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Understanding Your Pet's Medical Diagnosis


What is salmonellosis?

Salmonellosis is a bacterial disease caused by Salmonella. Many types of Salmonella exist. Salmonellosis can be characterized by intestinal disease (such as diarrhea), abortion, or generalized infection (septicemia). The disease varies widely in intensity; infected animals may be carriers with no signs of illness, or they may have mild, moderate, or severe illness and debilitation. Infection with no signs of disease is more common than actual illness.

What causes salmonellosis?

Any one of more than 2,000 types of Salmonella can cause salmonellosis. The bacteria are ingested and colonize in the small intestine. Salmonella may remain in the intestine or may spread throughout the body via the lymphatic and circulatory systems. The disease is more common in young cats, young or pregnant dogs, and adult animals subject to stress (such as overcrowding, hospitalization, dietary changes, or travel). In general, cats have a high natural resistance to salmonellosis; however, stressed cats are at higher risk. The sources of the bacteria include:

What are the signs of salmonellosis?

The signs of salmonellosis vary. Many infected animals have no sign of disease. Some animals may have vomiting, diarrhea, or dehydration if the bacteria remain in the intestines and does not spread. More serious disease occurs if the bacteria get into the blood stream, causing widespread blood infection. From the bloodstream, the bacteria can cause severe damage to body organs, abnormal blood clots or blood disorders, and death.

Other signs of salmonellosis include fever, lack of appetite, fatigue, and weakness. Vaginal discharge or abortion may be seen in dogs. Some animals may have diarrhea containing mucus or blood, abdominal pain, and pale gums and tongue. Weight loss may be apparent. Recovering animals may have intermittent diarrhea for 3 to 4 weeks and may shed Salmonella in the stool for 6 weeks or longer. Cats may exhibit a syndrome of long-term (chronic) illness with persistent fever and vague, nonspecific signs (and no vomiting or diarrhea).

How is salmonellosis diagnosed?

Salmonellosis is diagnosed by a good history, a thorough physical examination, blood tests, and bacterial cultures of bowel movement, blood, or joint fluid. Complete blood tests (CBCs) may show abnormalities such as anemia (low red blood cell count). Blood chemistries may reveal fluid and electrolyte imbalances or other abnormalities. Bacterial culture of bowel movement or rectum will be positive for Salmonella. Blood and joint fluid cultures may be positive for Salmonella.

How is salmonellosis treated?

The treatment for salmonellosis depends upon the severity of the clinical disease. Pets with advanced disease, or newborns and young animals with debilitating diarrhea are hospitalized. Animals should be isolated because they may be shedding large numbers of Salmonella in their bowel movements. Seriously ill animals should rest and be kept warm. Food is restricted for 24 to 48 hours, and then food is introduced gradually. A highly digestible, low-fat diet is recommended. Antibiotics are not given to animals that are carriers of the bacteria but have no signs of illness. Antibiotics are not indicated if the infection is confined to the intestines. Supportive care is given. Fluids are administered either by mouth (orally) or through a vein (intravenously) as needed for dehydration. Drugs may be given to protect the intestines. Severely ill animals may be treated with plasma transfusions and steroids. Antibiotics are based on culture and sensitivity test results.

After recovery, a bacterial culture of the stool may be repeated monthly for a few months to assess development of a carrier state. The pet's contacts with other animals and people should be limited to minimize spread of the bacteria. Salmonellosis can be prevented with proper nutrition (no raw meat), sanitary conditions, and proper storage of food. Overcrowding of animals in pounds, shelters, kennels, or research labs should be minimized. Good hand washing can minimize the risk of infection to people.

What is the prognosis for animals with salmonellosis?

If the infection remains in the intestines, the prognosis (outcome) for animals with salmonellosis is excellent. Animals frequently recover with good nursing care. Severely ill animals can die without treatment.

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