Cat scratch disease

Other Names: Bartonellosis due to Bartonella henselae infection; Cat scratch fever, trench fever

Cat scratch disease (CSD) is a bacterial infection that primarily affects the lymph nodes. It is typically caused by the bacteria bartonella (Bartonella henselae). It is usually transmitted by being scratched or bitten by a cat, but rarely, no scratch or bite is involved.

Source of infection

• Cats can get infected with B. henselae from flea bites and flea dirt (droppings) getting into their wounds.
• By scratching and biting at the fleas, cats pick up the infected flea dirt under their nails and between their teeth.
• Cats can also become infected by fighting with other cats that are infected.
• The germ spreads to people when infected cats bite or scratch a person hard enough to break their skin.
• The germ can also spread when infected cats lick at wounds or scabs that you may have.
• The disease spreads when an infected cat licks a person’s open wound, or bites or scratches a person hard enough to break the surface of the skin.
• About three to 14 days after the skin is broken, a mild infection can occur at the site of the scratch or bite.

Cause

• CSD is caused by a bacterium called Bartonella henselae.
• About 40% of cats carry B. henselae at some time in their lives, although most cats with this infection show NO signs of illness.
• Kittens younger than 1 year are more likely to have B. henselae infection and to spread the germ to people.
• Kittens are also more likely to scratch and bite while they play and learn how to attack prey.

Signs and symptoms

• Most people with cat scratch disease have been bitten or scratched by a cat and develop a mild infection at the point of injury within about 3-14 days.
• The infected area may be warm and painful and may appear appear swollen and red with round, raised lesions.
• Lymph nodes, especially those around the head, neck, and upper limbs, become swollen.
• Additionally, a person with cat scratch disease may experience fever, headache, fatigue, achiness and discomfort (malaise), sore throat, enlarged spleen, and/or loss of appetite.
• In most cases, particularly in children and adolescents, having CSD once means that it cannot occur again.
• The recurrence of symptoms months after disease onset has been reported in a few adults with CSD.

Diagnosis

• The Warthin–Starry stain can be helpful to show the presence of B. henselae, but is often difficult to interpret.
• B. henselae is difficult to culture and can take 2–6 weeks to incubate.
• The best diagnostic method available is polymerase chain reaction, which has a sensitivity of 43-76% and a specificity (in one study) of 100%.
• Cat-scratch disease is characterized by granulomatous inflammation on histological examination of the lymph nodes.
• Under the microscope, the skin lesion demonstrates a circumscribed focus of necrosis, surrounded by histiocytes, often accompanied by multinucleated giant cells, lymphocytes, and eosinophils.
• The regional lymph nodes demonstrate follicular hyperplasia with central stellate necrosis with neutrophils, surrounded by palisading histiocytes (suppurative granulomas) and sinuses packed with monocytoid B cells, usually without perifollicular and intrafollicular epithelioid cells.
• This pattern, although typical, is only present in a minority of cases.

Treatment

Treatment in mild or moderate cases typically involves medicines or strategies to improve symptoms, such as using fever reducers, pain relievers, or local heat over the affected lymph node(s). In more severe or systemic cases, management may involve lymph node aspiration and/or antibiotics.

Prevention

• Cat scratch disease (CSD), Bartonella henselae
• Avoid rough play with cats, particularly strays and kittens, to prevent scratches.
• Treat cats for fleas using fipronil and other spot-on treatments. Check with your veterinarian.
• Use a flea collar or similar topical preventive on dogs (fipronil, methoprene, imidocloprid, or permethrin), especially if you have both cats and dogs in your household.
• Keep cats indoors and away from stray cats.
• People who have weakened immune systems should avoid owning cats less than one-year-old.
• Trench fever, Bartonella quintana
• Avoid exposure to human body lice. Body lice are typically associated with crowded living conditions and limited access to bathing and clean clothes.
• Do not share clothing, beds, bedding, and towels used by a person who might have body lice.
• Information about treating body lice is also available.
• Carrión’s disease, Bartonella bacilliformis
• Use insect repellents and wear long-sleeved shirts and long pants to avoid sand fly bites in areas where Carrión’s disease is common (South America).
• If possible, limit outdoor activities at dawn and dusk, when sand flies are most active.

External links

• CDC Cat scratch disease

NIH genetic and rare disease info

• NIH info on Cat scratch disease

Cat scratch disease is a rare disease.

Cat scratch disease Resources
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