Giardia Lamblia

What sample is needed for Giardia Lamblia?

1. Make a saline wet smear from the loose stool.
2. Make a smear from the duodenal contents.
3. Make formalin-ethyl acetate concentrate of formed stool. Stain it with iodine.

• Giardia lamblia (Giardia duodenalis) causes Giardiasis or Lambliasis.

How will you define Giardia Lamblia?

• It is a flagellated protozoan and an important cause of diarrhea worldwide.
•  This protozoan lives in the duodenum and proximal jejunum.
• This is the most common parasite in the USA.

Discuss history of Giardia Lamblia?

1. Giardia lamblia was discovered in 1681 by Anton van Leeuwenhoek on examination of his stool.
2. Secretary Robert Hooke wrote the first description of giardia of the Royal Society of London.
3. Alfred Giard studied the flagellate from 1879 to 1881 and gave the name Giardia.
4. Giardia trophozoites resemble the older man with mustaches and eyes.
   1. Some referred to them as looking like a monkey’s face.

What is the epidemiology of Giardia Lamblia?

1. This disease is present throughout the world (Cosmopolitan).
2. This disease is more common in children from 6 to 10 years.
3. Giardia is highly infectious through contaminated foods and water.
   1. These cysts may spread through contaminated fruits and vegetables.
   2. These cysts are resistant to routine chlorination.
   3. Such water needs filtration and chemical treatment.
4. Giardia may be sexually transmitted through oro-anal sex.
5. This may spread through the water rodents.
6. The groups at high risk are:
   1. Children in the daycare facility.
   2. People are living with poor sanitation.
   3. Travelers are traveling to endemic areas.
   4. People who are engaged in homosexual practice.
7. In summary:
   1. It spreads through contaminated foods and water, sewage, flies, or food handlers and by hand to mouth.
8. Man is the natural host.
   1. More common in children 6 to  10 years of age.
   2. Rats may get a temporary infection.
9. There are outbreaks due to water-borne infections.
   1. Cysts are demonstrated in water in some outbreaks.

How will you classify Giardia Lamblia?

1. This flagellate parasite belongs to:
   1. Subphylum Mastigophora.
   2. The class is Zoomastigophora.

Giardia Lamblia: Classification of the flagellates

2. This spread through the oral-fecal route.
3. Diseases are spread by infected water and foods.

How will you describe a summary of the life cycle of Giardia lamblia:

Discuss the mature cyst of Giardia Lamblia?

1. It is ingested, passes through the stomach, and enters the small intestine.
2. In the stomach, acid stimulates the cyst to excyst in the duodenum.
3.  The mature cyst has 4 nuclei.
4. The size varies from 8 to 17 μm long and 6 to 10  μm wide.
5. The cyst is colorless and smooth; it is distinct from the interior.
6. The immature cyst has two nuclei and two median bodies.
7. Nuclei are seen in the iodine preparation or with a permanent stain.

8. In the duodenum, excystation takes place.
   1. This cyst releases the trophozoites, which mostly live in the small intestine.
      1. These trophozoites multiply roughly every 8 hours.
      2. In the small intestine, because of their sucking disc, they resist migration to the large intestine.
      3. They feed them by the suckling disc.
      4. They multiply in the small intestine.
      5. Trophozoites may enter the common bile duct and the gallbladder.
9. Then, entrapped trophozoites enter the colon. Here, encystment occurs.

How will you describe the trophozoites of Giardia Lamblia?

1. It measures  8 to 12 μm in length and 5 to 16 μm in width.
2. These are pear or teardrop in shape.
   1. Anteriorly, it is broad and round.
   2. Posteriorly, it is tapering.
   3. The dorsal surface is convex.
   4. It is a central karyosome.
   5. There are two axostyles.
3. These have falling leaf movements.
4. There are two ovoid nuclei.
   1. These are symmetrical and best seen on the stained smear.
5. There are four pairs of flagella.
6. There are two median bodies.

Giardia Lamblia trophozoite

7. There is encystation because of the unfavorable atmosphere in the large intestine.
8. Now, these cysts are released into the stool.
   1. The cysts are released in the feces, which can survive 3 months in the water.
   2. The trophozoites cannot survive outside and soon die.

Discuss the pathogenesis of the disease caused by Giardia Lamblia?

1. The attachment of the parasites to intestinal epithelial cells produces low-grade catarrhal inflammation.
2. Mechanical and the action of the toxin interfere with the absorption of vitamin A and fats.
3. There is weight loss.
4. Cysts pass unharmed through the stomach juice.
   1. Excystation occurs in the duodenum.
5. There was a study on the volunteers.
   1. Ingestion of 100 or more cysts leads to infection in all the volunteers.
   2. 10 to 25 cysts will infect 1/3 of the volunteers.
   3. 1 cyst will not cause infection.
6. Chlorination will not kill the parasite, but iodine can.

How will you discuss the clinical Presentation of Giardia Lamblia?

1. The patient may be asymptomatic.
2. The incubation period is  1 to 3 weeks when the patient develops signs and symptoms.
3. The patient may have mild to severe diarrhea with light-colored, fatty stool.
   1. This patient may have watery and occasionally foul-smelling diarrhea.
   2. This is due to irritation by the trophozoites.
   3. The stool is light-colored.
   4. The stool may be soft and greasy.
4. There may be abdominal pain, cramps, flatulence, and epigastric tenderness.
5. There is more gas and flatulence in these patients.
   1. This patient may develop abdominal cramps and bloat.
   2. There is nausea.
   3. There may be an epigastric tenderness.
   4. The patient may have anorexia.
6. In severe cases, steatorrhea is not uncommon and may lead to a picture of malabsorption syndrome.
7. Symptoms may be lost in 3 to 4 days or 1 to 3 weeks or may become chronic.

How will you discuss the Traveler’s diarrhea?

1. Mild diarrhea, abdominal cramps, and anorexia characterize it.
2. There may be weight loss.
3. Ultimately, there is a typical picture of malabsorption syndrome.
4. These symptoms may last for 2 to 6 weeks and, in some, last longer.

What are the Complications of Giardia Lamblia (Giardiasis)?

1. There may be a deficiency of fat-soluble vitamins.
2. There may be a deficiency of folic acid.
3. There is hypoproteinemia.
4. There may be hypogammaglobulinemia.
5. There are structural changes in the intestinal villi.

how will you make the laboratory Diagnosis of Giardia Lamblia? 

1. Stool examination: Multiple samples are tested to rule out giardiasis.
   1. By this method, positivity is 50% to 70%.
   2. Three samples are enough, and each sample at a 2-day interval is sufficient.
   3. When you check multiple slides, the first sample detects 75% of the cases.
2. Make a direct wet or saline smear from the stool and look for Giardia.
3. Trophozoites:
   1. The unstained smear shows the trophozoites with progressive falling leaf motility.
   2. It is pear-shaped with a posterior end.
   3. This unstained smear is suggestive of Giardia.
   4. In duodenal aspirate or biopsy, you may see trophozoites.
4. A stained smear is diagnostic and shows all parts of trophozoites.
   1. Nuclei are seen in the area of the sucking disc.
   2. Parabasal bodies are seen posterior to the sucking disc.
   3. There is a typical arrangement of axonemes.
5. Cysts:  These measure 8 to 14 μm by 7 to 10 μm.
   1. Giardia cysts may pass at 1, 2, 3, or even 7 to 8 days intervals.
   2. Unstained cysts are suggestive of Giardia.
   3. This is oval in shape.
   4. There are refractile threads in the cytoplasm.
6. Cyst-stained is diagnostic.
   1. There are four nuclei.
   2. There are four median bodies.
   3. There are numerous axonemes.
7. Duodenal aspiration of the biopsy may be done to diagnose it.
   1. Duodenal aspirated material detects 80% of the cases, more than stool positivity.
8. Serological test:
   1. Direct fluorescent antibody test.
   2. Detection of Giardia antigen by EIA has more sensitivity than stool examination.
9. Summary of the diagnosis:
   1. Identification of the cysts or trophozoites in the stool.
   2. Trophozoites can be found in the duodenal aspirate or biopsy.

How will you treat Giardia Lamblia?

1. The most commonly used drug is Metronidazole (Flagyl). 250 mg tablets three times a day for 5 days.
   1. Young children’s total daily  dose is:
      1. For those under 2 years of age, it is 125 mg.
      2. 2 to 4 years of age 250 mg.
      3. 4 to 8 years of age is 375 mg.
      4. 8 to 12 years of age is 500 mg.
2. Albendazole 400 mg daily for 5 days.
3. Mebendazole 200 mg three times a day for 5 days.
4. Another used drug is Tinidazole (Tindamax), which is a single dose.
5. Nitazoxanide (Alinia) is liquid and easy for children to swallow.

G. Lamblia looks like a human with two eyes

Giardia cyst is seen in the stool

How you can Control of the Giardiasis (Prevention)?

1. Prevent fecal-contaminated water and foods.
2. Safe sex.
3. Portable purification unit for travelers.
4. Educate the public on the transmission of the disease and methods to protect it. 
5. The double strength of iodine is needed to kill the giardia.

Questions and answers: