29 Questions
Which type of parasites move by cilia?
Ciliates
What is the main characteristic of roundworms (Nematodes)?
Elongated, cylindrical, unsegmented
Which type of parasite has a tape-like, segmented body?
Cestodes
What is the mnemonic for remembering the body shape of trematodes and cestodes?
'Cestodes = cm = tape'
Which protozoan parasite is capable of causing sporadic or epidemic diarrheal illness?
Giardia lamblia
What is an important cause of waterborne and foodborne disease, daycare center outbreaks, and illness in international travelers?
Giardia lamblia
What is the mode of movement for Giardia lamblia?
Move by flagella
Which of the following is the infectious and diagnostic stage of Entamoeba histolytica?
Cyst
Which of the following parasites is known to cause liver abscess as a complication?
Entamoeba histolytica
A patient presented with bloody diarrhea with mucus. Which parasite could be responsible for this clinical manifestation?
Entamoeba histolytica
What is the complication of chronic giardiasis in children?
Stunted growth
Which species of Entamoeba is pathogenic?
Histolytica
How is cryptosporidium transmitted?
Fecal-oral
Which of the following is a good specimen for diagnosis of giardiasis?
Duodenal aspirate
Where does excystation take place for Entamoeba histolytica?
Small intestine
What is the drug of choice for amoebic dysentery?
Metronidazole
Which stage of Giardia is responsible for causing the disease by attaching to the mucosal surface and damaging the duodenal epithelium?
Trophozoites
How do Giardia cysts survive in the stomach to pass into the duodenum?
By forming a protective shell
What is the drug of choice for treating giardiasis?
Metronidazole
Which organ can be affected by extra-intestinal infections in amebiasis?
Liver
How is amebiasis primarily transmitted?
Contaminated water or food
What is a characteristic of Entamoeba histolytica cysts in the environment?
They can survive for long periods
How do Giardia and Entamoeba differ in their life cycle?
Giardia has a complex life cycle with cysts and trophozoites, while Entamoeba has a simple life cycle.
What are the clinical manifestations of symptomatic intestinal infections caused by Entamoeba histolytica?
Abdominal pain, bloody diarrhea, and bloody/mucous stools
How is intestinal amoebiasis diagnosed?
Stool examination revealing ingested RBCs, and serology or molecular testing
What are the symptoms of amebic liver abscess caused by Entamoeba histolytica?
Fever, right upper abdominal pain, hepatomegaly, and a well-defined mass on CT scan
How is cryptosporidiosis diagnosed?
Microscopy and Ag detection in stools, and in stool oocysts using a modified acid-fast stain or PCR
How is extra-intestinal amoebiasis diagnosed?
Serology, surgical aspirate, and radiological examination
What is the most effective way to prevent cryptosporidiosis?
Hygiene
Study Notes
- Entamoeba Histolytica causes both asymptomatic and symptomatic intestinal infections, including amebic dysentery.
- Clinical manifestations of symptomatic intestinal infections range from mild diarrhea to severe amebic dysentery, with abdominal pain, bloody diarrhea, and bloody/mucous stools.
- Intestinal amoebiasis: Trophozoites have the ability to hydrolyze host tissues and ingest blood cells, causing diarrhea with blood, mucus, and sometimes tenesmus, and may cause serious complications such as intestinal perforation and amebic liver abscess.
- Extraintestinal amoebiasis: Complications include amebic liver abscess, with symptoms such as fever, right upper abdominal pain, hepatomegaly, and a well-defined mass on CT scan.
- Intestinal perforation: A flask-shaped ulcer and inflammatory response in the large intestine can lead to peritonitis and death.
- Diagnosis: Intestinal amoebiasis can be diagnosed through stool examination, which may reveal ingested RBCs, and serology or molecular testing. Extra-intestinal amoebiasis is diagnosed through serology, surgical aspirate, and radiological examination.
- Treatment: Intestinal amoebiasis can be treated with diloxanide furoate for asymptomatic cases, or metronidazole for symptomatic cases. Extra-intestinal amoebiasis is treated with metronidazole.
- Cryptosporidium Parvum: An intracellular protozoan parasite that causes self-limited diarrhea in immunocompetent individuals but can cause severe debilitating diarrhea, weight loss, and malabsorption in immunocompromised patients.
- Cryptosporidiosis: Diagnosis is based on microscopy and Ag detection in stools, and in stool oocysts using a modified acid-fast stain or PCR.
- Prevention and treatment: Hygiene is the most effective way to prevent cryptosporidiosis. In AIDS patients, paromomycin can be used for treatment.
- Comparison with Giardia: Both parasites can cause intestinal infection and diarrhea, but Entamoeba histolytica is capable of causing extraintestinal complications and more severe symptoms, while Cryptosporidium parvum is primarily an opportunistic infection in immunocompromised patients.
Test your knowledge on distinguishing between Entamoeba Histolytica and Entamoeba Dispar infections based on their clinical picture and lab examination. Learn about the outcomes and clinical manifestations of these two similar but distinct parasitic infections.
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