Salmonellosis is a highly contagious bacterial disease caused by many different types of the organism Salmonella
. It can affect any age or breed of dog, although it is most commonly seen in young puppies
and pregnant bitches. Salmonella is transmitted by contaminated water, food, or fomites (objects that can harbor transmit infection), and although it may cause severe clinical signs, individuals sometimes have no symptoms at all; Salmonella has been isolated from the feces of up to 25 percent of healthy dogs.
Several risk factors can render an individual more susceptible to Salmonella, including their overall health status and environment; concurrent disease; administration of certain medications like corticosteroids or chemotherapy, which causes suppression of the immune system; and exposure to the organism. There are several scenarios after infection, including gastroenteritis (diarrhea, with or without blood); subtle nonspecific signs, such as lethargy, depression, anorexia, diarrhea and fever; abortion; bacteremia and endotoxemia, systemic disease due to the presence of bacteria or their toxin in the bloodstream; and asymptomatic carriage.
Because the signs are so variable with Salmonella, many disorders must initially be considered when these individuals present. A host of infectious agents that cause gastrointestinal signs need to be differentiated from Salmonella. These include: Other bacteria – Clostridium, Campylobacter, Escherichia coli, Yersinia, Bacillus piliformis, Staphylococcus
Viral – parvovirus, coronavirus, rotavirus, paramyxovirus, adenovirus type I, infectious canine hepatitis
Fungal – Histoplasma, Pythium, Aspergillus
Rickettsial – Salmon poisoning in the pacific northwest, Rocky Mountain Spotted Fever
Intestinal parasites. Roundworms, hookworms, whipworms, coccidia and Giardia are a common cause of acute diarrhea, especially in young puppies. You may or may not be able to see them in the feces.
Hemorrhagic gastroenteritis (HGE) is a dramatic, potentially fatal disorder with no one known cause. It has a predilection for small breed dogs and is characterized by the sudden onset of profuse bloody diarrhea and occasional vomiting.
Small intestinal bacterial overgrowth (SIBO) is characterized by an overgrowth of normal intestinal flora (bacteria), and may mimic salmonellosis.
Acute gastroenteritis is an inflammation of the lining of the stomach/intestines, and is characterized by diarrhea and/or vomiting.
Dietary indiscretion can include eating spoiled food, overeating, ingesting foreign material, and sudden dietary changes. It is more common in dogs than cats, due to the indiscriminate eating habits of dogs.
Dietary intolerance associated with particular proteins, lactose, diets high in fat, and certain food additives can cause signs similar to Salmonella.
Drugs and toxins can cause acute diarrhea most often by either directly irritating the lining of the intestinal tract or disturbing the normal population of bacteria. Examples include nonsteroidal anti-inflammatory drugs such as aspirin, corticosteroids, antibiotics, anti-cancer drugs, insecticides, lawn and garden products, heavy metals, and certain heart drugs (digitalis).
Many metabolic diseases (kidney, liver, hypoadrenocorticism, hyperthyroidism) present with clinical signs of gastrointestinal disease, including diarrhea. Diarrhea may be bloody and often is accompanied by multiple other systemic signs in these cases.
An intussusception (telescoping of the bowel into itself) will often cause gastrointestinal signs. It is most often associated with the presence of inflammation, foreign bodies, parasites or tumors, and commonly causes diarrhea.
Pancreatitis – inflammation of the pancreas – can cause a spectrum of clinical signs including severe hemorrhagic diarrhea.
Exocrine pancreatic insufficiency (EPI) is a disorder in which the pancreas does not produce an adequate amount of digestive enzymes. This deficiency most often results in diarrhea secondary to maldigestion (poor digestion) and malabsorption (poor absorption).
Disorders That Cause Fever
Infectious disorders such as viral, bacterial, fungal, rickettsial and parasitic diseases
Immune or inflammatory diseases such as systemic lupus erythematosus (SLE), polyarthritis (inflammation of the joints), polymyositis (inflammation of the muscles), encephalomyelitis (inflammation of the brain and spinal cord), pancreatitis, and many others
Disorders That Cause Abortion
Infectious disorders such as viral, bacterial, rickettsial and parasitic diseases.
Endocrine disorders such as hypothyroidism
Drug administration such as chemotherapy, hormones, certain antibiotics
Severe stress or trauma
Placental or fetal defects