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GIARDIASIS What
are Giardia? Giardia
are sometimes confused with worms because they invade the gastrointestinal tract
and can cause diarrhoea. They are
not worms; instead, they are one-celled parasites classified as protozoa and
have been largely overlooked until recently. Most
dogs that are infected with Giardia do not have diarrhoea or any other signs of
illness. When the eggs (cysts) are
found in the faeces of a dog without diarrhoea, they are generally considered a
transient, insignificant finding. However,
in puppies and debilitated adult dogs, they may cause severe, watery diarrhoea
that may be fatal. In a recent survey in London approximately 15% of healthy
adult dogs and 30% of puppies were found to be infected. How
did my dog get Giardia? A
dog becomes infected with Giardia when it swallows the cyst stage of the
parasite. Once inside the dog's
intestine, the cyst goes through several stages of development.
Eventually, the dog is able to pass cysts in the faeces.
These cysts lie in the environment and can infect other dogs.
They may also be transmitted through drinking infected water. How
is giardiasis diagnosed? Giardiasis
is diagnosed by performing microscopic examination of a sample of faeces.
The cysts are minute and require special techniques for their detection.
Occasionally, the parasites may be seen on a direct smear of the faeces.
A blood test is also available for detection of antigens (cell proteins)
of Giardia in the blood. This test is probably more accurate than the faeces exam, but
it requires several days to get a result from the laboratory performing the
test. How
is giardiasis treated? The
typical drug used to kill Giardia is metronidazole, an antibiotic-type drug.
It is given for 5-7 days. Other
drugs are also used if diarrhoea and dehydration occur.
If metronidazole is not effective, others are available. Can
humans become infected with Giardia? Giardia
can also cause diarrhoea in humans and children are especially susceptible.
Therefore, environmental disinfection is important.
The use of chlorine bleach, approximately one cup in 250 ml in 5 litres)
of water, is effective if the surfaces and premises can be safely treated with
it. If in doubt, please contact us.
Other disinfectant agents are available. |