CAT-SCRATCH FEVER
Cat-scratch fever, also known as cat-scratch disease (CSD),
is a disease of humans caused by a pleomorphic gram negative
bacteria. The bacteria is difficult to culture requiring
special culture conditions. The organism is stained by War-thin-Starry
silver stain and not by Gram stain. The organism can be
detected in biopsy or needle aspirate material from affected
tis.sues early in the disease. Because of the difficulty
in culturing the organism, diagnosis is based on 1) a history
of exposure to a cat, 2) illness characterized by regionallymphadenitis,
3) other causes of 1ymphadenopathy having been excluded,
4) characteristic histopathology of a lymph node, 5) the
presence of silver staining bacteria in biopsy material,
and depending on availability, 6) a positive skin test with
Hanger-Rose an-ti gen.
Cat scratch disease primarily affects children between
the ages of 2-12 and is reported most often in the fall
and winter months. The role of the cat is unknown but
it is suspected the organism is a commensal of the mouth,
skin, or picked up on the paws from the environment. The
organism causes no signs of illness in cats and is most
often associated with cats less than one year of age. Infection
by the CSD organism occurs commonly from a scratch, puncture
wound, or by the cat licking abraded skin. Soon after the
patient is scratched a red area develops which develops
into a blister. The blister ruptures, encrusts, and forms
a papule up to 1 cm in diameter which lasts for several
weeks. The organism is present in the papule. Regional1ymphadenopathy
develops 2-3 weeks after the initial exposure and glands
become painful. Most commonly, lymph nodes of the head,
neck axillary and inguinal areas are affected. In some
cases lymph nodes are abscessed. Usually 1ymphadenopathy
resolves in 2-4 months although it may last for up to 2
years. In a low number of patients conjunctival entry of
the organism (probably caused by wiping the organism across
the eyebrow by the hand) results in a soft granuloma or
polyp developing on the eyelid. This is referred to as Parinaud'soculog1andu1arsyndrome
.
The CSD organism is present in healthy cats and is not
highly infectious for all members of a household. Therefore,
it 1s not necessary to remove the cat from the fam-ily.
Prevention of CSD can be achieved by declawing the cat,
prompt washing of any scratches or wounds acquired while
handling a cat, not allowing a cat to lick open wounds
on a human, and washing hands well after handling a cat.
Antibiotics do not appear to shorten the course of the disease
or to prevent abscessation of lymph nodes. Suspected cases
should be referred to a family physician for proper diagnosis
and medical attention.
Terry L.Bowersock,DVM,PhD Chief of Microbiology
|