Most animals harbour bacteria in their intestines. This is normal and healthy. These bacteria may include E coli, Campylobacter and salmonella. Bacterial illness results when an overwhelming number of bacteria, or unfamiliar bacterial strains, defeat the body's normal defences. While many dogs harbour salmonella, they may never show no signs or have trouble with it. When they get salmonellosis, the symptoms are hard to miss and may be severe.
Salmonella bacteria has more than 2,000 types. Many are rare or specific to particular hosts, such as certain bird species and reptiles. The most common type of salmonella is Salmonella enterica, which is found in most animals and lies dormant in soil.
Dogs usually get salmonella poisoning from tainted meat, commercial dog food and treats. Many dry dog foods and commercial treats, including rawhide bones and pig ears, are laden with salmonella bacteria and are often recalled by manufacturers or the FDA. Most animals--including humans--shed salmonella in their faeces, so dogs can also get salmonella poisoning by eating bacteria-laden excrement.
Dogs that harbour salmonella but have no symptoms are called subclinical carriers. They will shed the bacteria when defecating: one reason it is wise to wash your hands after cleaning up the yard. Salmonella may also be found in a dog's saliva. Salmonella is a zoonotic disease, meaning humans can catch it from animals.
Mild Salmonella Poisoning
Mild salmonella poisoning (salmonellosis) is characterised by diarrhoea and sometimes vomiting. The diarrhoea may be green or yellowish. A healthy dog with a good immune system may fight off mild salmonellosis without medical intervention. Puppies or dogs that are ill or very elderly are more susceptible and may have more severe symptoms.
A dog can have a low-level, chronic case of salmonella poisoning, with the only symptom being intermittent diarrhoea.
In more severe cases, the dog will have bloody or watery diarrhoea. She will also be lethargic and unwilling to eat or drink and may vomit immediately if she does. Other signs are stomach pain and a fever. A dog with these symptoms is very ill and needs veterinary attention immediately. Severe salmonellosis can kill weak dogs or young puppies when dehydration leads to organ failure.
To check for dehydration, pinch up a fold of skin between the dog's shoulder blades. The skin should snap back to position as soon as released; if not the dog is dehydrated. Also check his gums. They should be shiny and slick with saliva. Dry, sticky gums are another sign of dehydration.
Diagnosis and Treatment
Any time your dog is showing signs of gastrointestinal upset, take her to the veterinarian. Bring a fecal sample with you. If you don't, the vet will have to get an anal swab from the dog, which is unpleasant and stressful. Because many things can cause diarrhoea and vomiting, the vet will examine the fecal sample for signs of parasites or bacterial overload.
Treatment is usually simple. The vet will probably prescribe antibiotics along with a bland diet and send the dog home. More severe cases could require hospitalisation for intravenous fluids and antibiotics.