38 Questions
What is characteristic of the scolex of Taenia saginata?
Lacks rostellar hooks
How many proglottids does Taenia saginata have?
1000-2000
What is characteristic of Entamoeba histolytica?
Motility in one direction, progressive
What is characteristic of Entamoeba coli?
Motility in several directions, sluggish
What is characteristic of the trophozoite of Entamoeba histolytica?
One pseudopod, finger-like
What is characteristic of the cyst of Entamoeba histolytica?
Chromatoidal bars present
What is characteristic of the nucleus of Entamoeba histolytica?
Consists of thin nuclear membrane with uniformly sized chromatin granules
What is characteristic of the nucleus of Entamoeba coli?
Consists of thicker nuclear membrane with variously sized chromatin granules
What is the result of the combination of macro- and microgametocytes in the Anopheles mosquito?
Zygote
What is the characteristic periodic fever pattern of P.falciparum?
Every 36 hours
Which of the following is a complication of P.falciparum infection?
All of the above
What is the purpose of thick blood film in malaria diagnosis?
To screen for malaria
What is the function of hypnozoites in malaria?
To release merozoites
Which genetic disorder is resistant to malaria?
Sickle cell disease
What is the term for a mixed infection of P.vivax and P.falciparum?
Mixed infection
What is the name of the stain used in the diagnosis of malaria?
Giemsa stain
What is a common cause of congenital infection?
Toxoplasma gondii
What is the characteristic of the trophozoite stage of Dientamoeba fragilis?
It has two nuclei
What is the name of the test used to diagnose Toxoplasma gondii?
Sabin-Feldman dye test
Which of the following is a disease caused by Toxoplasma gondii?
Gastroenteritis with diarrhea
What is the name of the form of Toxoplasma gondii that is actively dividing?
Tachyzoite
What is the intermediate host of Diphyllobothrium latum?
Copepods
What is the characteristic of the vacuolated form of Blastocystis hominis?
It has a large central vacuole
What is the mode of transmission of Dientamoeba fragilis?
Through the transmission of Enterobius vermicularis eggs
What is the common name of the insect that is the vector of urban dengue?
Tiger mosquito
What type of filariasis is Mansonia bonneae associated with?
Brugian filariasis
What is the purpose of examining thick blood films in laboratory methods?
Screening for malaria
What is the name of the cockroach that lays about 50 egg capsules?
Periplaneta americana
What type of larvae is associated with the disease Myiasis?
Dipterous larvae
What is the common name of Pthirus pubis?
Crab louse
What is the name of the mosquito that is a vector of rural dengue?
Aedes albopictus
What is the name of the fly that has a 'chess-board appearance'?
Sarcophaga
What is the Leishman-Donovan body also known as?
Amastigote
What is the agent of Old World cutaneous leishmaniasis?
Leishmania tropica
Where is the nucleus located in the Epimastigote form?
Near nucleus
What is the vector of Leishmania?
Phlebotomus
What is the pathology of Leishmania tropica?
Localized cutaneous infection
What is the habitat of Leishmania braziliensis?
Mucocutaneous junctions
Study Notes
Stool Examination
- Taenia saginata: no scolex, length up to 25m, 1000-2000 proglottids
- Taenia solium: scolex with rostellum and 2 rows of hooklets, length up to 7m
Amoebas
-
Entamoeba:
- Trophozoite: unidirectional motility, 1 pseudopod, endoplasm with RBC but no bacteria
- Cyst: peripheral chromatin, chromatoidal bars
-
Endolimax/Iodamoeba:
- No peripheral chromatin, no chromatoidal bars
Hemoflagellates
- Include trypanosomes and leishmanias
- Infect blood, lymph nodes, muscles, and RES
- Amastigote: Leishman-Donovan body, leishmanial form
- Promastigote: leptomonal form, near nucleus
- Epimastigote: crithidial form, near nucleus
- Trypomastigote: trypanosomal form, posterior to nucleus
Leishmania
- Leishmania tropica: agent of old world cutaneous leishmaniasis, habitat in endothelial cells and monocytes, vector Phlebotomus or Lutzomyia
- Leishmania braziliensis: agent of American mucocutaneous leishmaniasis, habitat in mucocutaneous junctions, vector Phlebotomus or Lutzomyia
Malaria
- Symptoms and Pathology: recurrent chills and fever, anemia, splenomegaly, joint pain
- P. falciparum: malignant tertian malaria, cerebral malaria, blackwater fever
- P. ovale: benign tertian malaria
- P. vivax: benign tertian malaria, relapse due to hypnozoites
- P. malariae: quartan malaria
- Lab Diagnosis: examination of blood film, thick film for screening, thin film for species identification
Toxoplasma gondii
- Characteristics: common cause of congenital infection
- DH: cat, oocyst in cat feces may infect man
- IH: man, bradyzoite = inactive form, tachyzoite = actively dividing
- Lab Diagnosis: Sabin-Feldman dye test
Other Intestinal Protozoans
- Blastocystis hominis: vacuolated form, large central vacuole
- Dientamoeba fragilis: former amoeba, now classified as flagellate, trophozoite stage only, 2 nuclei (“Binucleated trophozoite”)
Arthropods
- Copepods (Cyclops): IH of D. latum, D. medinensis, and Gnathostoma spinigerum
- Pthirus pubis: crab louse, agent of “crabs”
- Myiasis: invasion of mammalian tissues by dipterous larvae
- Cantharidin: volatile vessicating substance produced by beetles of the family Meloidae
- Various mosquitoes and flies, including vectors of diseases such as dengue, Japanese encephalitis, and filariasis
Compare and contrast the characteristics of Taenia saginata and Taenia solium, including scolex, length, and proglottids.
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