Micro 68 and 69 Flashcards

A parasite antigen cross-links IgE on mast cells, causing histamine release. Which reaction is occurring?

A. Type IV cell-mediated

B. Type I anaphylactic

C. Type III immune-complex

D. Type II cytotoxic

Which outcome is characteristic of a type I reaction?

A. Antigen-bearing cell lysis and bronchospasm

B. Glomerular complex deposition and bronchospasm

C. Macrophage activation and anaphylactic shock

D. Bronchospasm and anaphylactic shock

Which infections are examples of type I reactions?

A. Helminths and African trypanosomiasis

B. Malaria and schistosomiasis

C. Chagas disease and African trypanosomiasis

D. Leishmaniasis and schistosomiasis

Antibodies bind microbial antigens on cell surfaces, activating complement or ADCC. Which reaction is this?

A. Type I anaphylactic

B. Type III immune-complex

C. Type II cytotoxic

D. Type IV cell-mediated

Which outcome is characteristic of a type II reaction?

A. Lysis of antigen-bearing cells

B. Bronchospasm from histamine

C. Glomerular complex deposition

D. Mononuclear cell accumulation

Trypanosoma cruzi infection is an example of which immunopathologic reaction?

A. Type III immune-complex

B. Type IV cell-mediated

C. Type I anaphylactic

D. Type II cytotoxic

Antibodies combine with extracellular parasite antigens to form circulating complexes. Which reaction results?

A. Type II cytotoxic

B. Type III immune-complex

C. Type I anaphylactic

D. Type IV cell-mediated

Which outcome is characteristic of type III reactions?

A. Mast-cell histamine release

B. Antigen-bearing cell lysis

C. Immune-complex tissue deposition

D. Direct T-cell cytotoxicity

Which diseases may produce type III immune-complex reactions?

A. Malaria, giardiasis, trypanosomiasis

B. Helminth infection, schistosomiasis, trypanosomiasis

C. Leishmaniasis, giardiasis, trypanosomiasis

D. Malaria, schistosomiasis, trypanosomiasis

Sensitized T cells release lymphokines and trigger cytotoxicity after encountering parasite antigen. Which reaction occurs?

A. Type IV cell-mediated

B. Type I anaphylactic

C. Type II cytotoxic

D. Type III immune-complex

Which result is characteristic of type IV reactions?

A. Immediate mast-cell degranulation

B. Complement-mediated cell lysis

C. Macrophage activation and tissue damage

D. Circulating immune-complex deposition

Which infections may produce type IV reactions?

A. Helminth infection and Chagas disease

B. Leishmaniasis, schistosomiasis, trypanosomiasis

C. Malaria, schistosomiasis, babesiosis

D. Giardiasis, cryptosporidiosis, schistosomiasis

After oral ingestion, which parasite can cause severe dysentery?

A. Giardia duodenalis

B. Cryptosporidium species

C. Entamoeba histolytica

D. Toxoplasma gondii

Babesia spp. use which receptor for RBC attachment?
A. Duffy antigen
B. Complement-mediated C3b receptor
C. Glycophorin B
D. CR2 receptor
E. Lectin binding

Which parasites commonly enter through larval skin penetration?

A. Ascaris species

B. Hookworms

C. Taenia species

D. Trichuris species

Which nematode infects through larval skin penetration?

A. Enterobius vermicularis

B. Strongyloides stercoralis

C. Ascaris lumbricoides

D. Trichuris trichiura

Which organism is transmitted transplacentally?
A. Giardia spp.
B. Plasmodium spp.
C. Toxoplasma gondii
D. Trypanosoma spp.
E. Leishmania spp.

Which vector transmits human malaria?

A. Ixodes tick

B. Sandfly

C. Tsetse fly

D. Anopheles mosquito

Which vector transmits mosquito-borne filarial infections?

A. Male mosquito

B. Sandfly

C. Tsetse fly

D. Female mosquito

How does Trypanosoma cruzi enter humans?

A. Feces contaminate wounds or mucosa

B. Saliva enters during feeding

C. Larvae penetrate intact skin

D. Oocysts contaminate drinking water

Which host cell can Trypanosoma cruzi infect?

A. Erythrocyte

B. Hepatocyte

C. Fibroblast

D. Enterocyte

Which host cell is infected by Babesia?

A. Macrophage

B. Red blood cell

C. Fibroblast

D. Intestinal epithelial cell

Which Plasmodium form invades red blood cells?

A. Sporozoite

B. Gametocyte

C. Ookinete

D. Merozoite

Which organism is associated with colitis?
A. Entamoeba histolytica
B. Toxocara spp.
C. Leishmania donovani
D. Plasmodium falciparum
E. Onchocerca volvulus

Invasive amebiasis requires Entamoeba adherence where?

A. Gastric epithelium

B. Small intestinal villi

C. Biliary epithelium

D. Colonic epithelium

Which parasite causes diarrhea/dysentery?
A. Loa loa
B. Giardia duodenalis
C. Wuchereria bancrofti
D. Dirofilaria immitis
E. Echinococcus multilocularis

Which surface protein mediates Entamoeba adherence?

A. Lectin

B. Integrin

C. Cadherin

D. Selectin

Which feature distinguishes pathogenic Entamoeba histolytica?

A. Ventral adhesive disc

B. Apical penetration complex

C. Duffy-binding protein

D. Galactose-inhibitable surface lectin

Which erythrocyte receptor binds Plasmodium vivax?

A. Glycophorin A

B. Duffy antigen

C. CD55

D. Complement receptor 1

Which population commonly lacks the Duffy antigen?

A. West Africans

B. Northern Europeans

C. East Asians

D. Native Australians

How does Giardia attach to intestinal epithelium?

A. Apical complex

B. Ventral adhesive disc

C. Galactose lectin

D. Hooks and suckers

Which temperature favors Leishmania donovani growth?

A. 20°C

B. 25°C

C. 30°C

D. 37°C

Which temperature favors Leishmania tropica growth?

A. 4°C to 10°C

B. 15°C to 20°C

C. 25°C to 30°C

D. 37°C to 42°C

Which host cell is targeted by Leishmania?

A. Red blood cell

B. Macrophage

C. Fibroblast

D. Enterocyte

Which parasite secretes an amebic ionophore?

A. Giardia duodenalis

B. Toxoplasma gondii

C. Entamoeba histolytica

D. Leishmania donovani

Which parasite can obstruct the ileocecal valve?

A. Enterobius vermicularis

B. Ascaris lumbricoides

C. Strongyloides stercoralis

D. Trichuris trichiura

Which parasite may obstruct the bile ducts?

A. Necator americanus

B. Ascaris lumbricoides

C. Wuchereria bancrofti

D. Onchocerca volvulus

Lymphatic obstruction causing elephantiasis suggests which parasite?

A. Onchocerca volvulus

B. Loa loa

C. Wuchereria bancrofti

D. Trichinella spiralis

Ingesting Taenia solium eggs may cause what?

A. Intestinal taeniasis

B. Hydatid disease

C. Diphyllobothriasis

D. Cysticercosis

What produces tissue injury during cysticercosis?

A. Adult worm attachment

B. Egg-induced hemolysis

C. Expanding larval cyst pressure

D. Toxin-mediated neuronal death

Which parasite increases bladder carcinoma risk?

A. Schistosoma haematobium

B. Schistosoma mansoni

C. Clonorchis sinensis

D. Taenia solium

Which helminth causes biliary tract disease and is associated with cholangiocarcinoma?

A. Fasciola hepatica

B. Paragonimus westermani

C. Clonorchis sinensis

D. Schistosoma haematobium

Trypanosoma cruzi is associated with which reaction?

A. Type I hypersensitivity

B. Type III hypersensitivity

C. Type IV hypersensitivity

D. Type II hypersensitivity

Malaria may cause which hypersensitivity reaction?

A. Type I hypersensitivity

B. Type II hypersensitivity

C. Type IV hypersensitivity

D. Type III hypersensitivity

Schistosoma mansoni proteinases can degrade what?

A. Immunoglobulins

B. Host DNA

C. Erythrocyte glycophorin

D. Biliary cholesterol

Which parasite inhibits phagolysosomal fusion?

A. Entamoeba histolytica

B. Giardia duodenalis

C. Leishmania tropica

D. Toxoplasma gondii

Compared with many viral infections, parasitoses are often what?

A. Fulminant

B. Transient

C. Chronic

D. Self-limited

Most human parasites originate outside the host. What are they?

A. Exogenous

B. Endogenous

C. Commensal

D. Autochthonous

What is a common route of parasite entry?

A. Respiratory droplets

B. Sexual transmission

C. Oral ingestion

D. Vertical transmission

Besides ingestion, parasites commonly enter by what?

A. Axonal transport

B. Blood transfusion

C. Skin penetration

D. Respiratory aspiration

Many parasitic diseases are transmitted through what?

A. Arthropod bites

B. Respiratory droplets

C. Sexual contact

D. Contaminated needles

Which molecules help parasites attach to host cells?

A. Endotoxins and porins

B. Adhesins and glycoproteins

C. Sterols and phospholipids

D. Histones and ribosomes

Which sugars mediate Entamoeba mucosal adherence?

A. Glucose and fructose

B. Mannose and fucose

C. Ribose and deoxyribose

D. Galactose and GalNAc

Which erythrocyte receptor facilitates Plasmodium vivax attachment?

A. Glycophorin A

B. Complement receptor 1

C. Duffy blood group antigen

D. CD36

Duffy-negative erythrocytes have which effect on Plasmodium vivax?

A. Greatly reduced susceptibility

B. Increased merozoite invasion

C. Enhanced parasite replication

D. Complete universal susceptibility

Entamoeba histolytica degrades epithelial basement membranes using what?

A. Phospholipids

B. Surface lectins

C. Ion channels

D. Proteinases

Entamoeba histolytica disrupts epithelial attachment by degrading what?

A. Host immunoglobulins

B. Cell-anchoring proteins

C. Erythrocyte receptors

D. Intestinal carbohydrates

Which Entamoeba histolytica product can lyse neutrophils?

A. Phospholipases

B. Siderophores

C. Hemolysins

D. Collagen fibers

Which parasite produces an ionophore-like cytolytic protein?

A. Giardia duodenalis

B. Toxoplasma gondii

C. Entamoeba histolytica

D. Leishmania donovani

Neutrophil lysis during amebiasis releases substances causing what?

A. Parasite encystment

B. Antibody neutralization

C. Mucosal healing

D. Host tissue injury

Which helminth characteristic can directly increase tissue damage?

A. Intracellular replication

B. Large body size

C. Binary fission

D. Antigenic drift

Helminth migration causes injury primarily through what?

A. Mechanical tissue disruption

B. Antibody class switching

C. Intracellular toxin synthesis

D. Viral-like budding

Why can long-lived helminths cause prolonged pathology?

A. They rapidly lyse cells

B. They produce bacterial spores

C. They persist within host tissues

D. They require repeated inoculation

Which parasites commonly obstruct internal organs mechanically?

A. Protozoa

B. Arthropods

C. Fungi

D. Helminths

Helminths can damage tissues while moving by doing what?

A. Forming immune complexes

B. Migrating through tissues

C. Invading erythrocytes

D. Inhibiting DNA synthesis

Expanding helminths can damage organs by increasing what?

A. Local tissue pressure

B. Serum antibody concentration

C. Intracellular calcium

D. Epithelial turnover

Which strategy helps many protozoa evade immunity?

A. Extracellular spore formation

B. Thick bacterial capsules

C. Intracellular residence in macrophages

D. Continuous antigen secretion

Visceral leishmaniasis commonly affects which hematopoietic site?

A. Thymic cortex

B. Bone marrow

C. Lymphatic valves

D. Adrenal medulla

Which organism can cause granulomatous amebic encephalitis?

A. Naegleria fowleri

B. Entamoeba histolytica

C. Giardia duodenalis

D. Acanthamoeba species

Which parasite can cause granulomatous amebic encephalitis?

A. Balamuthia mandrillaris

B. Trichomonas vaginalis

C. Cryptosporidium parvum

D. Neobalantidium coli

Which parasitic infection commonly causes chorioretinitis?

A. Babesiosis

B. Giardiasis

C. Toxoplasmosis

D. Trichuriasis

Which organism causes ocular larva migrans?

A. Onchocerca volvulus

B. Acanthamoeba species

C. Trichinella spiralis

D. Toxocara canis

Which parasitic disease may mimic retinoblastoma?

A. Ocular toxocariasis

B. Visceral leishmaniasis

C. Cerebral malaria

D. Onchocerciasis

A child has nocturnal anal pruritus. Which parasite is likely?

A. Trichuris trichiura

B. Strongyloides stercoralis

C. Enterobius vermicularis

D. Ascaris lumbricoides

Chronic Trypanosoma cruzi infection can produce what?

A. Rectal prolapse

B. Megacolon

C. Biliary obstruction

D. Peptic ulceration

Which cardiac disorder can Trypanosoma cruzi cause?

A. Restrictive cardiomyopathy

B. Hypertrophic cardiomyopathy

C. Acute pericarditis

D. Dilated cardiomyopathy

Trypanosoma cruzi may damage conduction tissue, causing what?

A. Complete heart block

B. Sinus tachycardia

C. Mitral valve stenosis

D. Aortic valve rupture

Heavy Trichuris trichiura infection may cause what?

A. Biliary obstruction

B. Intestinal volvulus

C. Rectal prolapse

D. Gastric outlet obstruction

Which liver fluke can cause biliary obstruction?

A. Fasciolopsis buski

B. Schistosoma mansoni

C. Paragonimus westermani

D. Clonorchis sinensis

Severe Plasmodium falciparum infection may cause what?

A. Acute renal failure

B. Rectal prolapse

C. Vitamin B12 deficiency

D. Biliary obstruction

Which parasite produces inflammatory skeletal-muscle infection?

A. Wuchereria bancrofti

B. Diphyllobothrium latum

C. Trichinella spiralis

D. Enterobius vermicularis

Cutaneous infection causing chronic skin ulcers suggests what?

A. Babesiosis

B. Leishmaniasis

C. Giardiasis

D. Cysticercosis

Which hookworm commonly causes iron-deficiency anemia?

A. Ancylostoma duodenale

B. Ascaris lumbricoides

C. Enterobius vermicularis

D. Trichinella spiralis

Which parasite can cause iron-deficiency anemia through blood loss?

A. Trichuris trichiura

B. Wuchereria bancrofti

C. Onchocerca volvulus

D. Necator americanus

Which parasite may cause vitamin B12 deficiency?

A. Taenia solium

B. Echinococcus granulosus

C. Diphyllobothrium latum

D. Hymenolepis nana

Megaloblastic anemia may occur with which infection?

A. Diphyllobothriasis

B. Ascariasis

C. Enterobiasis

D. Trichinellosis

Contact lens–associated parasitic keratitis suggests which organism?

A. Balamuthia mandrillaris

B. Acanthamoeba species

C. Toxoplasma gondii

D. Entamoeba histolytica

Which filarial parasite can cause inflammatory keratitis?

A. Wuchereria bancrofti

B. Brugia malayi

C. Loa loa

D. Onchocerca volvulus

Which parasite is associated with malaria?
A. Plasmodium falciparum
B. Babesia spp.
C. Toxoplasma gondii
D. Entamoeba histolytica
E. Leishmania donovani

Which parasite is associated with filariasis?
A. Toxoplasma gondii
B. Wuchereria bancrofti
C. Entamoeba histolytica
D. Giardia duodenalis
E. Plasmodium malariae

Which parasite is associated with meningoencephalitis?
A. Giardia duodenalis
B. Entamoeba histolytica
C. Naegleria fowleri
D. Ascaris lumbricoides
E. Trichuris trichiura

Which organism causes granulomatous encephalitis?
A. Toxoplasma gondii
B. Acanthamoeba spp.
C. Plasmodium falciparum
D. Schistosoma mansoni
E. Fasciola hepatica

Which parasite is associated with brain abscess formation?
A. Toxoplasma gondii
B. Enterobius vermicularis
C. Giardia duodenalis
D. Loa loa
E. Brugia malayi

Which parasite is linked to liver abscess?
A. Fasciola hepatica
B. Plasmodium malariae
C. Babesia spp.
D. Loa loa
E. Brugia malayi

Which organism is linked to eosinophilic meningitis?
A. Plasmodium vivax
B. Angiostrongylus cantonensis
C. Leishmania tropica
D. Babesia spp.
E. Dirofilaria immitis

Which organism is associated with chorioretinitis?
A. Toxoplasma gondii
B. Giardia duodenalis
C. Ascaris lumbricoides
D. Fasciolopsis buski
E. Necator americanus

Which organism causes hepatitis?
A. Entamoeba histolytica
B. Toxoplasma gondii
C. Giardia duodenalis
D. Cyclospora cayetanensis
E. Cystoisospora belli

Most protozoan parasites replicate:
A. Only outside host
B. Only in vectors
C. Intracellularly or extracellularly in host
D. Only in environment
E. Not at all

Which organism is linked to cirrhosis/hepatosplenomegaly?
A. Schistosoma mansoni
B. Giardia duodenalis
C. Enterobius vermicularis
D. Trichomonas vaginalis
E. Dirofilaria immitis

Which parasite is associated with cystitis/hematuria?
A. Schistosoma haematobium
B. Loa loa
C. Brugia malayi
D. Wuchereria bancrofti
E. Onchocerca volvulus

Which organism is associated with renal failure?

A. Plasmodium spp.

B. Giardia duodenalis

C. Entamoeba histolytica

D. Cyclospora cayetanensis

Helminths capable of infecting humans typically:
A. Replicate extensively in host
B. Do not replicate in host
C. Replicate only in blood
D. Replicate only in liver
E. Replicate only intracellularly

Which parasite is associated with pneumonitis?
A. Dirofilaria immitis
B. Ascaris lumbricoides
C. Leishmania tropica
D. Babesia spp.
E. Loa loa

Which parasite is associated with generalized myositis?
A. Trichinella spiralis
B. Plasmodium vivax
C. Schistosoma mansoni
D. Fasciolopsis buski
E. Onchocerca volvulus

Which organism causes lymphedema?
A. Toxoplasma gondii
B. Trypanosoma cruzi
C. Wuchereria bancrofti
D. Giardia duodenalis
E. Entamoeba histolytica

Which factor most strongly influences the severity of many parasitic infections?
A. Infecting dose
B. Oxygen tension
C. Host age only
D. Blood type exclusively
E. Viral coinfection

Entamoeba histolytica typically causes disease when:
A. Contacting intact skin
B. Inhaled into lungs
C. Injected intravenously
D. Absorbed through hair follicles
E. Ingested orally