Giardia lamblia is also known as Lamblia intestinalis and Giardia duodenalis It is a flagellated parasite that colonizes and reproduces in the small intestine, causing giardiasis.

1. Giardia lamblia
By :Nandita Purohit
(M.Sc. Zoology)

2. synopsis
• Introduction
• History
• Life cycle
• Giardiasis
• Giardia in Pets
• Symptoms in Human
• Diagnosis
• Treatment

3. introduction
• Giardia lamblia is also known as Lamblia
intestinalis and Giardia duodenalis
• It is a flagellated parasite that colonizes
and reproduces in the small intestine,
causing giardiasis.
• It is found on surfaces or in soil, food, or
water that has been contaminated with
feces from infected people or animals.
• The parasite attaches to the epithelium by
a ventral adhesive disc, and reproduces via
binary fission.
• It is protected by an outer shell called a
cyst that allows it to survive outside the
body for long periods of time and makes it
somewhat tolerant to chlorine disinfection.

4. history
• The first likely description of Giardia was in 1681 by Antonie
van Leeuwenhoek who, in a letter to Robert Hooke, described
"animalcules" resembling Giardia trophozoites in his stool.
• The next known description of Giardia wasn't until 1859, when
Czech physician Vilém Lambl published a description of the
trophozoite stages he saw in the stool of a pediatric patient.
• Lambl termed the organism Cercomonas intestinalis.
• In 1888, Raphaël Blanchard renamed the parasite Lamblia
intestinalis in Lambl's honor.
• In 1915, Charles Stiles renamed the organism Giardia lamblia in
honor of both Lambl and Professor Alfred Mathieu Giard of
Paris.
• In 1921, Charles E. Simon published a detailed description of the
parasite's morphology.

5. Life cycle
• Giardia cysts can contaminate food, water, and
surfaces, and they can cause Giardiasis when
swallowed in this infective stage of their life cycle.
• Infection occurs when a person swallows cysts from
contaminated water, food, hands, surfaces, or objects.
• When cysts are swallowed, they pass through the
mouth, esophagus, and stomach into the small intestine.
• Here, each cyst releases two trophozoites through a
process called excystation.
• The trophozoites then feed off and absorb nutrients
from the infected person.

7. contd.
• Trophozoites multiply by splitting in two in a process called
longitudinal binary fission, remaining in the small intestine
attached to its inside lining.
• The trophozoites then move toward the colon and transform
back into cyst form through a process called encystation.
• The Giardia cyst is the stage found most commonly in
stool.
• Both Giardia cysts and trophozoites can be found in the
stool of someone who has giardiasis and may be observed
microscopically.
• Cysts are immediately infectious when passed in the stool
or shortly afterward, and the cysts can survive several
months in cold water or soil.

8. giardiasis
• Giardiasis is an infection in the small intestine, caused
by a microscopic parasite called Giardia lamblia.
• It spreads through contact with infected people.
• Pet dogs and cats also frequently contract giardia.
• One can also get giardiasis by eating contaminated food
or drinking contaminated water.
• Giardia can be found all over the world, according to
the Centers for Disease Control (CDC).
• However, it’s more common in overcrowded
developing countries that lack sanitary conditions and
water quality control.

10. Giardia in pets
• Dog and cat stool can contain Giardia germs and may
make them sick even when the pet appears healthy.
• Symptoms of Giardia infection in pets can include
diarrhea, gas, abdominal discomfort, nausea, and
vomiting.
• It is possible to be infected and have no signs or
symptoms of illness.
• The chances of people getting Giardia infection from
dogs or cats are low.
• The type of Giardia that infects humans is not usually
the same type that infects dogs and cats.

12. Symptoms of giardiasis in humans
• Symptoms typically develop 9–15 days after
exposure, but may occur as early as one day.
• Symptoms vary from none to severe diarrhea with
poor absorption of nutrients.
• It can result in weakness, loss of appetite,
stomach cramps, vomiting, bloating, excessive
gas, and burping.
• Symptoms generally begin by having 2 to 5 loose
stools per day, with progressively increasing
fatigue.

14. diagnosis
• One may have to submit one or more stool samples for
testing.
• A technician checks stool sample for giardia parasites.
• The patient might also submit more samples during
treatment.
• Doctors in some cases may also perform an enteroscopy.
• This procedure runs a flexible tube down the throat and
into the small intestine to examine your digestive tract and
take a tissue sample.
As Giardia lamblia is difficult to detect, this often leads to
a delay in diagnosis or misdiagnosis; several tests should
be conducted over a one-week period

15. treatment
• In most cases, giardiasis eventually clears up
on its own.
• The doctor might prescribe medication if the
infection is severe or prolonged.
• Most physicians recommend getting treated
with antiparasitic drugs, rather than leaving it
to heal on its own.
• Certain antibiotics are commonly used to treat
giardiasis:

17. contd.
• Metronidazole: antibiotic that can cause nausea
and leave a metallic taste in your mouth.
• Tinidazole: treats giardiasis in a single dose and is
as effective as metronidazole.
• Nitazoxanide: popular option for children because
it’s available in liquid form.
• Paromomycin: has a lower chance of causing
birth defects than other antibiotics, although
pregnant women should wait until after delivery
before taking any medication for giardiasis