The short version
Diseases that affect the stomach and intestines are common in dogs. They include infectious diseases such as bacterial, viral, and parasitic diseases and noninfectious disorders, such as tumors, bloat, and obstruction.
Canine Parvovirus
Canine parvovirus infection is a potentially fatal viral disease that most often affects puppies or unvaccinated adult dogs. The virus itself is resistant to a number of common disinfectants and may survive for several months or possibly years in contaminated areas. Rottweilers, American Pit Bull Terriers, Doberman Pinschers, English Springer Spaniels, and German Shepherds are at increased risk of disease, but any breed can be affected. With appropriate treatment, 68%–92% of affected dogs will survive the virus.
The virus is transmitted by direct contact with infected dogs or feces. Indirect transmission, such as from objects contaminated by feces, is also an important source of infection. The virus is present in the feces for up to 3 weeks after infection. Recovered dogs may serve as carriers.
After entering the body through the mouth or nose, the virus replicates and spreads to the bloodstream. It attacks rapidly dividing cells throughout the body, especially those in the bone marrow, blood cell-producing tissue, and the lining of the small intestine. Production of the virus in the intestinal lining causes severe damage and bloody diarrhea. Normal intestinal bacteria may enter the damaged tissue and the bloodstream, worsening the disease. Affected dogs can also have decreased numbers of white blood cells, which normally protect the body from infections. This allows for further damage by the virus and secondary bacterial infections. In young puppies infection may also rarely involve the heart, leading to signs of heart failure without digestive signs, such as diarrhea.
Treatment and Control
There is no specific treatment to eliminate the virus. Most dogs recover with appropriate supportive care, which is focused on replacing lost fluids and electrolytes. Oral electrolyte solutions (used to replace sodium and potassium that is lost through the intestines) may be used in mildly dehydrated dogs without a history of vomiting. More severely affected dogs will need intravenous fluids. Most dogs that survive the first 3 to 4 days of disease recover, usually within 1 week. Persistent vomiting can be controlled with prescription medication. Antibiotics may be added in cases where secondary bacterial infection is likely to be present.
Follow your veterinarian’s instructions for your pet’s diet. It was previously thought that food and water should be withheld until vomiting has subsided. However, it is now known that providing nutrition earlier on is associated with earlier improvement, weight gain, and improved gut function. Therefore, veterinarians may place a feeding tube in dogs that will not eat on their own. Once vomiting has stopped for 12–24 hours, frequent, small amounts of a bland diet (such as cottage cheese and rice or a prescription diet) can be slowly introduced. If signs recur after feeding, contact your veterinarian for directions. If food can be tolerated, the bland diet is usually continued for 1 or 2 weeks, after which the dog’s regular diet can be gradually reintroduced.
To limit environmental contamination and spread to other susceptible animals, dogs with confirmed or suspected parvovirus infection must be handled with strict isolation routines (separate housing, protective gowns and gloves for handlers, frequent and thorough cleaning of the area, etc). Contaminated areas should be thoroughly cleaned to remove visible dirt, feces, and other organic matter. Household bleach (diluted to 1 part bleach to 30 parts water) or commercial products labeled for use against parvovirus can inactivate the virus by being applied to the area after cleaning. The same solutions may be used as footbaths to disinfect household footwear. Disinfection of hands, clothing, and the dog’s food and water bowls and toys is recommended.
Inflammation of the Large Intestine (Colitis)
The large intestine (also called colon or large bowel) helps maintain fluid and electrolyte (salt) balance and absorb nutrients; it also temporarily stores feces and provides an environment for normal intestinal bacteria. When the colon is damaged by inflammation, parasites, or other causes, diarrhea is often the result.
Inflammation of the colon (called colitis) may be short- or longterm. In most cases, the cause is unknown; bacterial, parasitic, traumatic, kidney-related, and allergic causes are suspected. Inflammation may be the result of a defect in the function of the immune system in the colon. An exaggerated reaction to dietary or bacterial factors within the intestine, genetic predisposition, or results of previous infectious or parasitic disease have also been implicated.
Animals with inflammation of the colon may strain to defecate and may pass mucus-laden feces, sometimes containing blood. Feces are often of a small volume and a more liquid consistency, with increased frequency. Dogs often have accidents because of increased urgency. Affected dogs can also have pain when defecating. Weight loss and vomiting are rare and much less common than in dogs with diseases of the small intestine. Signs can come and go but tend to worsen with time.
How Can Fiber Help with Diarrhea?
Dietary fiber reduces free water in the feces, prolongs the length of time food is in the intestines (increasing the opportunity for the food to absorb water), absorbs poisons, increases fecal bulk, stretches the smooth muscle of the colon, and improves the ability of the intestines to contract.
Constipation
Constipation refers to difficult or infrequent elimination of stool, which is usually dry and hard. It is a common problem in dogs. In most instances, the problem is easily corrected; however, in sicker animals, the condition can be severe. The longer feces remain in the colon, the drier, harder, and more difficult to pass they become. Obstipation is constipation that resists treatment, in which the animal is unable to successfully defecate.
Signs of constipation include straining to defecate and the passage of firm, dry feces. If the passage of feces is hindered by an enlarged prostate or lymph nodes, the feces may be thin or ribbon-like in appearance. Passed feces are often foul-smelling. Some animals are quite ill and also have lethargy, depression, loss of appetite, vomiting, and abdominal discomfort. Your veterinarian can confirm the presence of retained fecal matter by feeling the abdomen and performing a rectal examination. Abdominal x-rays may help establish the cause of fecal retention and indicate whether the feces contain foreign matter, such as bones. Be sure to tell your veterinarian about any tendency your pet has to eat bones, garbage, or other hard matter. Other tests may be needed in cases of longterm constipation or obstipation.
Frequently asked questions
Disorders of the stomach and intestines in dogs?
The Merck Veterinary Manual covers this in the article linked on this page. Diseases that affect the stomach and intestines are common in dogs. They include infectious diseases such as bacterial, viral, and parasitic diseases… If your dog is unwell, contact your veterinarian — this page is educational, not a diagnosis.
Diseases of the stomach and intestines?
The Merck Veterinary Manual covers this in the article linked on this page. Diseases that affect the stomach and intestines are common in dogs. They include infectious diseases such as bacterial, viral, and parasitic diseases… If your dog is unwell, contact your veterinarian — this page is educational, not a diagnosis.
What are the common diseases of stomach and intestine?
The Merck Veterinary Manual covers this in the article linked on this page. Diseases that affect the stomach and intestines are common in dogs. They include infectious diseases such as bacterial, viral, and parasitic diseases… If your dog is unwell, contact your veterinarian — this page is educational, not a diagnosis.