Which of the following infestations lead to malabsorption: March 2011
Correct Answer: Giardia lamblia
Description: Ans. A: Giardia lamblia The stool in giardial infestation is voluminous, foul smelling and contains large amount of mucus and fat but no blood. This is due to malabsorption since the parasites are coated on the mucosa, thus absorption suffers Giardia lamblia/Giardia intestinalis/Lamblia intestinalis/Giardia duodenalis) It is a flagellated protozoan parasite that colonizes and reproduces in the small intestine, causing giardiasis. The giardia parasite attaches to the epithelium by a ventral adhesive disc, and reproduces binary fission. Giardiasis does not spread the bloodstream, nor does it spread to other pas of the gastro-intestinal tract, but remains confined to the lumen of the small intestine. Giardia trophozoites absorb their nutrients from the lumen of the small intestine, and are anaerobes. If the organism is split and stained, it has a very characteristic pattern that resembles a familiar "smilev face" symbol. Chief pathways of human infection include - Ingestion of untreated sewage - Contamination of natural waters also occurs in watersheds where intensive grazing occurs The life cycle begins with a noninfective cyst being excreted with the feces of an infected individual. The cyst is hardy, providing protection from various degrees of heat and cold, desiccation, and infection from other organisms. A distinguishing characteristic of the cyst is four nuclei and a retracted cytoplasm. Once ingested by a host, the trophozoite emerges to an active state of feeding and motility. After the feeding stage, the trophozoite undergoes asexual replication through longitudinal binary fission. The resulting trophozoites and cysts then pass through the digestive system in the faeces. While the trophozoites may be found in the faeces, only the cysts are capable of surviving outside of the host. Distinguishing features of the trophozoites are large karyosomes and lack of peripheral chromatin, giving the two nuclei a halo appearance. Cysts are distinguished by a retracted cytoplasm. This protozoan lacks mitochondriaColonization of the gut results in inflammation and villous atrophy, reducing the gut's absorptive capability. Symptoms of infection include (in order of frequency) diarrhea, malaise, excessive gas (often flatulence or a foul or sulphuric-tasting belch, which has been known to be so nauseating in taste that it can cause the infected person to vomit), steatorrhoea (pale, foul smelling, greasy stools), epigastric pain, bloating, nausea, diminished interest in food, possible (but rare) vomiting which is often violent, and weight loss. Pus, mucus and blood are occasionally present in the stool. It usually causes "explosive diarrhea" and while unpleasant, is not fatal. People with recurring Giardia infections, paicularly those with a lack ,of the Immunoglobulin A antibody, may develop chronic disease. It is a cause of vitamin B12 deficiency, this a result of the problems caused within the intestinal absorption system
Category:
Microbiology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now