Microbio-Parasitology And Protozoa

Question 0

Diagnosis: Serology and/or trophozoites (w/RBC in the cytoplasm); or cysts with up to 4 nuclei in stool.
Disease: bloody diarrhea, liver abscess (anchovy paste exudate), RUQ pain (histol. shows flask-shaped ulcer if colon rupture.
Transmission: cysts in water
Treatment: Metronidazole; iodoquinol for asymptomatic cyst passers.

Answer 0

Entamoeba histolitica

Question 1

Diagnosis: Trophocytes, or cysts in stool.
Disease: Bloating, flatulence, foul-smelling, fatty diarrhea.
Transmission: cysts in water

Answer 1

Giardia lamblia- Giardiasis

Question 2

Diagnosis: Oocyts on acid-fast stain.
Disease: Severe diarrhea in AIDS; Mild disease (watery diarrhea) in nonimmunocompromised.
Transmission: Oocysts in water
Treatment: Prevention by filtering H2O in city water supplies, treatment with nitazoxanide in immunocompetent hosts.

Answer 2

Cryptosporidium

Question 3

Diagnosis: Serology, biopsy (tachyzoite)
Disease: Brain abscess in HIV (seen as ring-enhancing brain lesions on CT/MRI); congenital **=classic triad of chorioretinitis, hydrocephalus, and intracranial calcifications.
Transmission: cysts in meat or oocyts in cat feces; crosses placenta.
What is the organism and the treatment?

Answer 3

Toxoplasma gondii
*toxoplasmosis

Treatment: Sulfadiazine + pyrimethamine
And W/a CD4+ <100 - TMP-SMX

Question 4

Diagnosis: Ameobas in spinal fluid.
Disease: rapidly fatal meningoencephalitis
Transmission: Swimming in freshwater lakes containing the organism; enters via cribriform plate. What is the microorganism and the treatment?

Answer 4

Naegleria fowleri

Treatment: Amphotericin B has been effective for a few survivors.

Question 5

Diagnosis: Blood smear
Disease: African sleeping sickness: enlarged lymph nodes, recurring fever (due to antigenic variation), somnolence, coma
Transmission: Tsete fly, a painful bite
What is the microorganism and treatment?

Answer 5

Trypanosoma brucei

Treatment: Suramin for blood-borne disease or melarsoprol for CNS penetration

Question 6

Diagnosis: Blood smear, ring form, “Maltese cross”; PCR
Disease: Fever and hemolytic anemia; predominantly in NE and North central US; asplenia increases the risk of severe disease.
Transmission: Ixodes tick, same as Lyme disease-may coinfect human
What is the microorganism and treatment?

Answer 6

Babesia - Babesiosis

Treatment: Atovaquone + azithromycin

Question 7

Disease: fever, headache, anemia, splenomegaly. 48h-cycle: fever on first day and third day (thus 48h); dormant form in liver (hypnozoite).
Transmission: Mosquito (anopheles)
Treatment: Begin with chloroquine, which blocks **** heme polymerase + primaquine
Diagnosis: Blood smear, trophozoite ring form within RBC, schizont containing merozoites.

Answer 7

Plasmodium vivax/ ovale - Malaria

Question 8

Disease: fever, headache, anemia, splenomegaly. Severe, irregular fever patterns; parasitized RBCs occlude capillaries in brain, kidneys, lungs.
Transmission: Mosquito (anopheles)
Treatment: Begin with chloroquine, which blocks _________ heme polymerase, if resistant: use mefloquine or atovaquone/proguanil

Answer 8

Plasmodium falciparum- (May present cerebral malaria)

Question 9

Disease: fever, headache, anemia, splenomegaly, 72-hr cycle (quartan).
Transmission: Mosquito (anopheles)
Treatment: Begin with chloroquine, which blocks______ heme polymerase, if resistant: use mefloquine or atovaquone/proguanil
Diagnosis: Blood smear, trophozoite ring form within RBC, schizont containing merozoites.

Answer 9

Plasmodium malariae- malaria

Question 11

Diagnosis: Macrophages containing amastigotes
Disease: Kala-afar: spiking fevers, hepatosplenomegaly, pancytopenia
Transmission: Sandfly
What is the treatment?

Answer 11

Leishmania donovani

Treatment: Amphotericin B, sodium stibogluconate

Question 12

Diagnosis: Trophozoites (motile) on wet mount; strawberry cervix.
Disease: Foul-smelling, greenish discharge; itching and burning.
Transmission: Sexual (cannot exist outside human because it cannot form cysts).
Treatment: Metronidazole for Px and partner (prophylaxis).

Answer 12

Trichomonas vaginalis - causes vaginitis.

Question 13

Disease: intestinal infection causing perianal pruritus (diagnosed via the Scotch Tape test).
Transmission: Fecal-oral
What is the microorganism and treatment?

Answer 13

Enterobius vermicularis- pinworm

Treatment: Bendazoles or pyrantel pamoate

Question 14

Disease: intestinal infection, may cause obstruction at ileocecal valve, biliary obstruction, intestinal perforation, and migrates from nose/mouth.
Transmission: Fecal oral; eggs visible in feces under microscope
What is the microorganism and treatment? What complication can occur if larvae migrate to alveoli?

Answer 14

Ascaris lumbricoides- giant roundworm

Treatment: Bendazoles or pyrantel pamoate
Complication: Loeffler Syndrome (pulmonary eosinophilia)

Question 15

Disease: GI infection (duodenitis), pulmonary (causing dry cough, hemoptysis), and cutaneous pruritus.
Transmission: Larvae in soil penetrate the skin.
What is the microorganism and treatment?

Answer 15

Strongyloides stercoralis (threadworm)

Treatment: Ivermectin or bendazoles

Question 16

Disease: Intestinal infection causing anemia by sucking blood from intestinal wall
Transmission: Larvae penetrate skin from walking barefoot on sand or soil.
What is the microorganism and treatment?

Answer 16

Ancylostoma duodenale, Necantor americanus (hookworms).

Treatment: Bendazoles or pyrantel

Question 17

Disease: Hyperpigmented skin and river blindness, black skin nodules; allergic reaction to microfilaria possible.
Transmission: Female blackfly bite.
Treatment: Ivermectin

Answer 17

Onchocerca volvulus

Question 18

Disease: Swelling in skin, worm in conjunctiva
Transmission: Deer fly, horse fly, mango fly.
Treatment: Diethylcarbamazine

Answer 18

Loa Loa

Question 19

Disease: Blocks lymphatic vessels: elephantiasis; takes 9mo-1yr after bite to become symptomatic
Transmission: Female mosquito
Treatment: Diethylcarbamazine

Answer 19

Wuchereria bancrofti - elephantiasis

Question 20

Disease: Visceral larva migrans into blood—> inflammation of liver, eyes (visual impairment), CND seizures and coma, and myocarditis.
Transmission: Fecal-oral
what is the microorganism and treatment?

Answer 20

Toxocara canis

Treatment: Bendazoles

Question 21

Disease: Intestinal infection
Transmission: Ingestion of larvae encysted in undercooked pork.
Treatment: Praziquantel

Answer 21

Taenia solium - (tapeworms)

Question 22

Disease: Cysticercosis, neurocysticercosis - brain cysts, seizures.
Transmission: Ingestion of eggs
Treatment: Praziquantel; albendazole for neurocysticercosis

Answer 22

Taenia solium - (tapeworms)

Question 23

Disease: Vitamin B12 deficiency (tapeworm competes for B12 in intestine) –> anemia
Transmission: Ingestion of larvae from raw freshwater fish
Treatment: Praziquantel

Answer 23

Diphyllobothrium latum - (tapeworms)

Question 24

Disease: hydrated cysts in liver, causing anaphylaxis if antigens released (surgeons preinject with ethanol to kill cysts before removal).
Transmission: Ingestion of eggs from dog feces
Treatment: Albendazole

Answer 24

Echinococcus granulosus - cestodes (tapeworms)

Question 25

Disease: Liver and spleen granulomas, fibrosis, and inflammation. Chronic infection with ________ can lead to squamous cell carcinoma of the bladder (painless hematuria).
Transmission: snails are host; cercariae penetrate skin of humans.
Treatment: Praziquantel

Answer 25

S. Haematobium

Question 26

Disease: Biliary tract inflammation–> pigmented gallstones. Associated with Cholangiocarcinoma and biliary tract disease.
Transmission: undercooked fish
Treatment: Praziquantel

Answer 26

Clonorchis sinensis - Trematodes (flukes)

Question 28

Diagnosis: Blood smear
Disease: Dilated cardiomyopathy, megacolon, megaesophagus; predominantly in South America.
Transmission: Reduviid (“kissing bug”) feces, depos. in a painless bite.
What is the disease and treatment?

Answer 28

Trypanosoma cruzi - Chagas’ disease
Treatment: Benznidazole or nifurtimox
Benz with a FUR coat on!

Question 29

This associated parasite (trematodes-fluke) causes portal hypertension. Two different species; name them.

Answer 29

Schistosoma mansoni and Schistosoma japonicum

Question 30

What is the classic triad seen in the children of pregnant women infected with toxoplasma gondii?

Answer 30

Chorioretinitis
Hydrocephalus
And intracranial calcifications

Question 31

Disease: Liver and spleen granulomas, fibrosis, and inflammation. May lead to portal hypertension.
Morphologically, shows a lateral spine in the egg.

Answer 31

Schistosoma mansoni

Question 32

This parasite burrows into the stratum corneum. Pruritus worse at night, and serpigenous burrows are found between fingers and toes. What is the parasite and treatment?

Answer 32

Scabies - sarcoptes scabiei

Treatment with permethrin cream, oral ivermectin. Treat close contacts

Question 33

What causes these Rapid associations:

Vitamin B12 deficiency

Answer 33

Diphyllobothrium latum

Question 34

What causes these Rapid associations:

Biliary tract disease, cholangiocarcinoma

Answer 34

Clonorchis sinensis

Question 35

What causes these Rapid associations:

Iron deficiency anemia

Answer 35

Ancylostoma/Necantor

Question 36

What causes these Rapid associations:

Myalgia, fever, vomitting, periorbital edema

Answer 36

Trichinella spiralis