What is salmonellosis?
Salmonellosis is a bacterial infection caused by the Salmonella bacterium which typically lives in the intestines and is shed via the feces. Salmonella is a common cause of enteritis (inflammation of the intestines) with associated vomiting and diarrhea. Infection occurs in a wide range of animals which includes humans, wild animals, cats, dogs, farm animals, birds, fish, reptiles, and amphibians.
There are over 2,400 serotypes of the genus Salmonella which live in the intestinal tracts of the infected host. Salmonellosis is rare in cats; however, it is of particular importance because it is a zoonotic disease, which means one that cats can transmit to humans.
Salmonella acquired its name from US veterinarian Dr Daniel Elmer Salmon, which was named in his honour by an assistant, Theobold Smith who first discovered it in 1885.
Not only did Dr Salmon give his name to the bacteria, but he was also awarded the first doctorate of veterinary science in the United States.
Salmonellosis causes a reddening of the intestinal mucosa, 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 body’s defences either contain the bacteria and its toxins or it invades the bloodstream (bacteremia) and then onto other organs such as the liver and spleen.
It can cause abortion in pregnant females.
Risk factors include age (kittens and geriatric cats are at increased risk), immunocompromised cats and cats on antibiotics which may wipe out healthy bacteria in the intestinal tract.
How is salmonella transmitted?
Cats acquire salmonellosis most often via contaminated food, water or infected prey. Salmonellosis in cats is also known as 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.
- Consumption of contaminated food (including raw meat, commercial cat food, and eggs) and water.
- Salmonella bacteria can survive on objects (food bowls, toys, etc.) for long periods.
Symptoms of salmonella
Most infected cats will be asymptomatic (subclinical carrier state).
Salmonellosis is rare in cats; as they appear to have a natural immunity to the bacteria. Risk factors include the strain (some are more pathogenic than others), cats in high-stress situations and environments such as shelters, immunocompromised cats, general poor health status, hospitalised animals, young and old cats.
Kittens, senior cats, and cats, with weak immune systems are more likely to develop clinical signs.
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
- Rapid heart rate
The 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.
- Bacterial cultures from rectal swabs or fresh feces.
- Blood culture to isolate the bacteria if bacteremia.
- Biochemical profile, complete blood count, and urinalysis to evaluate the overall health as well as check organ function and determine how dehydrated your cat is. Most blood values are normal, although reduced white blood cell count, low platelets and non-regenerative anemia may be present in severely affected cats. Cats with severe vomiting and diarrhea may also have electrolyte imbalances.
Uncomplicated cases may be treated on an outpatient basis, which may include a bland diet or restrict food for 24-48 hours.
Moderate to severe salmonellosis:
- Cats with clinical signs will receive fluids to treat dehydration and replace lost electrolytes.
- Blood transfusion for severe cases where septic Salmonella has developed.
- 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 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?
There are very few reports of human infection from cats, and people usually become infected via contaminated food.
However, there is still a risk that when the cat grooms, bacteria in the saliva transfer onto the coat, which can contaminate the environment or when bacteria pass in the cat’s stool. Take care when handling a cat with Salmonella as well and decontaminate the environment and always wash your hands with soap and water.
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.
- Sterilise litter trays with bleach (1:10 dilution) and cold water (hot water decomposes the active ingredient).
- 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 salmonellosis.
- Keep your cat’s food and water bowls separate from utensils that will be used for people. Cats should have their own bowls and cleaning utensils to wash the bowls with.
- Remove uneaten wet cat food after 20-30 minutes.
- Bleach is the best method to kill Salmonella bacteria in the environment at a ratio of 1:32. Clean surfaces before the application of bleach as organic matter deactivates it.
- Leave the bleach solution on surfaces for a minimum of 10 minutes. Rinse thoroughly with clean, fresh water after contact with bleach and dry well.
- 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.