Giardiasis - Giardia Lamblia (Giardia intestinalis, Giardia duodenalis) infection

Summary

This video discusses giardiasis, a common infection caused by the protozoan Giardia lamblia, transmitted via the fecal-oral route. The infection often leads to gastrointestinal symptoms such as diarrhea, abdominal cramps, bloating, vomiting, and weight loss, though 50% of cases are asymptomatic. The video explains Giardia's life cycle, pathophysiology, and how the parasite evades the immune system. It also covers diagnosis methods like stool analysis and PCR, and treatment options, including antimicrobial therapy and supportive care. Preventive measures like proper water treatment, hygiene, and food preparation are emphasized.

Takeaways

• 🦠 Giardiasis is a common infection caused by the protozoan Giardia lamblia, also known as Giardia duodenalis or Giardia intestinalis.
• 🚰 Transmission occurs via the fecal-oral route, often in areas with poor sanitation and limited water treatment.
• 🤢 Symptoms include diarrhea, abdominal cramps, greasy stools, bloating, vomiting, and weight loss, although 50% of infections are asymptomatic.
• 🌍 Giardiasis affects 200 to 300 million people annually, especially in regions with poor sanitation.
• 👶 Risk factors include being a child, working with children, lack of safe drinking water, unprotected anal sex, living in endemic areas, being a traveler, and immunocompromised individuals.
• 🔄 Giardia exists in two forms: cysts (infectious) and trophozoites (active form). The cysts are ingested and transform into trophozoites in the small intestine.
• 🧬 The trophozoites attach to the mucosal surface of the intestine, while non-attached ones revert to cysts, which are then excreted in stool.
• ❓ The pathogenesis of giardiasis involves malabsorption and diarrhea due to disruption of gut microbes, depletion of nitric oxide, and damage to the intestinal microvilli.
• 🧫 Diagnosis is through stool analysis, enzyme immunoassay, or stool PCR to detect Giardia antigens.
• 💊 Treatment includes antimicrobial therapy (metronidazole) and supportive care with fluid and electrolyte replacement, even for asymptomatic individuals to prevent transmission.

Q & A

What is giardiasis and what causes it?

Giardiasis is a common parasitic infection caused by the protozoan Giardia lamblia, also known as Giardia duodenalis or Giardia intestinalis.

How is giardiasis transmitted?

Giardiasis is primarily transmitted through the fecal-oral route, often by consuming contaminated food or water, or through direct contact with infected fecal matter.

What are the common symptoms of giardiasis?

Symptoms of giardiasis include diarrhea, abdominal cramps, greasy stools, bloating, vomiting, weight loss, and fatigue. However, about 50% of infections are asymptomatic.

Who is at higher risk of contracting giardiasis?

High-risk groups include children, individuals working with children, people without access to safe drinking water, those practicing unprotected anal sex, travelers to endemic areas, and immunocompromised individuals.

What are the two forms of Giardia in its life cycle?

Giardia exists in two forms: cysts, which are the infectious form, and trophozoites, which are the active, reproducing form in the small intestine.

How does the Giardia parasite cause damage to the intestines?

Giardia impairs the structure and function of intestinal tissue, leading to malabsorption and diarrhea. This occurs through disruption of the gut microbiome, depletion of nitric oxide, shortening of intestinal microvilli, and induction of inflammation.

What are the common routes of transmission for Giardia?

Giardia can be transmitted through waterborne, foodborne, or direct fecal-oral routes, often due to ingestion of contaminated food or water.

How is giardiasis diagnosed?

Giardiasis is diagnosed through stool analysis for cysts or trophozoites, enzyme immunoassays for Giardia antigens, stool PCR, and sometimes gastroscopy to confirm trophozoites in duodenal fluid.

What treatments are available for giardiasis?

Treatment includes antimicrobial therapy such as metronidazole, supportive care with fluid and electrolyte replacement, and treatment of asymptomatic individuals to prevent transmission.

What are the possible complications of giardiasis?

Complications include dehydration, persistent symptoms, malnutrition, failure to thrive in children, lactose intolerance, and rarely, reactive arthritis or irritable bowel syndrome.