Parasitology Access Medicine
Regarding Babesia microti, which one of the following is most accurate? A It infects macrophages, causing them to lyse. B Doxycycline is the drug of choice for babesiosis. C It is transmitted by the bite of Culex mosquitoes. D Seeing sporozoites within red cells supports the diagnosis of babesiosis. E Babesia microti causes disease primarily in the northeastern region of the United States.
E Babesia microti causes disease primarily in the northeastern region of the United States.
Can be treated with mebendazole or pyrantel pamoate A Giardia lamblia B Plasmodium vivax C Taenia saginata D Clonorchis sinensis E Enterobius vermicularis
E Enterobius vermicularis
Each of the following parasites is transmitted by mosquitoes EXCEPT: A Leishmania donovani B Wuchereria bancrofti C Plasmodium vivax D Plasmodium falciparum
A Leishmania donovani
A protozoan that infects red blood cells A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
B Plasmodium falciparum
Causes blackwater fever A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
B Plasmodium falciparum
Chloroquine-resistant strains occur A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
B Plasmodium falciparum
Produces "banana-shaped" gametocytes A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
B Plasmodium falciparum
Your patient is a 55-year-old man with fever and increasing fatigue during the past week. Today, he was so weak he "could barely stand up." He had been working in Cameroon and Chad for 2 months and returned 2 weeks ago. On examination, he was febrile to 40°C, hypotensive, and tachycardic. Pertinent lab work revealed anemia and thrombocytopenia. Blood smear revealed ring-shaped trophozoites within red blood cells. Of the following, which one is the most likely cause? A Leishmania donovani B Plasmodium falciparum C Toxoplasma gondii D Trypanosoma brucei E Trypanosoma cruzi
B Plasmodium falciparum
A protozoan transmitted by mosquito A Giardia lamblia B Plasmodium vivax C Taenia saginata D Clonorchis sinensis E Enterobius vermicularis
B Plasmodium vivax
Can be treated with chloroquine and primaquine A Giardia lamblia B Plasmodium vivax C Taenia saginata D Clonorchis sinensis E Enterobius vermicularis
B Plasmodium vivax
Causes fever, chills, and anemia A Giardia lamblia B Plasmodium vivax C Taenia saginata D Clonorchis sinensis E Enterobius vermicularis
B Plasmodium vivax
Causes filariasis A Dracunculus medinensis B Loa loa C Onchocerca volvulus D Wuchereria bancrofti E Toxocara canis
D Wuchereria bancrofti
Of the following drugs, which one is the MOST effective in nematode infections? A Albendazole B Chloroquine C Praziquantel D Primaquine E Stibogluconate
A Albendazole
You are a volunteer with Doctors Without Borders in sub-Saharan Africa. In certain villages, you detect anemia in a significant number of children. This is most likely due to infection with which one of the following? A Ancylostoma duodenale B Ascaris lumbricoides C Enterobius vermicularis D Trichinella spiralis E Wuchereria bancrofti
A Ancylostoma duodenale
Your patient is a 50-year-old man with a fever and shaking chills who had been vacationing 2 weeks ago on one of the islands off the coast of Massachusetts. Microscopic examination of a blood smear reveals ring-shaped trophozoites in tetrads within red blood cells. Of the following, which one is the most likely cause? A Babesia microti B Cryptosporidium parvum C Naegleria fowleri D Toxoplasma gondii E Trypanosoma cruzi
A Babesia microti
Your patient is a 30-year-old man with persistent watery diarrhea for 2 weeks. He is HIV antibody positive with a CD4 count of 10. Routine stool culture revealed no bacterial pathogen. Ova and parasite analysis revealed cysts that stained red in an acid-fast stain. Of the following, which one is the most likely cause of this infection? A Cryptosporidium hominis B Entamoeba histolytica C Giardia lamblia D Trichomonas vaginalis
A Cryptosporidium hominis
Acquired by drinking contaminated water A Dracunculus medinensis B Loa loa C Onchocerca volvulus D Wuchereria bancrofti E Toxocara canis
A Dracunculus medinensis
Treated by extracting worm from skin ulcer A Dracunculus medinensis B Loa loa C Onchocerca volvulus D Wuchereria bancrofti E Toxocara canis
A Dracunculus medinensis
A protozoan transmitted by the fecal-oral route A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
A Entamoeba histolytica
Causes bloody diarrhea and liver abscesses A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
A Entamoeba histolytica
Produces cysts with four nuclei A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
A Entamoeba histolytica
Regarding Entamoeba histolytica, which one of the following is most accurate? A Entamoeba histolytica causes "flask-shaped" ulcerations in the colon mucosa. B Domestic animals such as dogs and cats are the main reservoir of E. histolytica. C In the microscope, E. histolytica is recognized by having two sets of paired flagella. D Entamoeba histolytica infections are limited to the intestinal mucosa and do not spread to other organs. E The infection is typically acquired by the ingestion of the trophozoite in contaminated food and water.
A Entamoeba histolytica causes "flask-shaped" ulcerations in the colon mucosa.
A protozoan transmitted by the fecal-oral route A Giardia lamblia B Plasmodium vivax C Taenia saginata D Clonorchis sinensis E Enterobius vermicularis
A Giardia lamblia
Can be treated with metronidazole A Giardia lamblia B Plasmodium vivax C Taenia saginata D Clonorchis sinensis E Enterobius vermicularis
A Giardia lamblia
Causes diarrhea as the most prominent symptom A Giardia lamblia B Plasmodium vivax C Taenia saginata D Clonorchis sinensis E Enterobius vermicularis
A Giardia lamblia
Your patient is a 60-year-old man with abdominal pain, vomiting, and weight loss for the past 2 months. He has a history of asthma that requires 20 mg of prednisone daily to control. He lived most of his life in Cuba, moved to Spain 10 years ago, and has lived in this country for 1 year. Abdominal exam is normal, and radiographic studies are unrevealing. His white blood cell count is 10,900 with 16% eosinophils. Examination of the stool reveals rhabditiform larvae. Which one of the following is the best drug to treat the infection? A Ivermectin B Metronidazole C Nifurtimox D Pentamidine E Praziquantel
A Ivermectin
Your patient is a 25-year-old man with fever and weight loss for the past 3 weeks. He is a soldier in the U.S. Army who recently returned from a tour of duty in the Middle East. Physical exam was noncontributory. Laboratory tests revealed anemia and leukopenia. Multiple blood cultures for bacteria and fungi were negative, as was a test for the p24 antigen of HIV. Computed tomography (CT) scan of the abdomen revealed splenomegaly. A bone marrow biopsy was performed, and a stained sample revealed amastigotes within mononuclear cells. Of the following, which one is the most likely cause? A Leishmania donovani B Plasmodium falciparum C Toxoplasma gondii D Trypanosoma brucei E Trypanosoma cruzi
A Leishmania donovani
Each of the following parasites is transmitted by flies EXCEPT: A Schistosoma mansoni B Onchocerca volvulus C Trypanosoma gambiense D Loa loa
A Schistosoma mansoni
In malaria, the form of plasmodia that is transmitted from mosquito to human is the: A Sporozoite B Gametocyte C Merozoite D Hypnozoite
A Sporozoite
Laboratory diagnosis of a patient with a suspected liver abscess due to Entamoeba histolytica should include: A Stool examination and indirect hemagglutination test B Stool examination and blood smear C Indirect hemagglutination test and skin test D Xenodiagnosis and string test
A Stool examination and indirect hemagglutination test
Each of the following statements concerning Strongyloides stercoralis is correct EXCEPT: A Strongyloides stercoralis is acquired by ingestion of eggs. B Strongyloides stercoralis undergoes a free-living life cycle in soil. C Migrating larvae of S. stercoralis induce a marked eosinophilia. D Strongyloides stercoralis produces filariform larvae.
A Strongyloides stercoralis is acquired by ingestion of eggs.
Regarding Trichomonas vaginalis, which one of the following is most accurate? A The drug of choice for trichomoniasis is metronidazole. B Domestic animals, such as dogs and cats, are the principal reservoir of the organism. C Trichomonas vaginalis is typically acquired by contact with the cysts of the organism during sexual intercourse. D Laboratory diagnosis typically involves the detection of a greater than fourfold rise in the titer of IgA antibody. E The asymptomatic male sex partner of a woman with T. vaginalis infection should not be treated because asymptomatic men are rarely the source of the organism.
A The drug of choice for trichomoniasis is metronidazole.
Regarding Schistosoma mansoni, which one of the following statements is the most accurate? A The main site of S. mansoni in the human body is the mesenteric venules. B Schistosomiasis caused by S. mansoni has been eradicated from the Western hemisphere. C The laboratory diagnosis of S. mansoni depends on seeing eggs with a terminal spine in the stool. D Adult schistosomes are passed in the stool, and it is obligatory that they be ingested by freshwater snails to continue the life cycle. E Swimmer's itch occurs when S. mansoni eggs spread from the liver to the skin, where they induce a histamine-mediated immediate (type 1) hypersensitivity reaction.
A The main site of S. mansoni in the human body is the mesenteric venules.
Regarding plasmodium species, which one of the following is most accurate? A These organisms are transmitted by the bite of female Anopheles mosquitoes. B The bite of the vector injects merozoites into the bloodstream that then infect red blood cells. C Both male and female gametocytes are formed in the vector and are injected into the person at the time of the bite. D Hypnozoites are produced by P. falciparum and can cause relapses of malaria after the acute phase is over. E Malaria caused by P. vivax is characterized by a cerebral malaria and blackwater fever more often than malaria caused by the other three species.
A These organisms are transmitted by the bite of female Anopheles mosquitoes.
Regarding Acanthamoeba and Naegleria species, which one of the following is most accurate? A They are free-living amebas that live in warm fresh water. B Naegleria is a well-recognized cause of otitis media, primarily in children. C The drug of choice for infections caused by these organisms is chloroquine. D Their main clinical presentation is pneumonia acquired when water is aspirated into the lung.
A They are free-living amebas that live in warm fresh water.
Each of the following parasites is transmitted by eating inadequately cooked fish or seafood EXCEPT: A Diphyllobothrium latum B Ancylostoma duodenale C Paragonimus westermani D Clonorchis sinensis
B Ancylostoma duodenale
The larvae of certain nematodes migrate through the lung and cause pneumonitis characterized by cough or wheezing. Infection by which one of the following nematodes is most likely to cause this clinical picture? A Anisakis simplex B Ascaris lumbricoides C Enterobius vermicularis D Trichinella spiralis E Trichuris trichiura
B Ascaris lumbricoides
You are a volunteer with Doctors Without Borders in sub-Saharan Africa. In certain villages, you detect anemia in a significant number of children. You observe that some people are eating unwashed raw vegetables. Which one of the following organisms is most likely to cause infection in these people? A Ancylostoma duodenale B Ascaris lumbricoides C Enterobius vermicularis D Trichinella spiralis E Wuchereria bancrofti
B Ascaris lumbricoides
Which one of the following agents can be used to prevent malaria? A Mebendazole B Chloroquine C Inactivated vaccine D Praziquantel
B Chloroquine
Regarding Echinococcus granulosus, which one of the following is most accurate? A The drug of choice for E. granulosus infection is metronidazole. B Dogs are a required part of the life cycle of the causative organism. C E. granulosus is one of the longest tapeworms, sometimes measuring 10 ft in length. D E. granulosus larvae typically migrate to skeletal muscle, where they cause an abscess. E The main mode of transmission to humans is ingestion of eggs in food or water contaminated with human feces.
B Dogs are a required part of the life cycle of the causative organism.
Your patient is a 40-year-old man with occasional mild right upper abdominal discomfort but is otherwise well. On examination, his liver is enlarged. An MRI reveals a cystic mass in the liver. On questioning, he says that he was born and raised in rural Argentina on a sheep ranch and came to this country 10 years ago. Of the following, which one is the most likely cause? A Dipylidium latum B Echinococcus granulosus C Taenia saginata D Taenia solium
B Echinococcus granulosus
Your patient is a 30-year-old Peace Corps volunteer who has recently returned from Central America. She now has fever and right-upper-quadrant pain. She reports that she had bloody diarrhea 2 months ago. A computed tomography scan reveals a radiolucent area in the liver that is interpreted to be an abscess. Aspiration of material from the abscess was performed. Microscopic examination revealed motile, nonflagellated trophozoites with ameboid movement. Of the following, which one is the most likely cause of this infection? A Cryptosporidium hominis B Entamoeba histolytica C Giardia lamblia D Trichomonas vaginalis
B Entamoeba histolytica
Regarding P. jiroveci, which one of the following is most accurate? A The treatment of choice is a combination of penicillin G and an aminoglycoside. B Finding oval cysts in bronchial lavage fluid supports a diagnosis of Pneumocystis pneumonia. C Large domestic animals such as cows and sheep are an important reservoir of human infection with this organism. D Patients with a CD4 count below 200 should receive the vaccine containing the surface glycoprotein as the immunogen. E Transmission occurs by the ingestion of food contaminated with the organism, after which it enters the bloodstream and is transported to the lung.
B Finding oval cysts in bronchial lavage fluid supports a diagnosis of Pneumocystis pneumonia.
Regarding schistosomes, which one of the following statements is the most accurate? A The visual appearance of male and female schistosomes is the same. B Humans are infected by schistosomes when cercariae penetrate the skin. C Infection of freshwater fish is a required part of the life cycle of schistosomes. D The pathology of schistosomiasis is principally caused by the cercariae entering hepatocytes and killing them. E Infection by nonhuman schistosomes can cause meningitis in people who swim in certain lakes in the United States.
B Humans are infected by schistosomes when cercariae penetrate the skin.
The main anatomic location of Schistosoma mansoni adult worms is: A Lung alveoli B Intestinal venules C Renal tubules D Bone marrow
B Intestinal venules
Which one of the following protozoa primarily infects macrophages? A Plasmodium vivax B Leishmania donovani C Trypanosoma cruzi D Trichomonas vaginalis
B Leishmania donovani
Transmitted by the bite of a deer fly or mango fly A Dracunculus medinensis B Loa loa C Onchocerca volvulus D Wuchereria bancrofti E Toxocara canis
B Loa loa
Your patient is a 5-year-old boy who complains of perianal itching, especially at night. A "Scotch tape" preparation reveals the eggs of Enterobius in the microscope. Which one of the following is the best drug to treat his pinworm infection? A Ivermectin B Mebendazole C Pentamidine D Praziquantel E Pyrimethamine and sulfadiazine
B Mebendazole
Regarding Diphyllobothrium latum, which one of the following is most accurate? A Cattle are the most important intermediate hosts. B Megaloblastic anemia may occur as a result of vitamin B12 deficiency. C The laboratory diagnosis depends on finding a scolex with hooklets in the stool. D Infection is acquired by the ingestion of eggs in food or water contaminated with human feces. E Larvae migrate from the gastrointestinal tract via the portal circulation to the liver, where abscesses can occur.
B Megaloblastic anemia may occur as a result of vitamin B12 deficiency.
Your patient is a 30-year-old woman who returned from traveling in Eastern Europe 1 week ago. While on the trip, she experienced anorexia, nausea but no vomiting, and abdominal bloating. For the past 2 days, she has had explosive watery diarrhea. An examination of her stool revealed pear-shaped, flagellated, motile organisms. Which one of the following is the best antibiotic to treat the infection? A Chloroquine B Metronidazole C Nifurtimox D Praziquantel E Stibogluconate
B Metronidazole
Each of the following statements concerning trichinosis is correct EXCEPT: A Trichinosis is acquired by eating undercooked pork. B Trichinosis is caused by a protozoan that has both a trophozoite and a cyst stage in its life cycle. C Trichinosis can be diagnosed by seeing cysts in muscle biopsy specimens. D Eosinophilia is a prominent finding.
B Trichinosis is caused by a protozoan that has both a trophozoite and a cyst stage in its life cycle.
Each of the following statements concerning Trypanosoma cruzi is correct EXCEPT: A Trypanosoma cruzi is transmitted by the reduviid bug. B Trypanosoma cruzi occurs primarily in tropical Africa. C Trypanosoma cruzi can be diagnosed by seeing amastigotes in a bone marrow aspirate. D Trypanosoma cruzi typically affects heart muscle, leading to cardiac failure.
B Trypanosoma cruzi occurs primarily in tropical Africa
Your patient is a 35-year-old woman with severe upper abdominal pain for the past hour. There is no nausea, vomiting, or diarrhea. You suspect she may have cholecystitis, pancreatitis, or a perforated viscus but first ask her if she has ingested raw fish recently. She says yes and tells you that she had sashimi the night before last. Endoscopy reveals a larva in the gastric mucosa. Of the following, which one is the most likely cause? A Ancylostoma caninum B Ancylostoma duodenale C Anisakis simplex D Toxocara canis E Trichuris trichiura
C Anisakis simplex
Pigs or dogs are the source of human infection by each of the following parasites EXCEPT: A Echinococcus granulosus B Taenia solium C Ascaris lumbricoides D Trichinella spiralis
C Ascaris lumbricoides
Each of the following statements concerning Ascaris lumbricoides is correct EXCEPT: A Ascaris lumbricoides is one of the largest nematodes. B Ascaris lumbricoides is transmitted by ingestion of eggs. C Both dogs and cats are intermediate hosts of A. lumbricoides. D Ascaris lumbricoides can cause pneumonia.
C Both dogs and cats are intermediate hosts of A. lumbricoides.
Regarding leishmaniasis, which one of the following is most accurate? A Mefloquine is effective in preventing disease caused by L. donovani. B Large domestic animals such as cattle are the principal reservoir of L. donovani. C Both visceral leishmaniasis and cutaneous leishmaniasis are transmitted by the bite of sandflies. D Marked enlargement of the heart on chest X-ray is a typical finding of visceral leishmaniasis. E Pathologists examining a specimen for the presence of L. donovani should look primarily at eosinophils in the peripheral blood.
C Both visceral leishmaniasis and cutaneous leishmaniasis are transmitted by the bite of sandflies.
Children at day care centers in the United States have a high rate of infection with which one of the following? A Ascaris lumbricoides B Entamoeba histolytica C Enterobius vermicularis D Necator americanus
C Enterobius vermicularis
Each of the following parasites passes through the lung during human infection EXCEPT: A Strongyloides stercoralis B Necator americanus C Enterobius vermicularis D Ascaris lumbricoides
C Enterobius vermicularis
Your patient is a 30-year-old woman who returned from traveling in Eastern Europe 1 week ago. While on the trip, she experienced anorexia, nausea but no vomiting, and abdominal bloating. For the past 2 days, she has had explosive watery diarrhea. An examination of her stool revealed pear-shaped, flagellated, motile organisms. Of the following, which one is the most likely cause of this infection? A Cryptosporidium hominis B Entamoeba histolytica C Giardia lamblia D Trichomonas vaginalis
C Giardia lamblia
Each of the following statements concerning Giardia lamblia is correct EXCEPT: A Giardia lamblia has both a trophozoite and a cyst stage in its life cycle. B Giardia lamblia is transmitted by the fecal-oral route from both human and animal sources. C Giardia lamblia causes hemolytic anemia. D Giardia lamblia can be diagnosed by the string test in which a weighted string is swallowed and passes into the upper GI tract.
C Giardia lamblia causes hemolytic anemia.
Each of the following statements concerning kala-azar is correct EXCEPT: A Kala-azar is caused by Leishmania donovani. B Kala-azar is transmitted by the bite of sandflies. C Kala-azar occurs primarily in rural Latin America. D Kala-azar can be diagnosed by finding amastigotes in bone marrow.
C Kala-azar occurs primarily in rural Latin America.
Regarding Cryptosporidium hominis, which one of the following is most accurate? A Humans are the only reservoir for C. hominis. B Microscopic examination of the diarrheal stool reveals both red cells and white cells. C Laboratory diagnosis involves seeing cysts of the organism in an acid-fast stain of the stool. D Cryptosporidium hominis is typically acquired by the ingestion of trophozoites in contaminated food or water. E In immunocompromised patients, such as AIDS patients with a very low CD4 count, disseminated disease occurs that typically involves the brain and meninges.
C Laboratory diagnosis involves seeing cysts of the organism in an acid-fast stain of the stool.
Your patient is a 10-year-old girl with a fever and a severe headache for the past 2 days. Pertinent history includes swimming in a pond near their home in rural California in August. On exam, nuchal rigidity was observed and a lumbar puncture was performed. The spinal fluid white blood cell count was 12,200 with 80% neutrophils. Microscopic examination of a wet mount of spinal fluid revealed motile trophozoites. Of the following, which one is the most likely cause? A Babesia microti B Cryptosporidium parvum C Naegleria fowleri D Toxoplasma gondii E Trypanosoma cruzi
C Naegleria fowleri
One of the most important public health measures in the United States in the twentieth century was recommending that children in rural areas wear shoes. This effort was designed to prevent infection through the feet with which one of the following organisms? A Ascaris lumbricoides B Enterobius vermicularis C Necator americanus D Onchocerca volvulus E Trichuris trichiura
C Necator americanus
Causes river blindness A Dracunculus medinensis B Loa loa C Onchocerca volvulus D Wuchereria bancrofti E Toxocara canis
C Onchocerca volvulus
Your patient is a 20-year-old woman who is a recent immigrant from Central America. On routine exam, a stool ova and parasite test reveal eggs resembling those of T. solium. Which one of the following is the best choice of drug to treat this patient? A Ivermectin B Pentamidine C Praziquantel D Pyrimethamine and sulfadiazine E Stibogluconate
C Praziquantel
Your patient is a 30-year-old man with low-grade perineal pain for several weeks who had an episode of painful ejaculation and postcoital hematuria yesterday. He is in a long-standing monogamous relationship. He has traveled extensively throughout the world during the past 10 years. Urinalysis and urine culture were negative. Cytologic examination of cells in the urine revealed no tumor cells. Cystoscopy revealed several polypoid lesions, and a biopsy of a lesion was taken. The tissue was examined in the light microscope, and eggs with a terminal spine were seen. Of the following, which one is the MOST likely cause? A Clonorchis sinensis B Paragonimus westermani C Schistosoma haematobium D Schistosoma japonicum E Schistosoma mansoni
C Schistosoma haematobium
Each of the following statements concerning Schistosoma haematobium is correct EXCEPT: A Schistosoma haematobium is acquired by humans when cercariae penetrate the skin. B Snails are intermediate hosts of S. haematobium. C Schistosoma haematobium eggs have no spine. D Schistosoma haematobium infection predisposes to bladder carcinoma.
C Schistosoma haematobium eggs have no spine.
Each of the following statements concerning sleeping sickness is correct EXCEPT: A Sleeping sickness is caused by a trypanosome. B Sleeping sickness is transmitted by tsetse flies. C Sleeping sickness can be diagnosed by finding eggs in the stool. D Sleeping sickness occurs primarily in tropical Africa.
C Sleeping sickness can be diagnosed by finding eggs in the stool.
Which one of the following nematodes is transmitted by a filariform larva penetrating the skin? A Anisakis simplex B Onchocerca volvulus C Strongyloides stercoralis D Toxocara canis E Trichuris trichiura
C Strongyloides stercoralis
Your patient is a 60-year-old man with abdominal pain, vomiting, and weight loss for the past 2 months. He has a history of asthma that requires 20 mg of prednisone daily to control. He lived most of his life in Cuba, moved to Spain 10 years ago, and has lived in this country for 1 year. Abdominal exam is normal, and radiographic studies are unrevealing. His white blood cell count is 10,900 with 16% eosinophils. Examination of the stool reveals rhabditiform larvae. Of the following, which organism is the MOST likely cause? A Ascaris lumbricoides B Onchocerca volvulus C Strongyloides stercoralis D Toxocara canis E Trichinella spiralis
C Strongyloides stercoralis
A cestode (tapeworm) acquired by eating undercooked pork A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
C Taenia solium
Causes cysticercosis in humans A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
C Taenia solium
Regarding Trypanosoma cruzi, which one of the following is most accurate? A Humans are the main reservoir of T. cruzi. B The drug of choice for the acute phase of Chagas' disease is chloroquine. C The vector for T. cruzi, the cause of Chagas' disease, is the reduviid (cone-nosed) bug. D Seeing trypomastigotes in a muscle biopsy supports the diagnosis of Chagas' disease. E The main site of disease caused by T. cruzi is skeletal muscle, resulting in severe muscle pain.
C The vector for T. cruzi, the cause of Chagas' disease, is the reduviid (cone-nosed) bug.
Regarding drugs used to treat or prevent malaria, which one of the following is most accurate? A The combination of atovaquone and proguanil is useful for the treatment of acute malaria but not for prevention. B Chloroquine is the drug of choice in malaria caused by P. falciparum because resistance to the drug is rare. C Mefloquine is useful for the prevention of chloroquine-sensitive P. falciparum but not for chloroquine-resistant strains. D Artemisinin derivatives, such as artesunate and artemether, are effective in the treatment of multiple-drug resistant P. falciparum. E Primaquine is useful in the treatment of infections caused by P. falciparum because it kills the hypnozoites residing in the liver.
D Artemisinin derivatives, such as artesunate and artemether, are effective in the treatment of multiple-drug resistant P. falciparum.
A trematode (fluke) acquired by eating undercooked fish A Giardia lamblia B Plasmodium vivax C Taenia saginata D Clonorchis sinensis E Enterobius vermicularis
D Clonorchis sinensis
Primarily affects the biliary ducts A Giardia lamblia B Plasmodium vivax C Taenia saginata D Clonorchis sinensis E Enterobius vermicularis
D Clonorchis sinensis
Each of the following statements concerning Diphyllobothrium latum is correct EXCEPT: A Diphyllobothrium latum is transmitted by undercooked fish. B Diphyllobothrium latum has operculated eggs. C Diphyllobothrium latum causes a megaloblastic anemia due to vitamin B12 deficiency. D Diphyllobothrium latum is a tapeworm that has a scolex with a circle of hooks.
D Diphyllobothrium latum is a tapeworm that has a scolex with a circle of hooks.
Each of the following statements concerning hookworm infection is correct EXCEPT: A Hookworm infection can cause anemia. B Hookworm infection is acquired by humans when filariform larvae penetrate the skin. C Hookworm infection is caused by Necator americanus. D Hookworm infection can be diagnosed by finding the trophozoite in the stool.
D Hookworm infection can be diagnosed by finding the trophozoite in the stool.
A trematode (fluke) acquired by eating undercooked crab meat A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
D Paragonimus westermani
Laboratory diagnosis based on finding eggs in sputum A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
D Paragonimus westermani
Each of the following statements concerning Pneumocystis carinii is correct EXCEPT: A Pneumocystis carinii infections primarily involve the respiratory tract. B Pneumocystis carinii can be diagnosed by seeing cysts in tissue. C Pneumocystis carinii infections are symptomatic primarily in immunocompromised patients. D Pneumocystis carinii symptomatic infections can be prevented by administering penicillin orally
D Pneumocystis carinii symptomatic infections can be prevented by administering penicillin orally.
Which one of the following is the drug of choice for infections with S. mansoni and S. haematobium? A Albendazole B Metronidazole C Nifurtimox D Praziquantel E Stibogluconate
D Praziquantel
Your patient is a 15-year-old girl with a 2-week history of headache and vomiting and a 3-day history of confusion and incoherent speech. She was born in Ecuador but moved to this country 5 years ago. Magnetic resonance imaging (MRI) of the brain reveals multiple lesions bilaterally. The following day, she has a seizure and dies. On autopsy, the brain lesions consist of a cyst-like sac containing a larva. Of the following, which one is the most likely cause? A Dipylidium latum B Echinococcus granulosus C Taenia saginata D Taenia solium
D Taenia solium
Each of the following statements concerning hydatid cyst disease is correct EXCEPT: A The disease is caused by Echinococcus granulosus. B The cysts occur primarily in the liver. C The disease is caused by a parasite whose adult form lives in dogs' intestines. D The disease occurs primarily in tropical Africa.
D The disease occurs primarily in tropical Africa.
Each of the following statements concerning malaria is correct EXCEPT: A The female Anopheles mosquito is the vector. B Early in infection, sporozoites enter hepatocytes. C Release of merozoites from red blood cells causes periodic fever and chills. D The principal site of gametocyte formation is the human gastrointestinal tract.
D The principal site of gametocyte formation is the human gastrointestinal tract.
Each of the following statements concerning Toxoplasma gondii is correct EXCEPT: A Toxoplasma gondii can be transmitted across the placenta to the fetus. B Toxoplasma gondii can be transmitted by cat feces. C Toxoplasma gondii can cause encephalitis in immunocompromised patients. D Toxoplasma gondii can be diagnosed by finding trophozoites in the stool.
D Toxoplasma gondii can be diagnosed by finding trophozoites in the stool.
Your patient is a 40-year-old man with fever, myalgia, and facial swelling. White blood cell count was 14,400 with 24% eosinophils. Additional history reveals that he shot a bear in Canada and ate some of it about 6 weeks ago. He emphasized that he likes his meat rare. A muscle biopsy was performed, and a hematoxylin and eosin (H&E) stain of the tissue showed coiled larvae within skeletal muscle. Of the following, which one is the most likely cause? A Ancylostoma caninum B Anisakis simplex C Necator americanus D Trichinella spiralis E Wuchereria bancrofti
D Trichinella spiralis
Each of the following statements concerning Trichomonas vaginalis is correct EXCEPT: A Trichomonas vaginalis is transmitted sexually. B Trichomonas vaginalis can be diagnosed by visualizing the trophozoite. C Trichomonas vaginalis can be treated effectively with metronidazole. D Trichomonas vaginalis causes bloody diarrhea.
D Trichomonas vaginalis causes bloody diarrhea
Transmitted by mosquito A Dracunculus medinensis B Loa loa C Onchocerca volvulus D Wuchereria bancrofti E Toxocara canis
D Wuchereria bancrofti
Causes perianal itching as the most prominent symptom A Giardia lamblia B Plasmodium vivax C Taenia saginata D Clonorchis sinensis E Enterobius vermicularis
E Enterobius vermicularis
A nematode (roundworm) transmitted primarily from child to child A Giardia lamblia B Plasmodium vivax C Taenia saginata D Clonorchis sinensis E Enterobius vermicularis
E Enterobius vermicularis
Regarding Giardia lamblia, which one of the following is most accurate? A The drug of choice for giardiasis is chloroquine. B In giardiasis, ova and parasite (O&P) analysis of the stool reveals sporozoites in the feces. C Giardia lamblia produces an enterotoxin that increases cyclic AMP within the enterocyte, resulting in diarrhea. D Giardia lamblia infection is acquired by ingestion of food or water contaminated with human feces only (i.e., there is no animal reservoir for this organism). E Infection by G. lamblia occurs principally in the small intestine, frequently resulting in the malabsorption of fat and foul-smelling, frothy, fat-containing stools.
E Infection by G. lamblia occurs principally in the small intestine, frequently resulting in the malabsorption of fat and foul-smelling, frothy, fat-containing stools.
Your patient is a 35-year-old woman who has just had a seizure. A CT scan shows a ring-enhancing lesion in her brain. History reveals that she is an intravenous drug user and is HIV antibody positive with a CD4 count of 30. Serologic tests confirm that the patient is infected with Toxoplasma gondii. Which one of the following is the best choice of drug to treat her cerebral toxoplasmosis? A Artemether B Atovaquone C Mefloquine D Metronidazole E Pyrimethamine and sulfadiazine
E Pyrimethamine and sulfadiazine
A nematode (roundworm) acquired when filariform larvae penetrate the skin A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
E Strongyloides stercoralis
Autoinfection within humans, especially in immunocompromised patients A Entamoeba histolytica B Plasmodium falciparum C Taenia solium D Paragonimus westermani E Strongyloides stercoralis
E Strongyloides stercoralis
Acquired by ingestion of worm eggs A Dracunculus medinensis B Loa loa C Onchocerca volvulus D Wuchereria bancrofti E Toxocara canis
E Toxocara canis
Causes visceral larva migrans A Dracunculus medinensis B Loa loa C Onchocerca volvulus D Wuchereria bancrofti E Toxocara canis
E Toxocara canis
Your patient is a 35-year-old woman who has just had a seizure. A CT scan shows a ring-enhancing lesion in her brain. History reveals that she is an intravenous drug user and is HIV antibody positive with a CD4 count of 30. Serologic tests confirm that the patient is infected with Toxoplasma gondii. She was treated and recovered without sequelae. Antiretroviral therapy was instituted. As long as her CD4 count remains below 100, she should receive chemoprophylaxis to prevent recurrent disease caused by T. gondii. Which one of the following is the best chemoprophylactic drug? A Artesunate B Metronidazole C Pentamidine D Primaquine E Trimethoprim-sulfamethoxazole
E Trimethoprim-sulfamethoxazole
Your patient is a 20-year-old man who, while playing soccer, experienced palpitations and dizziness and then fainted. An electrocardiogram showed right bundle branch block. Holter monitoring showed multiple runs of ventricular tachycardia. A ventricular myocardial biopsy was performed. Microscopic examination revealed a lymphocytic inflammatory process surrounding areas containing amastigotes. The patient was born and raised in rural El Salvador and came to this country 2 years ago. Of the following, which one is the most likely cause? A Leishmania donovani B Plasmodium falciparum C Toxoplasma gondii D Trypanosoma brucei E Trypanosoma cruzi
E Trypanosoma cruzi
