What Is Cat Scratch Fever?
For many of us, “cat scratch fever” brings to mind Ted Nugent’s ’70s rock classic. But cat scratch fever is more than just a catchy song; it’s a condition called bartonellosis. The responsible bacteria, Bartonella henselae, is most commonly spread to humans by a cat scratch and often results in a fever.
Bartonella henselae is very common in cats, especially young cats and kittens with fleas. Other animals, like dogs and rabbits, can also be infected. Cat scratch fever, or cat scratch disease, does not result in illness in most cats that come into contact with the bacteria. However, it can pose a risk of disease to humans through bites and scratches.
Symptoms of Cat Scratch Fever
Most cats with cat scratch fever are asymptomatic, meaning they have no clinical signs and appear normal. Very rarely, a cat may have signs of disease, including:
Enlarged lymph nodes
Transient fever, lethargy, and/or anorexia
Bacterial heart infection
Remember, most cats with cat scratch fever are not sick and do not show signs of disease. Humans, on the other hand, more frequently manifest symptoms of cat scratch fever. These are the most commonly reported:
Pustule on the site of the scratch
Enlarged lymph nodes
Causes of Cat Scratch Fever
Cat scratch fever is caused by a bacteria spread in the feces and digestive products of fleas, called flea dirt. Cats become infected when they have a flea infestation and scratch themselves with claws contaminated with the Bartonella bacteria from flea dirt. The same bacteria has been found in ticks.
Humans become infected with cat scratch fever when they are bitten or scratched by cats and that wound is contaminated with infected flea feces. Cats with fleas will often scratch and chew on themselves, getting the bacteria on their claws and in the mucus membranes of their mouths.
How Veterinarians Diagnose Cat Scratch Fever
Cats are very rarely tested for cat scratch fever, as most infected cats never show signs of the disease. Occasionally, a cat that is going to be a blood donor may be tested.
Most veterinarians will make a presumptive diagnosis based on history of exposure. If they decide to test for cat scratch fever, they may recommend repetitive testing intervals to increase the likelihood of capturing the bacteria while the cat is shedding it in its blood.
What To Do If Your Cat Is Diagnosed with Cat Scratch Fever
If your doctor has diagnosed you or a family member with cat scratch fever, it is important to remember that while cats are likely the source of the infection, they are unlikely to become sick themselves. Most infected cats’ immune systems will handle the infection on their own and do not require a veterinary visit for intervention.
While most cat scratches do not result in cat scratch fever, it is important to clean any and all cat scratches and/or bites thoroughly. If you or your child are scratched by a cat and develop a bump on the site of the scratch, followed by swollen lymph nodes and/or a fever 1-3 weeks later, talk to your medical provider about next steps.
Treatment of Cat Scratch Fever
Cat scratch fever rarely requires treatment in a cat. Most cats' immune systems will manage the infection on their own without any intervention.
In rare instances where cats become sick with the disease, they may be treated with antibiotics. Sometimes treatment is pursued when cats that have been diagnosed with the disease are living with immunocompromised humans. Antibiotic therapy is the treatment of choice, for a minimum of 3 weeks. Treatment can be challenging, as the Bartonella bacteria often develops resistance to antibiotics.
Treatment of Cat Scratch Fever in Humans
Most cases of cat scratch fever are self-limiting and resolve on their own without treatment. Some cases require antibiotic therapy. Uncommonly, some people may develop a more chronic serious form of the disease. These patients tend to be immunocompromised with an underlying disease that affects how well their immune system is able to function.
If you believe you may be suffering from cat scratch fever, talk to your medical provider about recommended next steps.
Recovery and Management of Cat Scratch Fever
Most cats affected by cat scratch fever show no signs of the disease and recover uneventfully on their own. The relatively few cats that develop a mild fever and/or swollen lymph nodes may require a few days of rest before their immune system manages the infection. If your cat is put on antibiotics for cat scratch fever, be sure to complete the course prescribed. Antibiotic therapy may last for several weeks.
Humans infected with cat scratch fever will generally recover on their own over a period of 2-8 weeks. However, lymph node enlargement may persist for several months. Individuals whose immune systems are compromised may develop more serious infections and experience more complications with longer recovery periods.
Prevention of Cat Scratch Fever
The best way to prevent cat scratch fever in your pets and yourself is to keep your cat on regular flea and tick prevention. Cat scratch fever is spread primarily by cat scratches and bites where the claws and/or mouth are contaminated with flea dirt. Eliminating fleas will dramatically decrease your cat’s and your own risk of becoming infected with cat scratch fever.
Should you be scratched or bitten by a cat, it is important to clean the wound thoroughly with soap and water. Even if your cat is not infected with cat scratch fever, there are many other bacteria species that can live in a cat’s mouth or claws.
Individuals who are immunocompromised by cancer, HIV, or other immune system diseases should still be able to have a pet cat. To prevent cat scratch fever, follow these simple steps:
Keep all pets in your household on regular flea and tick prevention year round.
Avoid letting cats go outside, where they have increased exposure to fleas and the Bartonella henselae bacteria
Try not to encourage rough play with your cat that increases your risk of being bitten or scratched.
In the event that you do receive a bite or scratch from your cat, clean the wound thoroughly with soap and water.
Keep your cat’s claws trimmed so they are less likely to break skin in the event of a scratch.
Brooks, W. Veterinary Information Network. Bartonella and cat scratch fever. August 2021.
US Centers for Disease Control and Prevention. Bartonella. January 2020.
Guptill, L. DVM360. What do we really know about feline bartonellosis? August 2009.
Walden, L. DVM360. CDC report of cat-scratch disease in the United States. December 2016.
Featured Image: iStock.com/Linda Raymond
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