Cat Scratch Fever: What You Need To Know

By Chelsea Hunt-Rivera / November 29, 2018
cat scratch fever

While you may think “cat scratch fever” is just a catchy song from the 1970’s, you would actually be wrong. As a matter of fact, cat scratch fever is a real disease that humans contract from cats. If you are currently recalling the mass hysteria that accompanied diseases like West Nile Virus or Swine Flu you can go ahead and calm down. Cat scratch fever has been around for over a century and is typically very mild and treatable. You can rest assured your beloved cat is not suddenly a vicious threat. So, let’s debunk the mysterious cat scratch fever, shall we?

cat scratch fever

What is Cat Scratch Fever?

Also referred to as cat-scratch disease (CSD), cat scratch fever is a bacterial infection. Humans can contract the disease when scratched by a cat infected with the Bartonella henselae bacteria. Symptoms of CSD were first described in 1889, while the first clinical case did not occur until 1950. Cat scratch fever is unique because it is considered a zoonotic disease. Translation: cat-scratch disease can be transmitted between animals and humans. Cases of cat scratch fever can vary, but most of the time patients heal from the disease without even needing medical treatment.

What is Bartonella Henselae?

Bartonella henselae is the most well-known bacteria of the fifteen Bartonella species. Typically infecting red blood cells, Bartonella bacteria are referred to as intracellular parasites. Cat scratch fever is a direct result of contact with the Bartonella henselae bacteria. Cats typically contract the bacteria from fleas and ticks or from other infected cats. Bartonella infections are incredibly hard to diagnose in felines because they often show no signs of pain or infection. Interestingly enough, Bartonella is a very “stealthy” bacteria, as it were. Bartonella bacteria reproduce very slowly making it hard to catch. Furthermore, the Bartonella organisms can mask themselves from the immune system by “hiding” in the bloodstream in small, but powerful, numbers.

Bartonella Symptoms in Cats

First of all, cats infected with Bartonella often show zero symptoms. Even so, these seemingly healthy cats can still infect humans and other animals. Interestingly enough, the disease does not adversely affect cats, they merely act as a host to pass on the disease. However, in some cases, cats can and will display symptoms of Bartonella infection. Symptoms may include:

  • Inflammation of the gums (Gingivitis)
  • Sneezing/Nasal Discharge
  • Excessive eye-discharge or infection
  • Inflammation of the mouth (Stomatitis)
  • Chronic vomiting and/or diarrhea (inflammatory bowel disease)
  • Fever
  • Swollen glands
  • Lack of Appetite
  • Lethargy

If your cat is showing any one or a combination of these symptoms, be sure to visit your vet immediately. In the event that your cat is infected, you want to get them treated immediately as to prevent you and your families risk of infection.

Cat Eye Infection 

We would like to single out one of the above symptoms: eye infections. Many different health issues present themselves with an eye issue in cats. Cat eyes are especially unique, delicate, and intricate, making them especially susceptible to infection. While eye discharge is a common occurrence in healthy cats, should the discharge ever be excessive, or unusually colored, seek veterinary advise immediately. If your cat’s eyes are looking anything less than dazzling, something may be off. Here at SimpleWag, we pride ourselves on presenting in-depth thorough examinations on a variety of pet wellness topics. Therefore, you can take a look at our article on cat eye infections if you have any other questions or curiosities.

Bartonella Symptoms in Humans

Most often, cases of cat scratch disease are found in patients under 21 years old. Likely, this increase is because younger children often play too rough with cats, causing the cat to scratch or bite in defense. While cats remain silent carriers of cat-scratch disease, the human body is not so subtle. Signs and symptoms of cat scratch fever in humans include:

  • Swelling and redness at the bite/scratch side
  • Red, rounded, raised bump where scratch occurred (may resemble a bug bite)
  • Swelling of lymph nodes
  • Chills
  • Mild fever
  • Lethargy or fatigue
  • The general feeling of illness or discomfort
  • Lack of appetite
  • Myalgia (muscle pain)
  • Abdominal pain or cramps
  • Nausea

These symptoms can occur alone or in any combination of the above ailments. While certain symptoms can look and feel very uncomfortable, cat scratch fever is completely treatable and should cause no alarm to anyone infected. Read on to learn all about causes, prevention, and treatment!

Swollen Lymph Nodes in Neck on One Side 

One of the most painful and noticeable symptoms of cat scratch disease in humans are swollen lymph nodes. Typically occurring in the neck, lymph nodes will begin to swell one to three weeks after the inciting incident happened. Sometimes, scratches on or near the hand or arms can result in swollen lymph nodes under the armpit. Furthermore, if scratched on the lower half of the body, the swollen lymph node may occur near the groin area.

Considering lymph nodes job is to filter bacteria, it is no surprise CSD causes them to swell. When infected, swollen lymph nodes are spongy, round or oval bumps. Swollen lymph nodes can be 1/2 an inch to two inches thick in diameter. Additionally, they will often be warm, red in color, and filled with pus. Infected lymph nodes have been known to stay swollen for as long as two to four months post-infection.

What Causes Cat Scratch Disease? 

It is thought that between 20-40% of domestic cats carry the villainous bacteria at any given time. This number varies widely depending on a cats environment.

Causes in Cats

Cats contract the CSD-causing bacteria from infected fleas or ticks. Interestingly enough, cat’s do not become infected through flea or tick bites. Instead, infected fleas leave traces of feces throughout their host cat’s coat. When the cat goes to groom themselves, they ingest the infected feces and become carriers of the disease.

Furthermore, cats can be infected if scratched or bitten by another infected cat or animal.

parasites can cause cat scratch fever

Environmental Factors

Naturally, there are a number of factors that contribute to whether or not a cat is likely to come in contact with the disease. For example, outdoor cats are naturally more exposed to the elements and other cats that are infected. Additionally, outdoor cats tend to receive flea and tick medication less often, if ever. Consequently, cats that spend more time outside are infinitely more likely to come in contact with infected fleas.

Additionally, certain times of the year or specific climates are more prone to flea activity. Summertime and generally warmer climates offer a cozy breeding ground for fleas and ticks.

Causes in Humans

Simply put, humans get cat scratch disease from infected cats. That is not to say simply petting an infected cat spreads the disease. Rather, a bite or scratch that breaks the skin leads to infection. In some cases, a friendly lick can be the culprit as well. That is if the saliva comes in contact with an existing wound or the eyes.

While a healthy sense of play is encouraged in cats, you should always be careful to avoid painful, and possibly disease transmitting scratches. Infected humans cannot pass the disease to other humans.

Cat Scratch Fever in Dogs

At this point, we would like to point out that while called “cat scratch fever”, CSD can actually occur in canines as well. Considering dogs can contract the Bartonella bacteria, naturally, they can also spread it. Similar to cats, a blood-drawing bite or scratch from an infected dog can cause CSD in humans. Additionally, an infected dog’s saliva on an open wound can lead to infection.

It is important to note canines ability to contract and pass cat scratch fever for those families that have more than one animal. If you own a cat and a dog, know that the disease can be passed amongst them, and possibly to you and your family as well. While cats are silent carriers of the Bartonella bacteria, dogs, on the other hand, are less cryptic about their infection.

Symptoms of Cat Scratch Fever in Dogs

Fortunately, symptoms of Bartonella in dogs are far more obvious than in cats. Symptoms of “cat scratch fever” in dogs may include:

  • Swollen or inflamed lymph nodes
  • Fever
  • Inflammation of the eyes and/or nose
  • Enlarged spleen and liver
  • Lameness
  • Vomiting and/or diarrhea
  • Seizures
  • Nosebleed
  • Coughing
  • Arthritis

cat scratch fever in dogs

Interestingly enough, dogs display many symptoms similar to those seen in humans. Furthermore, the process of diagnosing, treating, and preventing cat scratch fever in dogs is exactly the same as it is for cats. Read on to learn how to do just that.

Diagnosing a Bartonella Infection

As you may have inferred, diagnosing Bartonella in felines is incredibly difficult. Considering infected cats often show no signs of infection or sickness, vets typically do not even know to look. However, if you suspect infection, there are ways to test for Bartonella infection.

Diagnosing Infection in Cats

If you suspect your cat has contracted Bartonella, your vet can run a number of tests in order to diagnose. Better yet, you should have your cat tested annually anyway to rule out any other diseases or infections. Tests may include:

  • Urine test – To determine loss of proteins or the presence of a urinary tract infection (UTI)
  • Electrolyte and Chemistry tests – Confirm healthy functioning of the liver, kidney, and pancreas. These tests also report the balance of sugar, salt, and water in your cat’s system
  • Blood test – Tests for infection, anemia, inflammation, and/or low platelets
  • Thyroid test
  • General screening for Feline Leukemia Virus and Immunodeficiency Virus

Blood, fluid, and tissue samples have to be submitted for specialized testing, which, as you may imagine, can get expensive. Furthermore, results may be inconclusive when looking for Bartonella, specifically because it takes so few cells to cause the infection.

Diagnosing Infection in Humans

Cat scratch fever is infinitely simpler to diagnosis in human patients. Typically, a doctor can tell by looking at the scratch site or feeling the lymph nodes. However, sometimes doctors will order a simple blood test to confirm their diagnosis of cat scratch fever.

Bartonella Treatment

Fortunately, cat scratch fever is not a violent disease in cats or humans. Considering felines are not adversely affected by the bacteria, typically no treatment is necessary. Cats can live long, healthy lives while the bacteria lies in their system. Conversely, cats suffering from weakened immune systems or preexisting conditions will likely need treatment. Any bacteria or infection thrust upon an immune system in poor health can mean trouble. In that case, consult your vet for the best medication for your cat’s unique needs.

Cat Scratch Fever Treatment for Humans

More often than not, patients who display signs of cat scratch fever get better without any medical treatment required. Better still, people having been infected with CSD are then immune for life, just like with the chicken pox.

If symptoms persist for longer than a month, a doctor may prescribe antibiotics to cleanse the body of infection. In some cases, people may opt to get their swollen lymph nodes aspirated to remove the excess pus and relieve lingering pain. Additionally, a hot compress can help reduce pain and swelling of the lymph nodes.

In incredibly rare cases, the infection can travel to the liver, bones, or other organs. Therefore, a trip to the doctor is advised if symptoms are especially severe or persistent.

Weakened Immune Systems, Listen Up!

If you or a loved one is immunocompromised (aka has a weakened immune system) it is recommended that you stay away from cats unless cleared of the Bartonella bacteria. This is important to note because while CSD is a typically mild disease, any virus, bacteria, or infection is far more viscous on a weak immune system. Causes of a weakened immune system include, but are not limited to:

  • Chemotherapy
  • Cancer or any kind
  • HIV
  • Diabetes
  • Malnutrition
  • Age (babies/children/older people are all cases of weaker immune systems)
  • Pre-existing diseases and conditions

We want to point this out because it is not uncommon for older people or those suffering from illness, to get a cat for therapy or companionship. While that is a great idea, be sure to take caution and make sure the cat has a clean bill of health first.

How to Prevent Cat Scratch Fever

For humans, be cautious when petting or playing with stray, or unfamiliar cats. As previously mentioned, symptoms of CSD in felines are very mild. Cats may appear totally healthy, even when they are carrying the infection. In any case, if and when you get bitten or scratched, always wash the wound thoroughly with soap and water immediately. Furthermore, as a cat owner, in order to best prevent cases of cat scratch fever, there are some precautions you can take with your own cat.

How to Keep Your Cat Infection-Free

While the Bartonella bacteria is close to undetectable in cats, there are actions you can take to prevent the spreading of disease.

Regular Grooming

As a diligently caring cat owner, there are necessary actions to keeping your cat healthy. To help prevent the spreading of Bartonella, always keep your cat’s nail trimmed. This may come as a surprise to you, but you should actually trim your cat’s nails every ten days. If your cat isn’t a fan of the nail clippers, there are plenty of tips and tricks to help. Keeping their nails trimmed will help prevent the likelihood of skin-breaking scratches. Additionally, cat scratching posts work wonders on naturally manicuring feline nails.

Flea Prevention in Cats

Considering cat scratch fever is mainly caught from infected flea and ticks, prevention is essential. Talk to your vet about what flea and tick prevention is best for your cat. Be cautious about self-prescribing over-the-counter options, as they may not be safe for your cat. Always get vet approval before administering any new medication. Typically, an oral or topical medication will need to be administered on a monthly basis.

Furthermore, you can help prevent the spreading of fleas by keeping your home clean. Vacuum rugs, couches, and carpeted areas regularly. Wash linens often, and keep doors and windows closed, especially during the hotter times of the year. If you have any other dogs or cats, keep an eye on their coats as well to prevent the spreading of fleas.

Overall Feline Health

In order to ensure a long and healthy life for your cat, be sure to make time for annual check-ups. As previously mentioned, the Bartonella bacteria shows very little signs and symptoms. Regular vet visits will help monitor your cat’s condition and keep them up-to-date on all shots and other preventative measures.

Furthermore, if your cat is an indoor cat, it is best to keep it that way. This will reduce contact with fleas and/or getting in possibly harmful fights with other animals.

Kids and Cat Scratch Fever

Those with kids may currently be worried about their safety around your household feline friend. Worry not, while kids are the most common cases of CSD, you do not need to get rid of your beloved family feline. Not only is the disease incredibly mild, but it is uncommon, to begin with. Even so, here are some kid-specific tips for preventing cat scratch disease in your family.

Child Safety Tips

First of all, teach your kids to avoid stray or unfamiliar cats (or animals of any kind). Kids are naturally curious, and if you have a cat at home they may think all cats are as friendly as yours. However, stray cats often do not like to be touched and can bite or scratch in defense. When playing with your family cat, be sure your kids know to be gentle and avoid rough play. Cats are natural predators and will bite or scratch due to instinct.

Finally, always encourage your kids to wash their hands after handling any animal, especially before eating. In the event your child is bitten or scratched, wash the area with soap and water immediately.

you can prevent cat scratch fever

Cat Scratch Fever: Final Thoughts 

With roughly 600 million felines in the world and 75 million in the United States alone, you are likely to find yourself face to whiskers with a cat at some point or another. While only a small fraction of those cats carry the Bartonella bacteria, still approximately 22,000 people get cat scratch fever in America annually. Fortunately, cat scratch fever is no cause for alarm in felines or humans. Easily treatable and mild in most cases, you can rest assured that your beloved cat is not an enemy. So go forth and play with your cat! Just try not to get scratched!


About the author

Chelsea Hunt-Rivera

Chelsea Rivera is a Dedicated Pet Parent who loves to create amazing content for pet owners and is helping change pet wellness as the Head of Content for