Gardia intestinalis

Question 1

What is the classification of Gardia intestinalis?

Answer 1

obligated protozoa (cannot survive without host) category: flagellates

Question 2

Which types of G. intestinalis cause infection

Answer 2

A - symptomatic

B- asymptomatic

Question 3

How is G. intestinalis transmitted?

Answer 3

• via the fecal-oral route
• direct: person to person (rare)
• indirect: contaminated food, water, surfaces, or objects with cysts

Question 4

How is G. intestinalis constructed and what are the functions of these elements

Answer 4

• multiple flagellates (for movement)

- central adhesive disk (for attachment to epithelial cells)

Question 5

What is the life cycle of G. intestinalis?

Answer 5

1. Cysts get swallowed
2. Cysts pass through the esophagus and stomach into the small intestine
3. In the small intestine each cyst releases 2 trophozoites (excystation)
4. The Gardia cysts feeds of and absorbs nutrients from te host
5. The throphozoites multiply by splitting in 2 through binary fussion (asexual reproduction) - This happens still in the small intestine (they can be free or attach to the wall of the small intestine)
6. Trophozoites move towards the colon an transform back to the cyst form (encystation) - most common stage found in stool
7. Cysts get excreted through stool
8. Cysts are immediately infectious once they leave the body and can survivie for several months in soil and cold water (humid environment - 0-10 degrees)

Question 6

What is the infective form of G. intestinalis?

Answer 6

Cysts

- very resistant (contributes to the transmission)

Question 7

What type of life cycle has G. intestinalis?

Answer 7

Direct lifecycle

Question 8

What type of host is the human for G. intestinalis?

Answer 8

Intermediate host, as G. intestinalis only asexually reproduces

Question 9

What is the incubation time for G. intestinalis?

Answer 9

1 to 14 days (avarage 7 days) and usually lasts 1-3 weeks. A host is infectious until there are no more cysts secreted or present in the feces.

Question 10

What are the symptoms of G. intestinalis?

Answer 10

Asymptomatic in most cases (50-75%)

Symptoms: diarrhea, abdominal pain, bloating, nausea, vomiting and weight/ musle loss - fever only in the early stage of the infection

Chronic infection - recurrent symptoms and malbsorption and debilitation

Question 11

Where is G. intestinalis endemic?

Answer 11

Worldwide, more prevelent in warm climates and in children. More prevelent in developing countries due to less hygiene. Seasonal in the Netherlands in aug/ sept and okt.

Question 12

How is G. intestinalis diagnosed?

Answer 12

Triple feces test - 3x because not in every stool sample is G. intestinalis

• golden standard
• checks for cysts/ thropozoites - cysts are more frequently found (Trophozoites only located in fresh stool and are correlated with symptomatic infection)

Elisa

• Test for present antigen
• Uses feces

Biobsy of small intestine tissue

• biopsy, only done if other tests can’t detect but there is a strong suspicion of infection ]
• G. intestinalis not in blood
• only done if other methods are negative, but there is a high suspicion of G. intestinalis

PCR (real time & multiplex)

• multiplex can be used to test for other parasites at the same time
• when parasitemia is low the test is negative