Parasitology - Protozoa Flashcards by Logan Adams

What are the 3 protozoan that infect the GI tract?

1) Giardia lamblia
2) Entamoaba histolytica
3) Cryptosporidium

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What are the symptoms of Giardiasis?

Bloating, Flatulence, Foul-smelling + FATTY diarrhea

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Who is Giardiasis seen in? What is it’s “street name”?

Campers/hikers; Beaver Fever

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How is Giardia lamblia transmitted?

Cysts in water; animals (beavers) shit in the river, you drink the water down stream

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How do you diagnose Giardia lamblia?

Trophozoits or cysts in stool

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What is the treatment for Giardia lamblia?

Metronidazole

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What are the symptoms of Amebiasis?

(Entamoaba histolytica) Amebiasis: BLOODY diarrhea (dysentery), liver abcess (w/ “anchovy paste” exudate), RUQ pain

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What will histology show if a submucosal abscess of the colon ruptures in Amebiasis?

A flash-shaped ulcer

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How is Entamoeba histolytica transmitted?

Cysts in water (active trophozoite found only in host and fresh feces; cysts live outside host in water, soil, and food - especially in moist conditions)

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How do you diagnose Amebiasis?

Serology and/or trophozoite (with RBC’s in the cytoplasm) or cysts (with up to 4 nuclei) in stool

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Treatment for Amebiasis?

Metronidazole; use iodoquinol for asymptomatic cyst passers

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What are the symptoms of a Cryptosporidium infection?

Severe diarrhea in AIDS
Mild disease (WATERY diarrhea) in immunocompetent

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How is Cryptosporidium transmitted?

Oocysts in water

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What is unique about Cryptosporidium lifecycle?

Does not need to use an insect host and can complete an entire lifecycle inside a single host which results in cyst stages that are excreted and can be transmitted to a new host

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How do you diagnose Cryptosporidium?

Oocysts on acid-fast stain

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What is the treatment for a Cryptosporidium infection?

Mainly symptomatic (hydration therapy, electrolyte management, pain management, etc.)
Prevent by filtering city water supplies
Use Nitazoxanide in immunocompetent patients

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What are the 3 protozoan CNS infections?

1) Toxoplasma gondii
2) Naegleria fowleri
3) Trypanosoma brucei

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What are the symptoms of Toxoplasma gondii infection?

Brain abscess in HIV (ring enhancing lesions on CT/MRI)

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What are the symptoms of congenital toxoplasmosis? (another triad…)

“Classic triad” of

1) Chorioretinitis
2) Hydrocephalus
3) Intracranial calcifications

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How is toxoplasmosis transmitted?

Cysts in meat or oocysts in cat feces;
Crosses placenta (classic presentation is a pregnant woman who is taking care of a cat)

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How do you diagnose toxoplasmosis?

Serology, biopsy (see tachyzoite)

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How do you treat toxoplasmosis?

Sulfadiazine + Pyrimethamine

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What happens with a Naegleria fowleri infection?

Rapidly fatal meningoencephalitis

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How is Naegleria fowleri transmitted?

By swimming in freshwater lakes

Nalgene bottle filled with Fresh Water contains Naegleria

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What part of the body does Naegleria fowleri enter through?

Cribiform plate

How do you diagnose a Naegleria fowleri infection?

Amoebas in spinal fluid

How do you treat Naegleria fowleri?

Amphotericin B (effective for few)

What is a Trypanosoma brucei infection called?

African Sleeping Sickness

What are they symptoms of African Sleeping Sickness (T. Brucei)?

Enlarged LNs, recurring fever, somnolence, coma

How does T. Brucei cause recurring fever?

Antigenic Variation

What are the two subspecies of T. Brucei?

Rhodesiense | Gambiense

What is the difference between Rhodensinse and Gambiense?

Rhodesience - fast onset/acute; most common in southern and eastern africa = game animal and livestock reservoir Gambiense - slow onset/chronic; most common in central and western africa = human reservoir

How is T. Brucei transmitted?

Tsetse fly, painful bite

How do you diagnose african sleeping sickness?

Blood smear

How do you treat African Sleeping Sickness?

SURamin for blood-borne disease MELArsoprol for CNS penetration (It SURe is nice to go to sleep; MELAtonin helps with sleep)

What are the 2 hematologic parasitic infections?

Plasmodium and Babesia

What are the subtypes of Plasmodium?

P. Vivax/Ovale P. Falciparum P. malariae

What are the symptoms of malaria?

Fever, headache, anemia, splenomegaly

What are the symptoms of a P. vivax/ovale infection? Where does it lie dormant?

48 hr cycle = tertain = fever on first and third day so fevers are 48 hours apart; lies dormant in liver (hypnozoite form)

What are the symptoms of a P. Falciparum infection?

Severe, irregular fever patterns, parasitized RBC's occlude capillaries in the brain (cerebral malaria), kidneys, and lungs

What are the symptoms of a P. malariae infection?

Runs on a quartan (72hr) cycle with fevers

How is Plasmodium transmitted?

Mosquito

How do you diagnose Plasmodium infections?

Blood smear, trophozoite ring form within RBC (banana shaped thing) Schizont containing merozoites

How do you treat malaria?

Begin with Chloroquine (blocks Plasmodium heme polymerase)

How do you treat malaria resistant to chloroquine?

Mefloquine or Atovaquone/Proguanil

How do you treat a life threatening malaria infection?

IV Quinidine

African American male that has a history of a splenomegaly, back pain, and hemoglobinuria. You go to start him on IV quinidine for his life-threatening malaria infection when a smarter doctor (someone who got a 260 on boards) stops you and tells you that you can't because he has a genetic condition. What condition? What will you see on a blood smear? And how is it inherited?

G6PD deficiency Heinz bodies and bite cells X-linked recessive

What do you treat Vivax/Ovale with?

Add Primaquine for hypnozoite in liver (also need to check for G6PD here)

What are the symptoms of Babesiosis?

Fever and hemolytic anemia

Where is Babesia found? (geographic and animal)

Predominately in the NE US in the Ixodes Tick

What else besides Babesia does the Ixodes tick carry?

B. Burgorferi (Lyme Disease); they can coinfect

What increases the risk of a Babesia infection?

Asplenia

What will be seen on blood smear with Babesiosis? What else can you do to diagnose?

A ring form, "maltese cross"; PCR

What is treatment for Babesiosis?

Atovaquone + Azithromycin

What are the visceral and STD protozoal infections?

1) T. Cruzi (Visceral) 2) Leishmania donavani (Visceral) 3) Trichomonas Vaginalis (STD)

What is the result of a T. Cruzi infection?

Chagas disease

What are the symptoms of T. Cruzi?

Everything gets BIG! Cardiomyopathy Megacolon Megaesophagus (achalasia)

Where is T. Cruzi found?

South America

What transmits T. Cruzi?

Reduvidd bug (kissing); feces deposited in a painless bite

How do you diagnose T. Cruzi?

Blood smear

What is the treatment for T. Cruzi?

Benznidazole or Nifurtimox

What are the symptoms of Leishmaniasis?

A.K.A. (Kala-Azar): Spiking fevers, hepatosplenomegaly, Pancytopenia

How is Leishmania transmitted?

Sandfly

How do you diagnose Leishmania?

Macrophages containing amastigotes

What is the treatment for Leishmania?

Amphotericen B, Sodium Stibogluconate

What does Trichomonas Vaginalis cause? Symptoms?

Vaginitis; foul smelling greenish discharge; itching and burning (Not the same as Gardnerella Vaginalis = bacterial vaginosis = fishy smell + clue cells)

How is Trich transmitted?

Sexual (can't form cysts so it can't go anywhere else)

How do you diagnose Trich?

Trophozoites (motile) on a wet mount; "strawberry cervix"

What is the treatment for Trich?

Metronidazole for patient and partner (prophylaxis)