Pathogenesis of Giardia

A large number of trophozoites are attached to the bowel wall with the help of sucking discs that are present on the ventral surface of giardia lamblia and cause irritation. Low-grade inflammation of duodenal or jejunal mucosa is associated with crypt hypertrophy as well as atrophy and epithelial cell damage leading to acute or chronic diarrhoea.

Mode of Transmission

• Man is the main reservoir of Giardia.
• Infection is acquired due to:
  • Consumption of infected food or water is the cause of infection.
  • Spread from person to person as a result of unsanitary conditions in nursing homes, daycare centres, and mental asylums
  • Oral-genital and oral-anal sex as a means of sexual transmission.
• Giardiasis is more common in immunocompromised people, such as AIDS patients and those suffering from protein-energy deficiency.

Symptoms of Giardiasis 

The symptoms of Giardiasis include:

• Abdominal pain, cramp, dysentery.
• Rarely blood and mucus in stool.
• Chronic symptoms- malabsorption of B12, lactose intolerance, etc.

Diagnosis of Giardiasis 

The diagnosis of Giardiasis occurs by:

• The usual procedure for diagnosing giardiasis involves looking for cysts or trophozoites in stool samples. Since cyst excretion occurs sporadically, it is necessary to get numerous stool samples (at least three samples taken on different days) to exclude giardiasis.
• Giardia antigen tests have strong sensitivity (85 to 98%) and specificity (90 to 100%) and can be run on stool samples. These come in the form of immunoassays, such as fast tests (immunochromatographic tests) or ELISA (enzyme-linked immunosorbent assays).
• Although PCR may be a more sensitive method than microscopy or immunoassays for detecting Giardia-specific genes, most clinical laboratories do not regularly offer this service.

Treatment of Giardiasis 

Treatment options are:

• Fluids and rehydration for supportive therapy.
• In some cases, giardiasis goes away on its own without medication.
• If symptoms are severe or persistent, medication may be prescribed by a doctor.

Prevention of Giardiasis 

The preventions are:

• Frequent and thorough handwashing is essential, especially after using the toilet, changing diapers, and before preparing food.
• When outdoors, filter or boil drinking water from untreated sources like streams or lakes.
• Avoid swallowing pool, lake, or stream water while swimming.
• If traveling to areas with high giardia risk, consider bottled water for drinking and avoid using tap water for brushing your teeth.
• Practice safe sex, including condom use, to prevent transmission.
• Thoroughly clean and disinfect surfaces that may be contaminated with feces, especially in childcare settings.

Note:

Sometimes G.lambilia can also localizes in the biliary tract to causes cholecystitis and jaundice.

The Giardia life cycle starts in contaminated water or food, where cysts are ingested and then transform into trophozoites in the host’s intestines. Understanding Giardia life cycle stages and transmission helps in implementing effective prevention strategies and minimizing the spread of this parasitic infection.

In this article, we will cover in detail the life cycle of Giardia and its diagram.