Parasitology

Topics in this chapter

• Intestinal Protozoan Infections
• Blood and Tissue Protozoa
• Urogenital Protozoan Infections
• Nematode Parasitic Infections
• Cestode Parasitic Infections
• Trematode Parasitic Infections

Practice questions

1. Question 1Q-6A5832

   A 35-year-old immigrant from East Africa presents with terminal hematuria and dysuria. Cystoscopy reveals sandy patches and bladder mucosal ulceration. Biopsy of the bladder lesion is most likely to show which of the following parasite eggs?

   1. A.Egg with a prominent lateral spine
   2. B.Egg with a terminal spine
   3. C.Ooperculated egg with an abopercular knob
   4. D.Spherical egg with a thick striated shell containing a hexacanth embryo
   See the answer and solution
2. Question 2Q-A4B47D

   A 28-year-old man who recently returned from a backpacking trip in the Rocky Mountains presents with foul-smelling watery diarrhea, abdominal cramps, and excessive flatulence. Stool microscopy reveals flagellated pear-shaped trophozoites with a 'falling leaf' motility. Which of the following is the drug of choice for this condition?

   1. A.Metronidazole
   2. B.Albendazole
   3. C.Praziquantel
   4. D.Ivermectin
   See the answer and solution
3. Question 3Q-923C82

   A 45-year-old man with a history of alcoholism and cirrhosis presents with fever, right upper quadrant pain, and hepatomegaly. Ultrasound reveals a solitary, large, hypoechoic liver abscess. Aspiration yields 'anchovy-paste' fluid. Which of the following is the causative agent?

   1. A.Echinococcus granulosus
   2. B.Entamoeba histolytica
   3. C.Fasciola hepatica
   4. D.Clonorchis sinensis
   See the answer and solution
4. Question 4Q-332774

   A 6-year-old child presents with periorbital edema, myalgia, and marked peripheral eosinophilia after consuming undercooked pork. Which diagnostic modality is most specific during the acute phase of this infection?

   1. A.Stool microscopy for embryonated eggs
   2. B.Stoke's nutrient agar culture
   3. C.Muscle biopsy demonstrating encysted larvae
   4. D.Anal swab for Graham slide test
   See the answer and solution
5. Question 5Q-79BA0D

   A 32-year-old HIV-positive patient with a CD4 count of 50 cells/uL presents with severe headache and confusion. Brain MRI shows multiple ring-enhancing lesions with surrounding edema. He owns a pet cat. Which of the following is the definitive diagnostic method or primary finding for the most likely organism?

   1. A.Crescent-shaped tachyzoites seen in CSF smear or brain biopsy
   2. B.Trypomastigotes in peripheral blood smear
   3. C.Oocysts identified via modified acid-fast staining of stool
   4. D.Flask-shaped trophozoites with ingested RBCs
   See the answer and solution