Contrary to what the name suggests, “cat scratch disease” is a human disease. Read here the most important things about symptoms, therapy, and effective prevention.

Cat scratch disease in humans: what is it?

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Cat scratch disease is an infection caused by the bacteria Bartonella henselae or Bartonella clarridgeiae.

The carriers to humans are almost always cats that have had close contact with the biped.

The French pediatrician Robert Debré gave the disease its name “maladie des griffes du chat” because the symptoms appeared after scratches. But the bacteria can also transmit bites or licks.

Infected velvet paws themselves show little or no symptoms. Researchers observed that some infected animals had less appetite or increased temperature. This is hardly noticeable for cat owners in everyday life.

Cat scratch disease is also associated with few symptoms for most people. Further names for them are: “Cat scratch fever”, “Cat scratch lymphadenitis” or the English name “cat scratch disease”.

How contagious is cat scratch disease?

Infected cats transmit the bacteria to humans by scratching, biting, and licking. The bacterium gets to the claws, for example, when the velvet paw scratches itself. Many carrier cats do this because: The bacterium gets into their bodies through fleas. If humans have a small skin wound and the cat licks it, humans can become infected.

Estimates assume that ten percent or more of all cats in Germany carry the bacterium. It is uncertain whether fleas can transmit cat disease directly to humans. Occasionally there are people who get cat scratch disease without having had to contact four-legged friends.

However, children are most often affected.

Because they have close contact with cats living in the household and do not yet have a fully developed immune system. Since the disease cannot be transmitted from person to person, the cat-scratch disease is rare.

Symptoms of cat scratch disease: testing lymph nodes

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Cat scratch disease is almost always preceded by a scratch injury, a bite, or close cat contact in combination with a small wound. Symptoms in the affected person begin three to ten days after contact. These include:

  • a pea-sized papule or nodule on the injured area
  • swelling of the lymph nodes in the neck or armpits
  • mild fever and pain
  • Loss of appetite
  • malaise

Additional symptoms appear in up to 14 percent of those affected:

  • conjunctivitis with palpable nodules
  • neurological symptoms such as cramps, paralysis
  • severe pain in the limbs and headache

Particular caution applies to risk groups: people with heart valve damage can develop an inflammation of the inner lining of the heart from cat-scratch disease. In AIDS patients, the disease can be life-threatening because the immune system cannot fight it. Bartonella henselae can cause bacillary angiomatosis in them. This is a skin disease that is accompanied by reddish papules or nodules distributed over a large area.

The organs can also be affected by a severe course. Liver damage or meningitis can occur. Blood poisoning can also occur in immunocompromised people.

Cat scratch fever: diagnosis through blood values

First, the medical practitioner will examine the patient thoroughly. This includes clarifying possible contact with cats. The doctor will also look at the swollen lymph nodes and the wound.

But the diagnosis cannot be made without a tissue or blood sample. The doctor usually uses a blood sample for this. Because if the body is attacked by bacteria, the immune system formulates a suitable response: the antibodies. If the cat-scratch disease is suspected, the doctor can test the blood for antibodies.

Another possibility is to take a sample from an infected lymph node. The bacteria are to be detected in this sample. Sometimes further work-up requires an ultrasound scan of the affected lymph nodes.

Cat scratch disease: therapy

In most cases, cat-scratch disease heals on its own after around two to three months without any consequences.

In support of this, those affected can treat the infection site with heat and, if necessary, take painkillers. If the symptoms don’t go away on their own, the doctor may prescribe antibiotics. This also applies to risk groups with a weakened immune system. This therapy requires patience: antibiotics have to be taken for weeks or months to be effective.

By the way: Cats can also be treated with antibiotics in individual cases. However, this is usually not necessary.

How can you prevent cat scratch disease?

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For cat lovers, good flea prophylaxis is the best prevention against cat-scratch disease. Since the bacterium gets into the cat’s body via fleas, this is effective protection. This is why indoor cat owners are exposed to a lower risk than outdoor cat owners.

People with immunodeficiency should discuss with their doctor how high the risks associated with keeping cats are in their individual cases. Because other diseases can also be transmitted to humans through cats.