Giardia is a protozoan parasite found all
over the world. It can affect
humans, most types of domesticated mammals, and birds. The parasite lives
in the intestinal tract and causes damage to the intestines.
Giardia can affect either sex, and any breed, although it is most
commonly seen in young animals and animals confined together in groups,
such as in kennels, shelters, and pet stores.
Although most cases of human Giardia point to other sources of
infection (person-to-person contact, or by contaminated water), animals do
harbor strains of Giardia that are infective to humans, and animal to
human transmission is theoretically possible.
Diarrhea is the most common sign of
infection. Some animals may
vomit in addition to the diarrhea. Weight
loss may occur secondary to the diarrhea.
In many instances, a cat may be infected with Giardia, but show no
clinical signs at all.
There are several ways to diagnose
Giardia infection. The most
common methods involve analysis of a fecal sample. Direct analysis of a fecal sample may lead to a quick
diagnosis. A fecal sample can
also be sent to a diagnostic laboratory for more sophisticated
immunology-based diagnostic tests.
Several drugs have been
used to treat Giardia infections. Antiparasitic
drugs are the mainstay of therapy, however, additional measures, such as
adding extra fiber to the diet, can help hasten recovery.
has been used extensively to treat Giardia in dogs and cats, as well as in
people. This drug has
reasonable efficacy, and has an added advantage of being effective against
other protozoans and some bacteria that might also be contributing to the
diarrhea. Side effects
involving the nervous system have been reported in some animals, although
this is uncommon. Fenbendazole
(Panacur) is a dewormer that kills common worms such as hookworms,
roundworms, and whipworms. When
given at the normal deworming dose, fenbendazole is also very effective in
treating Giardia. This drug
is very safe and fairly inexpensive.
Praziquantel/pyrantel/febantel (Drontal Plus) is a combination
dewormer that treats hookworms, roundworms, whipworms and tapeworms.
Recent studies show that it is effective against Giardia as well.
Cats with Giardia need to have their
prescribed medication administered faithfully.
High fiber diets often provide additional help
in controlling the
Decontamination of the
environment: in multiple pet households and in crowding situations
(kennels, shelters, pet stores), proper sanitation is key to prevent cross
contamination from one animal to another.
All fecal material needs to be removed from cages, runs, and yard.
Kennels need to be cleaned with proper disinfectants and let
totally dry before allowing animals into them.
Treatment: all animals
should be treated with appropriate medication before being introduced into
a multi-animal environment Shampooing:
bathing animals before introducing them into an uncontaminated environment
allows for removal of feces and infective cysts from the haircoat.
pet owners are to remove feces from their yard, keep cats indoors
if possible, and avoid allowing their dog to drink from streams and lakes.
A vaccine designed to aid in the prevention of disease caused by
Giardia has recently been marketed although its usefulness is
controversial and the American Association of Feline Practitioners
currently does not endorse its use.
There is considerable
controversy as to the potential for animals to spread Giardia to humans.
There is scant evidence linking human infections to dogs and cats.
Human cases of Giardia are usually caused by person-to-person
contact, or by drinking contaminated water.
Until these controversies are resolved, it is best to err on the
side of caution and treat all infected animals regardless of whether they
are experiencing symptoms or not. The
best way to detect infection is to have us regularly check a fecal sample
(at least twice a year).