SMALL MAMMAL HEALTH SERIES By Susan Brown, DVM

Gastrointestinal in this article refers to the entire digestive tract of an animal from the mouth to the anus. GI is the abbreviation for this word. The ferret can be affected by a variety of GI diseases but fortunately the majority of them are not life threatening.

Before we start the discussion of GI diseases of the ferret, we would like to remind you that the most helpful thing you can do as a pet owner is to be very observant of any changes in your pet's behavior. If necessary, write down patterns of change, length of time that abnormalities were noted, exposure to other animals, new foods or any other environmental factors. This is critically important information for your veterinarian should your pet become ill. Your pet's history can help your veterinarian determine what diagnostic tests and treatments may be needed. If your ferret is vomiting or having abnormal stools, it is helpful to bring in a sample of this material. You can place it in a zip lock bag and keep it cool until the time of your pet's examination. Most samples will keep up to six hours if kept cool and tightly sealed.

Remember that diarrhea and/or vomiting in an animal as small as a ferret can have devastating consequences if it is not attended to right away. Obtain veterinary attention for your pet as soon as possible.

GI FOREIGN BODIES

This is the most common cause of GI disease in the ferret under one year of age. Young ferrets love to eat latex or foam rubber of any kind and these materials can become lodged in the intestinal tract or sit for weeks to months in the stomach. In addition, older ferrets can develop hairballs in the stomach. There is some speculation that a chronic infection with Helicobacter mustelae may slow the stomach motility and may predispose a ferret to the formation of hairballs, but this has yet to be proven. Signs of a foreign body in the stomach can be subtle and can include any combination of the following: erratic appetite, wasting, occasional vomiting (although vomiting is uncommon), tarry stools, tooth grinding, lethargy and unusual aggressive behavior. The change to aggressive behavior may be caused by abdominal pain. If the foreign material slips into the intestine and becomes lodged there, than the signs are more dramatic and the situation becomes a true emergency. Signs in a ferret with a complete GI obstruction include any of the following: sudden collapse, uncontrollable vomiting, an absence of stools, severe dehydration, dark or bluish colored gums, bloated and painful abdomen, seizures and finally coma and death. The diagnosis of a foreign body is usually made on a physical examination of a fasted ferret along with an abdominal x-ray. Additionally a barium study or an ultrasound may be needed. The treatment is surgical removal of the foreign material.

INFECTIOUS DISEASE

VIRAL

• Rotavirus - This is a viral disease that can spread rapidly through a group of ferrets. The disease is usually very mild causing in soft, green, mucous-coated stools for two to three days. The diagnosis is made on signs and possibly by viral isolation from the stool. Treatment is rarely necessary because ferrets recover rapidly on their own. If necessary, supplemental fluids and intestinal coating agents may be used.
   
• Epizootic Catarrhal Enteritis (ECE) – This is the name given to “green slime disease” that has affected ferrets, particularly in shelters, since 1993. The current view is that this is a disease caused by a coronavirus. Fortunately, most ferrets recover uneventfully from ECE, however some, particularly older ferrets or those with other disease, can be severely affected. ECE spreads rapidly and ferrets exposed will exhibit signs of disease within 48 to 72 hours. ECE can result in both inflammation of the GI tract as well as inflammation of the liver. The liver enzymes may be elevated on blood tests. It is unknown if the GI inflammation and the liver inflammation are two different forms of the same disease, or if there are other factors causing the differences.

  The signs of illness initially can range from vomiting and a soft, green, mucous-coated stool to bloody diarrhea. Some ferrets are unaffected and can be carriers of the virus. Recovered ferrets may also be carriers. Young ferrets usually recover from ECE rapidly, but older ferrets may lose significant body condition and continue wasting once the diarrhea is gone. The diagnosis is based on the clinical signs, the history of exposure, serum biochemistries and a rule-out of other disease. Treatment depends on the severity of the illness and can include intestinal coating agents or antacids, antidiarrheal drugs, antibiotics, injectable fluids and dietary changes. Remember that antibiotics will not affect viruses, but may be used if a secondary bacterial infection is suspected.
   

• Influenza - Ferrets are susceptible to human influenza and primarily develop upper respiratory signs. Occasionally a ferret can also exhibit diarrhea. The diagnosis is based on the history and signs of upper respiratory disease along with diarrhea. Treatment ranges from none to fluid replacement, antihistamines for the upper respiratory signs and antidiarrheals. Most ferrets recover from influenza on their own in a week or two with very little supportive care.

BACTERIAL

• Helicobacter mustelae - This is a common bacterium found in the stomach of many ferrets where it may reside without causing any disease. It is not know what other factors are needed in order for this bacteria go from “neutral” to “unfriendly”. Helicobacter mustelae can cause disease ranging from a mild irritation of the stomach lining to multiple stomach ulcers. Ferrets can exhibit any of the following signs when affected by Helicobacter mustelae gastritis; lymph node enlargement (particularly the ones near the stomach), lethargy, painful abdomen, tooth grinding, excessive salivation, vomiting, loss of appetite, wasting and soft black stools. Tooth grinding and excess salivation may be the result of a feeling of nausea. The diagnosis is made from a combination of the following: the signs, a complete blood cell count, response to therapy and a stomach biopsy. The treatment for Helicobacter mustelae is based on combination antibiotic therapy. A combination of amoxicillin, metronidazole and antacids is the classic treatment. Other experimental treatments have been tried including the use of corticosteroids to suppress severe inflammation. The treatment will likely never completely rid the ferret of the bacteria, but can control the signs so the ferret is more comfortable.
   
• Other Bacterial Disease - Ferrets are relatively resistant to other GI bacterial diseases. Salmonella is very rare in the ferret. Proliferative bowel disease, which is caused by a campylobacter-like organisms, was much more common in years past but is relatively rare now. It is primarily a disease of ferrets under one year of age. The diagnosis of bacterial enteritis of ferrets is made on the signs, culture of the intestinal contents and/or intestinal biopsy. The treatment is a combination of antibiotics and other supportive care.

PARASITES

GI parasites are rare in the American ferret largely because the majority of ferrets are raised in large parasite-free breeding colonies. However, parasitic problems do occasionally occur where ferrets have access to contaminated food or water or the stools of animals containing parasites. The two most common parasites encountered in the American pet ferret are coccidia and giardia, which are both one-celled protozoal organisms. The signs of disease can range from none to diarrhea and wasting. The diagnosis is made on a direct microscopic examination of very fresh feces or on special stains that can be performed on the feces. Treatment involves the use of antiparasitic drugs for a minimum period of two weeks along with environmental cleanup to remove contaminated feces. Ferrets can also be infested other parasites such as tapeworms, roundworms and hookworms. These parasites can be transmitted from other pets in the household. If you have other pets in the household diagnosed with a parasite problem then you should have your ferret's stool checked for parasites as well.

NEOPLASIA (CANCER)

• Lymphoma is a common neoplasia that can cause in GI disease in the ferret. This is a cancer of lymph tissue and can affect many areas of the body. The intestinal tract is rich in lymphatic tissue so it can be a target for lymphoma and ferrets of any age can be affected. The signs are variable and can include any of the following: lethargy, prolapsed rectum, chronic diarrhea and wasting. The diagnosis of lymphoma is based on the signs, a complete blood cell count which often shows a higher than normal lymphocyte count, and a biopsy of affected intestinal tissue. The treatment for lymphoma is chemotherapy, but unfortunately, this treatment is often unsuccessful with the intestinal form. Corticosteroids can offer some relief for a period of time but are not curative.
   
• Adenocarcinoma – Adenocarcinoma can affect any glandular area of the body. We have seen this cancer in the pylorus (the outflow area) of the stomach and in the area of the anal glands. Cancer of the pylorus constricts the area and restricts the outflow of food from the stomach. The signs seen are the same as for a GI foreign body. The diagnosis is based on an exploratory surgery and biopsy of the affected tissue. This cancer responds poorly to chemotherapy. Adenocarcinoma of the anal gland can occur with the whole gland is present or when just a portion is left after anal gland removal. It causes a large swelling next to the anus and may cause compression of the stools as they pass through the rectum. The treatment is by surgical removal of the tumor.

  In addition to these cancers we have seen one case of primary stomach cancer and many cases of cancer in the liver which was either primary or had spread from other areas. Disruption of liver function can also lead to GI signs including diarrhea, wasting and vomiting. The diagnosis is based on a liver biopsy.

OTHER GI DISEASE

• Eosinophilic Gastroenteritis – This is a GI disease of ferrets that causes severe inflammation of the intestinal tract possibly in response to an allergen. The body sends eosinophils , a type of white blood cell often seen in allergic reactions, to the intestine. Here the eosinophils release histamine, which is a very irritating substance. The resulting irritation to the intestinal lining causes severe diarrhea and the inability to absorb nutrients. The ferret will start losing weight and will eventually waste away. Some ferrets become so severely affected that they also develop swollen ears and feet and ulcerations on the skin. The diagnosis is based on a complete blood cell count that usually shows a high number of eosinophils and a biopsy of the intestine and surrounding lymph nodes. Classically this disease has been treated with corticosteroids to reduce the inflammatory reaction and the response to the histamine release. This will, indeed, control the signs of the disease, but often has to be given for the life of the pet. We have found that making dietary changes causes a significant reduction in the signs leading us to speculate that eosinophilic gastroenteritis may be a food allergy problem. Some ferrets no longer need corticosteroids when changed to a “hypoallergenic” diet. We recommend feeding a diet completely devoid of grains. Wysong's Archetype freeze-dried diet is a good choice. Please read the handout Rethinking the Ferret Diet for more information.
   
• Toxins - Ferrets love to get into mischief and can investigate all kinds of things around the house including purses or trouser pockets! Ferrets have been known to eat aspirin, rat poison, toxic plants and antifreeze among other things. Signs can range from mild diarrhea and vomiting to complete collapse and coma. The diagnosis is based on the history of exposure to toxins and on blood tests and response to therapy.
   
• Dental Disease –Ferrets generally have minor dental problems such as tartar buildup, periodontal disease or fractured teeth. Occasionally a ferret will develop an abscess in a tooth root or cancer of the gums. Ferrets with dental disease may exhibit pain and refuse to eat hard food items or drop food from their mouth when attempting to eat. They may squint their eyes or have excessive tear production. The gums can be reddened or thickened and there may be an odor to the mouth. The diagnosis of dental disease is by visual and x-ray examination. The treatment is based on the problem and may include dental cleaning, surgery and medications.
   
• Rectal Prolapse – In rectal prolapse, the rectal tissue protrudes from the anus. This is most often a disease of the young ferret that has had an anal gland removal. In these cases the nerves or muscles around the anus may have been disturbed during the surgical removal of the anal gland. This leads to a relaxed anal sphincter muscle, which allows the rectal tissue to protrude. Other causes of rectal prolapse are any condition that causes the ferret to strain when he/she defecates thus pushing out rectal tissue including intestinal lymphoma, proliferative colitis, severe parasitism, intestinal intussception (where the intestine telescopes on itself), and GI foreign body.
   
• Megaesophagus – This is a rare disease of young ferrets where the esophagus is dilated and lacks the proper muscle tone to move through it properly. The signs of this disease include regurgitation of undigested food, wasting and sometimes aspiration of food into the lungs. The diagnosis is based on a barium swallow and x-ray showing the enlarged esophagus. There is no cure for this disease and treatment is based on feeding small, frequent meals to facilitate the movement of food through the diseased esophagus.
   
• Other Systemic Disease – Both liver and kidney disease can cause clinical signs that might be misinterpreted as evidence of GI disease. Diarrhea, vomiting, mouth ulcers, wasting, lethargy and loss of appetite are among a few of the signs caused by liver and kidney disease. The way to differentiate primary kidney or liver disease from primary GI disease is through physical examination, serum biochemistries, complete blood cell counts, urinalysis, x-rays and ultrasound. The treatment depends on the diagnosis.

revised 3/13/01

Date Published: 3/13/2001