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Overview
Cryptosporidiosis
is a disease caused by the protozoan parasite Cryptosporidium.
The species of the organism that affects mammals most commonly is
Cryptosporidium parvum. A
number of mammalian species including rodents, cattle, dogs, cats, and
people can develop gastrointestinal tract disease due to infection with
the organism. The fact that
serum antibodies are detected in many species of animals, including cats,
suggests that exposure to the organism is fairly common.
The infective form of the organism is the oocyst.
These oocysts are spread via fecal contamination of food or
drinking water. The organism
is very infective. It only takes a few oocysts to cause disease in people.
Cryptosporidiosis
may be a primary disease, or it may be a secondary disease in people or
animals with weakened immune systems.
The risk of exposure increases in crowded or unsanitary conditions.
For example, cryptosporidial diarrhea is common among children in
daycare centers. In cats and
dogs, it is more commonly seen in young animals (less than 6 months old).
Typically,
cryptosporidiosis is a self-limiting disease in animals with competent
immune systems; many animals (cats in particular) will be infected but
show no clinical signs at all. Others
will have mild diarrhea, but recover uneventfully.
Even though young animals are more susceptible to becoming
infected, some young animal may show no clinical signs when infected.
People of all ages can get cryptosporidiosis, and it is commonly
seen in people who work with cattle.
It is frequently diagnosed in veterinary students after contact
with infected calves. The
signs in people are similar to those of animals:
acute onset of lethargy, abdominal cramps, and profuse watery
diarrhea. The illness
generally subsides without treatment, although persistent diarrhea and
dehydration occasionally develops. The
severity of the disease depends on the immune competence of the person,
although people with healthy immune systems can certainly contract the
illness, as demonstrated in 1993 when 400,000 people in Milwaukee
developed diarrhea as a result of contracting the organism via the public
water supply. Immunocompromised
people, such as those with HIV/AIDS , may suffer severe diarrhea that
never resolves, and may even prove fatal.
Diagnosis
fecal
examination – animals suspected of having cryptosporidiosis should
have a fecal sample carefully sent to a laboratory for special staining
and examination techniques.
serology
– detection of antibodies against the organism identifies animals
that have been exposed to the organism, but it does not necessarily
diagnose active infection.
intestinal
biopsy – intestinal biopsy often reveals the organism as well as the
damage that the organism may have caused to the intestinal tract.
Treatment
Although
more than 100 drugs have been screened, there are very few drugs available
to successfully treat cryptosporidiosis.
There are several treatment options:
no
treatment – infections in immunocompetent animals or persons are usually
self-limiting, and full recovery often occurs.
antibiotics
– many antibiotics have been used in an attempt to treat
cryptosporidiosis. Paromomycin,
tylosin, and azithromycin have all been shown to have reasonable efficacy
when treating the disorder.
high
fiber diet – feeding a high fiber diet in conjunction with antibiotic
therapy and supportive care may be beneficial in helping resolve the
diarrhea more quickly.
supportive
therapy – severe dehydration may require hospitalization and intravenous
fluid therapy for several days.
Optimal
treatment for your pet requires a combination of home and professional
veterinary care. Follow-up
can be critical, especially if your pet does not rapidly improve.
Administer
all prescribed medications as directed.
Alert your veterinarian if you are experiencing problems treating
your pet.
Owners
of infected animals need to be aware that their cat should be isolated
from people who are immunocompromised.
Updated
2/9/06 |
