Parasitology - Protozoa Flashcards
What are the 3 protozoan that infect the GI tract?
1) Giardia lamblia
2) Entamoaba histolytica
3) Cryptosporidium
What are the symptoms of Giardiasis?
Bloating, Flatulence, Foul-smelling + FATTY diarrhea
Who is Giardiasis seen in? What is it’s “street name”?
Campers/hikers; Beaver Fever
How is Giardia lamblia transmitted?
Cysts in water; animals (beavers) shit in the river, you drink the water down stream
How do you diagnose Giardia lamblia?
Trophozoits or cysts in stool
What is the treatment for Giardia lamblia?
Metronidazole
What are the symptoms of Amebiasis?
(Entamoaba histolytica) Amebiasis: BLOODY diarrhea (dysentery), liver abcess (w/ “anchovy paste” exudate), RUQ pain
What will histology show if a submucosal abscess of the colon ruptures in Amebiasis?
A flash-shaped ulcer
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)
How do you diagnose Amebiasis?
Serology and/or trophozoite (with RBC’s in the cytoplasm) or cysts (with up to 4 nuclei) in stool
Treatment for Amebiasis?
Metronidazole; use iodoquinol for asymptomatic cyst passers
What are the symptoms of a Cryptosporidium infection?
Severe diarrhea in AIDS Mild disease (WATERY diarrhea) in immunocompetent
How is Cryptosporidium transmitted?
Oocysts in water
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
How do you diagnose Cryptosporidium?
Oocysts on acid-fast stain
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
What are the 3 protozoan CNS infections?
1) Toxoplasma gondii
2) Naegleria fowleri
3) Trypanosoma brucei
What are the symptoms of Toxoplasma gondii infection?
Brain abscess in HIV (ring enhancing lesions on CT/MRI)
What are the symptoms of congenital toxoplasmosis? (another triad…)
“Classic triad” of
1) Chorioretinitis
2) Hydrocephalus
3) Intracranial calcifications
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)
How do you diagnose toxoplasmosis?
Serology, biopsy (see tachyzoite)
How do you treat toxoplasmosis?
Sulfadiazine + Pyrimethamine
What happens with a Naegleria fowleri infection?
Rapidly fatal meningoencephalitis
How is Naegleria fowleri transmitted?
By swimming in freshwater lakes
Nalgene bottle filled with Fresh Water contains Naegleria
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)