Is Cat Scratch Fever Contagious? What You Need to Know

What is Cat Scratch Fever?

Cat scratch fever, also known as cat scratch disease, is an infection caused by the bacteria Bartonella henselae. It is transmitted to humans through scratches, bites, or exposure to fleas from an infected cat. The bacteria are carried in the cat’s blood and saliva and can be introduced into a wound from a scratch or bite. Cat scratch fever is characterized by swollen lymph nodes near the site of the scratch or bite.

According to the Cleveland Clinic, cat scratch fever is an uncommon bacterial infection that you can get from a cat scratch or bite (source). The bacteria Bartonella henselae is the cause. When a cat harboring this bacteria scratches or bites a person and breaks the skin, the bacteria can get into the wound and cause an infection.

Symptoms

The most common symptoms of cat scratch fever include:

Is Cat Scratch Fever Contagious Between Cats?

fleas spreading cat scratch fever between cats

Cat scratch fever, also known as cat scratch disease, is caused by a bacterium called Bartonella henselae. Cats can transmit this bacteria between each other primarily through fleas. According to the CDC, the bacteria lives in the digestive tracts of infected fleas. When a cat scratches or bites another cat, the bacteria can be transmitted if the claws or teeth have been contaminated with flea feces.1

Kittens are more likely to get infected with cat scratch fever than adult cats. This is because kittens are more susceptible to fleas and their immature immune systems may not be able to fight off the bacteria as effectively. However, cats of any age can become infected if they come into contact with contaminated flea feces.2

The best way to prevent the spread of cat scratch fever between cats is through flea control and prevention. Regularly using flea medication on your cats, treating your home for fleas, and keeping cats indoors can help stop the transmission cycle. Vaccinating kittens may also provide protection against the disease.

Is Cat Scratch Fever Contagious Between Cats and to Humans?

Cat scratch fever, also known as cat scratch disease, is not contagious between humans. It can only be spread from an infected cat to a human via a bite or scratch. The disease is caused by a bacterium called Bartonella henselae that lives in cats’ saliva. When an infected cat bites or scratches a person and breaks the skin, the bacteria can enter the wound and cause an infection.

cat scratching person's hand

According to the CDC, cat scratch disease is not spread from person to person (CDC). The infection results from direct contact with an infected cat, usually a kitten or stray cat. Kittens under the age of one year are more likely to spread the disease since their immune systems are still developing. Stray cats are also more prone to being infected with Bartonella henselae.

While cat scratch fever is contagious between cats, it is not considered highly contagious among felines. Cats typically spread the bacteria through fleas or ticks. When an infected flea or tick bites a cat, the bacteria can be transmitted. Cats may also become infected through bites and scratches from other cats.

In summary, cat scratch fever is not contagious between humans. The only way for a human to contract the infection is through a bite or scratch from an infected cat resulting in direct transmission of the Bartonella henselae bacteria.

Diagnosis

Cat scratch fever is diagnosed through a combination of a physical exam to look for symptoms and laboratory tests on blood or lymph node samples. The doctor will perform a physical exam to check for signs of infection such as fever, rash, or enlarged lymph nodes near the scratch or bite. They will also ask about the person’s exposure to cats and any recent scratches or bites.

drawing blood for cat scratch fever test

If cat scratch fever is suspected, the doctor may order a blood test to look for antibodies against Bartonella henselae, the bacteria that causes the infection. Elevated antibody levels can help confirm the diagnosis. Another diagnostic method involves taking a biopsy of an enlarged lymph node and testing it for presence of the bacteria.

According to the CDC, polymerase chain reaction (PCR) tests on blood or lymph node samples can also detect the bacteria DNA and help diagnose cat scratch fever. In some cases, a biopsy allows microscopic examination of the lymph node tissue to look for granulomas, another sign of cat scratch disease.

With a combination of a thorough physical exam and lab tests on blood or lymph node samples, doctors can diagnose cat scratch fever and distinguish it from other causes of lymph node swelling and fever after a cat scratch.

Sources:

https://www.webmd.com/skin-problems-and-treatments/cat-scratch-fever

https://www.aafp.org/pubs/afp/issues/2011/0115/p152.html

Treatment

Cat scratch fever usually resolves on its own within 4-8 weeks without treatment. Antibiotics are sometimes prescribed for more severe cases of cat scratch fever.

According to the Cleveland Clinic, most people recover fully from cat scratch fever within a few weeks without any treatment [1]. The infection often goes away on its own as the immune system fights off the bacteria.

However, antibiotics may be used to treat cat scratch fever in people with more severe symptoms or complications. According to the American Academy of Family Physicians, antibiotics such as azithromycin or doxycycline may be prescribed if the infection causes prolonged fever, painful lymph nodes, or other concerning symptoms [2]. Immunocompromised patients are also more likely to require antibiotic treatment.

Overall, mild cases of cat scratch fever will generally resolve without medication within 1-2 months. But antibiotics can help speed recovery and prevent complications in severe cases involving high risk patients.

Prevention

There are a few ways to help prevent cat scratch disease and avoid transmission:

washing cat scratch wound

  • Avoid rough play with cats. Engaging in rough play where a cat may scratch or bite increases the risk of contracting the bacteria. Play gently and discourage biting and scratching.
  • Control fleas on cats. Fleas can transmit the bacteria between cats. Keep cats on a regular flea prevention medication.
  • Care for wounds immediately. If scratched or bitten by a cat, wash the wound thoroughly with soap and water. Apply antibiotic ointment and cover with a bandage.

Proper wound care helps prevent bacteria from entering the skin. It’s also important to watch for signs of infection and see a doctor if the wound becomes inflamed, painful, or has pus.

In addition, declawing cats is not recommended as a way to prevent cat scratch fever. Declawing can lead to behavioral problems in cats.

While there’s no vaccine available for humans, ensuring cats are up-to-date on their shots and avoiding rough play helps reduce the risk of transmission (CDC). Proper care if scratched or bitten can also lower the likelihood of developing cat scratch disease.

Risk Factors

Certain factors can increase your risk of developing cat scratch disease:

  • Kittens and young cats are more likely to carry Bartonella henselae bacteria than adult cats. Kittens under 1 year of age pose the highest risk.
  • People with weakened immune systems are more susceptible to developing cat scratch disease. This includes those with HIV/AIDS, cancer, organ transplants, or those taking immunosuppressant medications like steroids or chemotherapy.
  • Individuals with iron overload conditions like hemochromatosis are at increased risk due to the bacteria’s affinity for iron-rich environments.
  • People with chronic liver disease such as hepatitis or cirrhosis have a harder time fighting off infections.
  • Being scratched or bitten by a stray cat or kitten carries a higher risk than by a healthy house cat.
  • Cat scratches that break the skin pose a greater risk than superficial scratches.

According to the CDC, over 50% of cats carry Bartonella henselae at some point. While people of all ages can get cat scratch disease, it most commonly affects children and adolescents. Good hygiene and avoidance of rough play with cats can reduce the chances of transmission.

Complications

While most cases of cat scratch fever resolve on their own, rare cases can lead to chronic infection or other complications (Cleveland Clinic). The bacteria that causes cat scratch fever, Bartonella henselae, is known to sometimes persist in the body and cause continued infection.

In a small number of cases, cat scratch fever infection spreads to the brain or spinal cord leading to neurological problems like encephalitis, meningitis, or neuroretinitis. These neurological complications are estimated to occur in 1-7% of cat scratch fever cases (Mount Sinai). Symptoms may include severe headache, fever, neck stiffness, sensitivity to light, changes in mental status, seizures, tingling or numbness in the extremities, and vision changes or loss.

While rare, the potentially serious neurological complications associated with cat scratch fever emphasize the importance of seeing a doctor if any symptoms persist or worsen. Prompt diagnosis and treatment can help reduce the risk of chronic infection or other problems.

When to See a Doctor

You should see a doctor if symptoms of cat scratch disease persist beyond two weeks or get significantly worse. According to the CDC, it’s important to seek medical care if:

– The infected wound looks red, swollen, warm or discharging pus, indicating a possible skin infection

– Lymph node swelling and fever persists for more than two weeks

– New lymph nodes become swollen after the first week

– You develop a severe headache, stiff neck, sensitivity to light, nausea or vomiting

– You have a weakened immune system from cancer, HIV/AIDS, organ transplant etc.

Without treatment, symptoms can last from 2-4 months. Seeking early medical care can help relieve symptoms and prevent complications. Doctors can drain the lymph node if it becomes extremely large and painful. Antibiotics are not normally prescribed unless there are signs of a secondary skin infection. Otherwise, over-the-counter pain medication and warm compresses can help manage discomfort. Call your doctor promptly if cat scratch disease symptoms do not improve or get worse.

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