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Cat Scratch Disease
(Bartonella henselae Infection)
Cat scratch disease (CSD) is a bacterial disease
caused by Bartonella henselae. It typically causes swelling
of the lymph nodes. It usually results from the scratch,
lick, or bite of a cat — more than 90% of people with the
illness have had some kind of contact with cats, often with
Bartonella henselae is found in all parts of the world. Cat
scratch disease occurs more often in the fall and winter.
In the United States, about 22,000 cases are diagnosed
annually, most of them in people under the age of 21. This
may be because children are more likely to play with cats
and be bitten or scratched.
Fleas spread the bacteria between cats, although currently
there is no evidence that fleas can transmit the disease to
humans. Once a cat is infected, the bacteria live in the
animal’s saliva. Bartonella henselae does not make a cat
sick, and kittens or cats may carry the bacteria for
months. Experts believe that almost half of all cats have a
Bartonella henselae infection at some time in their lives,
and cats less than 1 year old are more likely to be
What is cat
Most people with CSD have been bitten or scratched by a cat
and developed a mild infection at the point of injury.
Lymph nodes, especially those around the head, neck, and
upper limbs, become swollen. In most children and
adolescents, swollen lymph nodes are the main symptom of
the disease, and the illness often is mild. About one third
of people with cat scratch disease have other general
symptoms. These include fever (usually less than 101°
Fahrenheit or 38.3° Celsius), fatigue, loss of appetite,
headache, rash, sore throat, and an overall ill feeling.
Rare complications of B. henselae infection are bacillary
angiomatosis and Parinaud’s oculolandular syndrome.
Can my cat
transmit Bartonella henselae to
Sometimes cats can spread
B. henselae to people. Most people get CSD from cat bites
and scratches. Kittens are more likely to be infected and
to pass the bacterium to people. About 40% of cats carry B.
henselae at some time in their lives. Cats that carry B.
henselae do not show any signs of illness; therefore, you
cannot tell which cats can spread the disease to you.
People with immunocompromised conditions, such as those
undergoing immunosuppressive treatments for cancer, organ
transplant patients, and people with HIV/AIDS, are more
likely than others to have complications of CSD. Although
B. henselae has been found in fleas, so far there is no
evidence that a bite from an infected flea can give you
Cat scratch disease is not contagious from person to
Doctors usually diagnose cat scratch disease based on a
child’s history of exposure to a cat or kitten and a
physical examination. During the exam, a doctor will look
for signs of a cat scratch or bite and swollen lymph nodes.
In some cases, doctors use laboratory tests to help make
the diagnosis, including:
• skin tests, blood tests, and cultures to rule out other
causes of swollen lymph nodes
• a blood test that is positive for cat scratch disease
• a microscopic examination of a removed lymph node that
shows signs of cat scratch disease
Most cases of cat scratch disease resolve without any
treatment at all. Rarely, a swollen lymph node becomes so
large and painful that the doctor may recommend removing
fluid from the node with a needle and syringe. Antibiotics
can be used to treat the disease. If your child’s doctor
has prescribed antibiotics, give the medication to your
child on schedule for as many days as the doctor has
• Home Treatment
A child who has cat scratch disease does not need to be
isolated from other family members. Bed rest is not
necessary, but it may help if your child tires easily. If
your child feels like playing, encourage quiet play while
being careful to avoid injuring swollen lymph nodes. To
ease the soreness of these nodes, try warm, moist
compresses or give your child nonprescription medicines
like acetaminophen (such as Tylenol) or ibuprofen (such as
Advil or Motrin).
How can I
reduce my risk of getting cat scratch disease from my
• Avoid “rough play”
with cats, especially kittens. This includes any activity
that may lead to cat scratches and bites.
• Wash cat bites and scratches immediately and thoroughly
with running water and soap.
• Do not allow cats to lick open wounds that you may have.
• Control fleas.
• If you develop an infection (with pus and pronounced
swelling) where you were scratched or bitten by a cat or
develop symptoms, including fever, headache, swollen lymph
nodes, and fatigue, contact your physician.