Protozoa Flashcards
(33 cards)
Giardia lamblia
Protozoa
Disease: Giardiasis - bloating, flatulence, foul-smelling, fatty diarrhea (often in hikers, day care, mental hospitals) “fat-rich Ghirardelli chocolates for fatty stools of Giardia”
*predisposition with IgA deficiency
Transmission: cysts in water, infects small intestine
Diagnosis: Trophozoites or cysts in stool
Treatment: Metronidazole
Entamoeba histolytica
Protozoa
Disease: Amebiasis - bloody diarrhea, liver abscess (“anchovy paste” exudate), RUQ pain, histology shows flask-shaped ulcer
Transmission: cysts in water
Diagnosis: serology and/or trophozoites (with RBCs in cytosol) or cysts (w up to 4 nuclei) in stool
Treatment: Metronidazole, iodoquinol for asymptomatic
Cryptosporidium
Protozoa
Disease: Severe diarrhea in AIDS patients, mild watery diarrhea in healthy, associated with outbreaks of diarrhea in water supply
Transmission: oocytes in water
Diagnosis: oocysts on acid fast stain
Biopsy: basophilic clusters on surface of intestinal mucosal cells
Treatment: prevention, nitazoxanide in immunocompetent
Toxoplasma gondii
Protozoa
Disease: congenital toxoplasmosis (TORCH infection) = triad of chorioretinitis, hydrocephalus, intracranial calcifications
reactivation in AIDS= brain abscess as ring-enhancing lesion on CT/MRI
Transmission: cysts in meat, oocysts in cat feces; cross placenta-avoid cats
Diagnosis: serology, biopsy (tachyzoite)
Treatment: sulfadiazine + pyrimethamine
Naegleria fowleri
Protozoa
Disease: rapidly fatal meningoencephalitis
Transmission: swimming in freshwater lakes; enters cribiform plate
Diagnosis: amoebas in CSF
Treatment: Amphotericin B, still very fatal even with treatment
Trypanosoma brucei
Protozoa
Disease: African sleeping sickness- LAD, recurring fever, somnolence, coma, encephalitis
Transmission: Tsetse fly, painful bite
Diagnosis: blood smear
Treatment: Suramin for blood borne disease, add Melarsoprol for CNS penetration
Plasmodium
Protozoa
Disease: Malaria - fever, HA, anemia, splomegaly
P vivax/ovale- 48hr cycle (tertian fever on 1st and 3rd day); dormant form (hypnozoite) in liver, binds duffy antigen on RBCs (often absent on blacks) - treat with primaquine
P. falciparum - severe; irregular daily fever patterns; parasitized RBCs occlude capillaries in brain, kidneys, lungs
P. malariae- 72 hr cycle (quartan)
Transmission: Anopheles mosquito
Diagnosis: blood smear: trophozoite ring within RBC, schizont containing merozoites; red granules (Schuffner stippling) throughout RBC cytoplasm in P. vivax/ovale
Treatment: chloroquine (blocks plasmodium heme polymerase), mefloquine if resistant
if life threatening-> IV quinidine or artesunate
Add primaquine for hypnozoite in P. vivax/ovale
Babesia
Protozoa
Disease: Babesiosis- fever and hemolytic anemia, infects and reproduces in RBCs-> lysis
Transmission: Ixodes tick (can be co-infected w borellia) - predominantly in NE U.S.; asplenia increases risk of disease
Diagnosis: blood smear: ring form, “Maltese cross”; PCR
Treatment: Atovaquone + azithromycin
Trypanosoma cruzi
Flagellated protzoa
Disease: Chagas disease- chronic phase-> dilated cardiomyopathy w apical atrophy, megacolon (damage of Auerbach’s plexus-> loss of inervation -> loss of tone), megaesophagus, *unilateral preorbial swelling (Romana sign) characteristic of acute stage
Transmission: Reduviid bug “kissing bug” feces then painless bite - predominantly in S. America, scratching facilitates penetration
Diagnosis: blood smear
Treatment: Benznidazole or nifurtimox
Leishmania donovani
Protozoa
Disease: Visceral leishmaniasis- spiking fevers, HSM, pancytopenia
Transmission: sandfly
Diagnosis: Macrophages containing amastigotes
Treatment: Amphotericin B, sodium stibogluconate, oral miltefosine
Trichomonas vaginalis
Protozoa
Disease: Vaginitis - foul-smelling, greenish discharge, itching and burning
(don’t confuse with gardnerella vaginalis which has grey fishy smelling discharge, non-painful)
Transmission: Sexual (cannot exist outside humans, can’t form cysts)
Diagnosis: “strawberry cervix” Trophozoites (corkscrew motility) on wet mount
Treatment: Metronidazole for patient and partner (prophylaxis)
Eterobius vermicularis (pinworm)
Nematode (roundworm)
Disease: Intestinal infection, anal pruritis
Transmission: Fecal-oral
Diagnosis: seeing egg via tape test
Treatment: Bendazoles (worms are bendy!), pyrantel pamoate
Ascaris lumbricoides (giant roundworm)
Nematode (roundworm)
Disease: Intestinal infection w possible obstruction at ileocecal valve
Transmission: fecal-oral
Diagnosis: eggs visible in feces under microscope
Treatment: Bendazoles (worms are bendy!)
Strongyloides stercoralis
Nematode (roundworm)
Disease: Intestinal infection- vomiting, diarrhea, epigastric pain, Loffler’s syndrome (pulm eosinophilia), dermatitis; can become disseminated disease in immunosuppressed
Transmission: larvae in soil penetrate skin
Treatment: Ivermectin or bendazoles
Ancylostoma, duodenale, Necator americanus (hookworms)
Nematode (roundworm)
Disease: intestinal infection -> anemia, sucks blood from intestinal walls (Big teeth!)
Transmission: larvae penetrate skin
Treatment: Bendazoles or pyrantel pamoate
Trichinella spiralis
Nematode (roundworm)
Disease: larvae enter blood and encyst in striated muscle cells -> muscle inflammation. Trichinosis- fever, vomiting, periorbital edema, myalgia
Transmission: fecal-oral, undercooked meat esp pork
Treatment: Bendazoles
Onchocerca volvulus
Nematode (roundworm)
Disease: Hyperpigmented skin and river blindness (black flies, black skin nodules, black sight); allergic rxn to microfilaria possible
Transmission: Female blackfly bite
Treatment: Ivermectin
Loa loa
Nematode (roundworm)
Disease: Calabar swelling in skin (localized tense inflammatory edema in joints), worm in conjuctiva!
Transmission: Deer fly, horse fly, mango fly
Treatment: diethylcarbamazine
Wuchereria bancrofti
Nematode (roundworm)
Disease: Elephantiasis - worms block lymphatic vessels, takes 9mo-1yr after bite to have symptoms
Transmission: female mosquito
Treatment: diethylcarbamazine
Toxocara canis
Nematode (roundworm) - usually in dogs and cats
Disease: visceral larva migrans
Transmission: fecal-oral
Treatment: Bendazoles
Taenia solium
Cestodes (tapeworm)
Transmission and disease:
-ingestion of larvae in undercooked pork -> Taeniasis: intestinal infection, can be asymmtomatic or GI upset
-ingestion of taenia solium eggs -> cysticercosis (cysts found in skin, muscles or CNS), neurocysticercosis -> seizures
Treatment: Praziquantel, albendazole for neurocysticercosis
Diphyllobothrium latum
Cestodes (tapeworm)
Disease: B12 deficiency (tapeworm competes) -> megaloblastic anemia (can take years to see symptoms bc large B12 stores)
Transmission: ingestion of larvae from raw freshwater fish
Treatment: Praziquantel
Echinococcus granulosus
Cestodes (tapeworm)
Disease: Hydatid cysts in liver (filled with clear fluid w Abs), causes anaphylaxis if antigens released
Transmission: Ingestion of eggs from dog feces, sheep are intermediate host
Treatment: Albendazole, surgical removal of cyst
Schistosoma
Trematodes (flukes)
Disease: “Swimmer’s itch” ,
Intense immune response-> cell infiltrant-> granulomas, inflammation and fibrosis
Intestinal disease
-Hepatosplenic granuloma, Liver and spleen enlargement, fibrosis and inflammation (S. mansoni, egg w lateral spine) -> portal HTN
-Chronic infection with S. haematobium (egg w terminal spine) -> squamous cell carcinoma of bladder (painless hematuria) and pulmonary HTN
Transmission: Snails are host; cercariae penetrate skin of humans
Diagnosis: antigens via ELISA
Treatment: Praziquantel
