Salmonellosis is a bacterial infection caused by the Salmonella bacterium. It is a common cause of enteritis (inflammation of the intestines) with associated vomiting and diarrhea. Salmonella can affect a wide range of animals including humans, wild animals, domestic pets, farm animals, birds, fish, reptiles, and amphibians.
There are almost 2,000 serotypes of the genus Salmonella which live in the intestinal tracts of the infected host. Salmonella appears to be relatively uncommon in cats, however, it is of particular importance because it is a zoonotic disease, meaning one which can be passed from animals to humans.
Salmonella acquired its name from US veterinarian Dr Daniel E. Salmon, which was named in his honor by an assistant, Theobold Smith who first discovered it in 1885.
The geographical distribution is worldwide.
Clinical features of salmonella:
Salmonellosis causes a reddening of the intestinal mucosa as well as reddening of the mesenteric (membranous sheet attaching various organs to the body wall, especially the peritoneal fold attaching the intestine to the dorsal body wall) and the lymph nodes. At this point, the bacteria and or their toxin are either contained by the body's own defenses or invades the bloodstream (bacteremia) and then onto other organs such as the liver and spleen.
It can cause abortion in pregnant females.
How do cats become infected with salmonella?
Cats are most commonly infected via contaminated food or catching infected animals. In fact, Salmonellosis in cats has been called "songbird fever" due to its association with cats acquiring infection from hunting and consuming birds.
- Salmonella can be found in feces and the saliva of an infected host. Cats become infected from catching and eating infected prey.
- Cats can become infected by consuming contaminate food (including raw meat, commercial cat food, and eggs) as well as water.
- Salmonella can survive on objects (food bowls, toys etc) for long periods of time.
What are the symptoms of salmonellosis?
Most cats infected with salmonella have what's known as subclinical carrier state. This means that they have been infected but only very mildly and don't display any clinical manifestations of the disease. Salmonellosis isn't seen very often in cats and it is believed they have a natural immunity to the bacteria. Risk factors which can make a cat more susceptible to salmonellosis include the strain of salmonella (some are more pathogenic than others), cats in high stress situations and environments such as shelters, cats whose natural resistance has been compromised due to another infection, general poor health status, hospitalised animals, young and old cats.
Kittens, senior cats and cats, with weakened immune systems are more likely to be clinically affected than healthy adult cats. Symptoms of salmonellosis appear after 2 - 4 days of exposure and can include:
- Diarrhea (may or may not contain blood or mucus)
- Poor appetite (anorexia)
- High fever
- Abdominal pain
- Weight loss
How is salmonellosis diagnosed in cats?
Your veterinarian will perform a complete physical examination of your cat and obtain a medical history from you including recent food your cat has consumed as well as a history of hunting. He will need to perform some diagnostic tests including:
- Bacterial cultures from rectal swabs or fresh feces.
- Blood culture to isolate the bacteria if bacteremia is suspected.
- Complete blood count, biochemical profile, and urinalysis to evaluate the overall health as well as check organ function and determine how dehydrated your cat is. Most blood values return back normal, although reduced white blood cell count or anemia may be present in severely affected cats.
How is salmonellosis treated?
If the infection isn't severe then supportive care will be given at home. Food and water are restricted while vomiting and diarrhea are present.
If hospitalisation is required your veterinarian will administer fluids to treat dehydration and replace electrolytes.
In severe cases, a blood transfusion may be required in cats who have developed septic salmonella.
It seems there is some controversy over the use of antibiotics to treat simple cases of salmonella enteritis (intestinal inflammation) with diarrhea in cats, suggesting that antibiotics can actually favour the growth of antibiotic-resistant strains of salmonella. Antibiotics (sulfa) are therefore reserved for severely ill cats.
Can I catch salmonella from my cat?
Cats have been found to shed the serotype of salmonella which is pathogenic to humans. However, there are very few (if any) reports of human infection from cats. There is a much, much greater risk of becoming infected via infected food.
Bacteria in the cat's saliva can be transferred onto the cat's coat during grooming and quickly contaminate the environment, therefore, extreme care must be taken when handling a cat with salmonella as well as ensuring the environment is properly decontaminated.
Reducing the risk of salmonella infection:
- Wash your cat's food bowls after every meal. If you have more than one cat feed separately and avoid them sharing water bowls.
- Wash your hands after handling your cat.
- Wear rubber gloves when cleaning out litter trays.
- When emptying litter trays, clean with bleach and hot water. Rinse well.
- Young children, seniors and people with a compromised immune system are at particular risk and should avoid any contact with a cat who is recovering from salmonella.
- Keep your cat's food and water bowls separate from utensils which will be used for people. They should have their own bowls and sponge to clean the bowls with.
- Remove uneaten wet cat food after 20-30 minutes.
Killing salmonella in the environment:
- Bleach is the best method to kill salmonella bacteria in the environment. A ratio of 1:32 can be used. Surfaces should be cleaned before the application of bleach as organic matter can deactivate it.
- Bleach should be left on surfaces (for example litter trays) for a minimum of 10 minutes to ensure disinfection. Rinse thoroughly with clean fresh water after contact with bleach and dry well.
- Always wear protective gloves when handling bleach and make sure the environment is well aired.
- Administer all medications as prescribed.
- Follow up appointments will be necessary to perform fecal cultures.
- Your veterinarian may recommend an easy to digest, low-fat diet while your cat is recovering. Chicken breast poached in water is highly palatable to cats and is easy on their gastrointestinal tract.