Is Your Cat’s Infection Contagious? What Owners Need to Know

Bacterial infections are a common health issue among cats. They occur when pathogenic bacteria invade a cat’s body and begin to multiply, potentially causing illness. Some of the most prevalent bacterial infections in cats include:

Bartonella henselae – causes cat scratch disease

Campylobacter – causes gastrointestinal issues

Salmonella – leads to salmonellosis

Understanding bacterial infections in cats is important for pet owners. These contagious diseases can spread between cats, and some may even transmit to humans. Knowing the causes, symptoms, and treatment options allows cat owners to properly care for their pets’ health and take precautions against zoonotic infections that can spread to people. This article will provide an overview of the key bacterial infections found in cats, exploring their transmission, diagnosis, and recommended treatment protocols.

Common Bacterial Infections

Some of the most common bacterial infections in cats include:

cat with skin infection

  • Staphylococcus – Causes skin infections. Symptoms include itching, redness, pustules, crusting, and hair loss. Spread through contact with infected skin and surfaces. More common in kittens and cats with weakened immune systems (source).
  • Streptococcus – Causes upper respiratory infections. Symptoms include runny nose, sneezing, fever, and eye/nose discharge. Spread through saliva and nasal secretions (source).
  • Salmonella – Causes gastrointestinal infections. Symptoms include vomiting, diarrhea, fever, and lethargy. Spread through contaminated food and feces (source).

Bacterial infections often occur when a cat’s immune system is compromised by stress, poor nutrition, or other diseases. Maintaining good health is the best prevention.


Bacterial infections spread between cats in several ways. Common routes of transmission include:

  • Direct contact – Infectious agents can spread through activities like mutual grooming, sharing food bowls, or bites from fighting.
  • Respiratory droplets – Bacteria like Bordetella bronchiseptica can spread through sneezing and coughing.
  • Fecal-oral – Bacteria from feces can contaminate shared litter boxes, food, or water sources.
  • Environmental – Germs can live on surfaces like food bowls, bedding, and toys. Cats become infected when they come in contact with these contaminated items.
  • Vector-borne – Bacteria can spread via fleas, ticks, and other vectors that transfer pathogens between cats.

Kittens and cats with weakened immune systems are most susceptible. Overcrowding and poor sanitation also facilitate transmission between cats in the same household or facility.

Contagious to Humans?

woman washing hands after touching cat

Some bacterial infections that cats get can spread to humans, while others do not. Here are some of the common contagious ones:

Campylobacter – This bacterial infection causes campylobacteriosis in both cats and humans. Humans can get infected through contact with an infected cat’s stool, especially through ingesting contaminated food or water. Good hygiene like handwashing can help prevent transmission (CDC).

Bartonella henselae – Also known as cat scratch disease, this bacteria can be passed from cats to humans through bites and scratches. Cat fleas can also transmit it. It’s estimated that around 40% of cats carry Bartonella henselae at some point (Just Cats Clinic).

On the other hand, common cat bacterial infections like feline urinary tract infections are not contagious to humans.


There are several ways cat owners can help prevent bacterial infections in their feline companions. According to WagWalking source, the most important prevention method is maintaining good hygiene and sanitation practices. Litter boxes should be scooped daily and fully cleaned out weekly with soap and hot water to remove waste that can harbor bacteria. Food and water bowls should also be washed regularly.

Vetster recommends keeping cats indoors as much as possible, as bacteria are more common in outdoor environments. Use caution when introducing new cats to the household, as they may carry contagious bacteria. It’s also important to keep cats up-to-date on vaccines, deworming, and flea/tick prevention as parasites can transmit bacterial infections.

According to NASC Live, feeding cats commercially prepared food rather than raw food can help prevent bacterial contamination and illnesses like salmonella. Proper food handling when preparing raw food is also essential. Additionally, prompt veterinary care for wounds, dental disease, or other health issues can prevent secondary bacterial infections.

With good cat care habits, owners can greatly reduce the risks of bacterial infections in their feline friends.


To diagnose a bacterial infection in cats, veterinarians will first do a physical examination and observe the cat’s symptoms. They may ask about the cat’s medical history and when symptoms started to determine the timeline of the illness.

vet taking bacterial culture from cat

From there, the vet will likely run various diagnostic tests to identify the specific bacteria causing infection. These may include:

  • Blood tests to look for increased white blood cell count, which indicates infection.
  • Urinalysis to check for bacteria in the urinary tract.
  • Skin scrapings or biopsy to detect bacterial overgrowth on the skin.
  • Bacterial culture by swabbing the infected area and growing bacteria in a lab. This identifies the exact strain of bacteria present.
  • Fecal tests to diagnose bacterial infections in the gut.
  • X-rays or ultrasound imaging to find abscesses or other internal issues.

According to source, these tests help determine the cause and allow vets to diagnose bacterial infections accurately. The results also inform the proper treatment approach.


The main treatment for bacterial infections in cats is antibiotics. The specific antibiotic used will depend on the type of bacteria causing the infection, which is determined through either a culture or sensitivity testing. Some common antibiotics used to treat bacterial infections in cats include:





In addition to antibiotics, other medications may be prescribed to help manage the infection, such as:

Pain relievers to reduce discomfort and fever

Anti-inflammatories to reduce swelling and inflammation

Topical ointments for skin infections

Cats typically need to take the full course of antibiotics as prescribed by the veterinarian, even if they seem to be feeling better. Stopping antibiotics too soon can lead to recurring infection or antibiotic resistance. Close follow-up with the veterinarian is important to monitor how the infection is responding to treatment.

With appropriate antibiotic treatment and supportive care, the prognosis for bacterial infections in cats is generally good. However, prompt veterinary care is essential for proper diagnosis and treatment.



The prognosis for cats with bacterial infections depends greatly on whether or not they receive prompt veterinary treatment. According to, most bacterial infections in cats can be successfully treated with antibiotics and supportive care when diagnosed and treated early. However, if left untreated, the infection can spread, leading to more severe illness, permanent organ damage, and even death in some cases.

With aggressive antibiotic therapy, hospitalization, and good nursing care, many cats fully recover from serious bacterial infections within 1-2 weeks. However, relapses may occur if the full course of antibiotics is not completed. In severe cases that lead to septic shock or multiple organ failure, even with treatment the prognosis is grave and mortality rates are high.

Overall, the key to a good prognosis is early diagnosis and prompt treatment under a veterinarian’s supervision. Bacterial infections treated in this manner generally have an excellent prognosis. But without treatment, the outlook can quickly become poor to grave depending on the type and severity of infection.

When to See a Vet

If your cat has symptoms of a bacterial infection, such as lethargy, fever, skin lesions, diarrhea, or vomiting, a vet visit is necessary (source). Bacterial infections in cats can worsen quickly if left untreated, so it’s important to seek veterinary care as soon as you notice any concerning signs (source).

woman taking sick cat to the vet

Some indications that warrant an urgent vet visit include severe lethargy, very high fever (over 104°F), vomiting and diarrhea that lasts more than 24 hours, painful skin lesions, and respiratory distress. Left unchecked, bacterial infections can progress to sepsis, a life-threatening complication (source).

Your vet will run diagnostic tests like a bacterial culture to identify the type of infection and determine the most effective antibiotic treatment. They’ll also assess your cat’s overall health and may hospitalize them for IV fluids and care if the infection is advanced. Following your vet’s treatment plan is crucial for clearing the bacterial infection fully.


To summarize, bacterial infections in cats can be caused by many different types of bacteria, such as streptococcus, staphylococcus, salmonella, and E. coli. While some bacterial infections like skin infections may be transmitted through direct contact, most are not contagious to humans or other pets. However, some exceptions include kitten-associated gastroenteritis and cat scratch disease which can spread between cats and potentially to humans. It’s important to monitor cats for symptoms of bacterial infections like fever, lethargy, diarrhea, vomiting, and skin lesions. Take cats exhibiting concerning symptoms to a veterinarian promptly for diagnosis via bacterial culture and treatment with antibiotics. Preventing exposure to stray cats, keeping the environment clean, and maintaining good hygiene can help reduce risk. With proper care and veterinary treatment, most cats recover well from bacterial infections.

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