can raise the index of suspicion for the presence of lymphoma.  If lymph nodes are firm and enlarged, whether they are abdominal or peripheral, biopsies should be performed to get a diagnosis as soon as possible.

Treatment of lymphoma, or any cancer in general, is often difficult.  Putting the cancer into remission for a period of time and improving and extending the quality of the ferret’s life are often more realistic goals than achieving complete resolution of the disease.  If a ferret is diagnosed with lymphoma, owners are encouraged to pursue treatment for their ferret.  Ferrets generally tolerate chemotherapy extremely well, and most ferrets do benefit to some extent from therapy.

There are different chemotherapeutic protocols for treatment of lymphoma.  Prednisone alone is an inexpensive, non-invasive treatment that can buy the ferret additional quality time.  A multi-drug protocol is usually more effective and often can provide the ferret with even more time compared to using prednisone alone.  Some multi-drug protocols involve giving chemotherapy drugs via oral suspensions as well as injections into the muscle and under the skin and by IV administration.  A new protocol that is becoming popular with ferret owners that have ferrets with lymphoma involves treatment with similar drugs but without any IV treatments.  This reduces the cost of treatment as well as eliminates the need to anesthetize the ferret for any of the treatments.  It is still too early to tell which multi-drug protocol is more effective in treating ferrets with lymphoma.