26 Questions
Which kingdom and subkingdom do human parasites such as Entamoeba histolytica belong to?
Protista, Protozoa
What is the main method of locomotion and feeding for Sarcodina (Amoebae)?
Pseudopodia
What is the size range of the trophozoite form of Entamoeba histolytica?
10-60 µm
Where do trophozoites of Entamoeba histolytica reside?
Mucosa and submucosa of large intestine
How does man acquire infection with Entamoeba histolytica?
By ingestion of mature quadrinucleate cysts in faecally contaminated food or water
What happens to trophozoites if they are passed in diarrhoeal stools?
They are rapidly destroyed once outside the body
What is the term used for the process of liberating a single tetranucleate amoeba from the cyst wall in the small intestine?
Excystation
Which species is morphologically indistinguishable from E. histolytica?
E. dispar
What causes destruction and necrosis of tissue and produces flask-shaped ulcers during growth?
Proteolytic enzyme secreted by E. histolytica
What is the term used for the process in which chromatin materials are concentrated into bars in the cytoplasm of the cyst?
Encystation
What is the term used for the fulminant brain infection caused by N. fowleri?
Naegleriasis
What type of infection may be acquired by inhalation of dust containing infective forms of N. fowleri?
Naegleriasis
What method is used for diagnosing E. histolytica by identifying cysts and trophozoites in the stool?
Microscopic identification
What type of cells are ingested by E. histolytica, allowing it to be morphologically distinguished?
Red blood cells
What is the drug of choice for asymptomatic infections of E. histolytica?
Paromomycin
What is used to differentiate between E. histolytica and E. dispar?
Molecular methods
What does Entamoeba dispar cause in individuals?
Asymptomatic infections
What may be an indication for surgical intervention in cases of amoebiasis?
Treatment failure with metronidazole
What is the route of invasion for the amoeboid forms causing primary amoebic meningoencephalitis (PAM)?
Invasion through the nasal mucosa and olfactory nerves to the brain
What are the common initial symptoms of primary amoebic meningoencephalitis (PAM)?
Severe frontal headache, fever, anorexia, nausea, vomiting
How long does it usually take for primary amoebic meningoencephalitis (PAM) to result in death after the onset of symptoms?
72 hours
What is the characteristic method for laboratory diagnosis of primary amoebic meningoencephalitis (PAM)?
Microscopy of cerebrospinal fluid (CSF)
Which type of vector is a housefly in the case of Entamoeba transmission?
Mechanical vector
What is the main function of a vector in the transmission of infections?
To act as a transport host, helping the pathogen to complete its life cycle
What is the role of a reservoir host in the context of infectious diseases?
To harbor the pathogen indefinitely with no ill effects
What distinguishes a biological vector from a mechanical vector?
Biological vectors transfer parasites between hosts but are not essential in the parasite's life cycle
Test your knowledge of protozoa classification with this quiz. Learn about the phyla Sarcomastigophora, Apicomplexa, Ciliophora, and Microspora, and their subphyla. Explore the diverse world of single-celled animals and their classification under the kingdom Protista.
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