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Microbio:Protozoa
USMLE Step 1
Bug | Pathology |
---|---|
Plasmodium vivax | only attacks immature RBCs, + hypnozoites:stage that stay w/in host & start reproduction only after a longer phase of inactivity, also called dormozoites,cause malaria |
Plasmodium ovale | only attacks immature RBCs, + hypnozoites:stage that stay w/in host & start reproduction only after a longer phase of inactivity, also called dormozoites,cause malaria |
Plasmodium falciparum | infects RBCs of all ages & at all stages,more RBCs infected=occlusion of capillaries w/ RBC aggregates=hemorrhage & necrosis in many organs,including brain,cause cerebral malaria,'Black Water Fever'-urine dark due to hemoglobinuria,cause malaria |
Plasmodium malariae | only mature RBCs are infected,only one w/ 72 hr cycle,cause malaria |
Babesia | causes Babeiosis,malaria-like sxs,vector:Ixodes tick,range:NE US & Cali,dx:bld smear w/ trophozoites in RBCs occur in pairs & tetrads in Maltese cross formation |
Pneumocystis carinii, now termed Pneumocystis jiroveci known as a yeast-prior was thought to be a protozoan, note prophylax when CD < 200 & use methamidine Au 2 stain bronchial lavage | in horses,sheep,rodents;transmitted by inhalation;asx;cause diffuse interstitial pneumonia(PCP),in AIDS pt & premies,spread 2 liver,spleen & bone marrow,100% fatal w/o tx,sudden onset fever,cough & dyspnea,bilat rales & rhonchi,tx w/ TMP-SMX or dapsone |
Toxoplasma gondii (Toxoplamosis) | in cats;encephalitis:in immunocompromised cause brain abscess in HIV;congenital;acquired from contaminated food (cat feces or undercooked meat) or inhalation onto GI mucosa then swallowed;prophylax AIDS pts |
Leishmania donovani (visceral leishmaniasis) | vector:sandfly -> RES -> Kala-Azar (pancytopenia & splenomegaly) -> untx progress to GI bld,intermittent fever,weight loss,hyperpigmentation -> Black sickness;reservoir:dog,fox,rodent;100% M&M w/o tx |
Leishmania brasiliensis | causes Espundia -> mucocutaneous ulcers & destruction of nasal cartilage |
Leishmania mexicana (cutaneous leighmaniasis,'chicle ulcer') | red papule at bite site -> enlrges w/ satellite lesions -> ulcerate & coalesce,100% mortality w/o tx |
Leishmania tropica (cutaneous leishmaniasis,'oriental sore' or 'Delhi boil') | red papule at bite site -> enlrges w/ satellite lesions -> ulcerate & coalesce,100% mortality w/o tx |
Trypanosoma cruzi (Chagas Disease,American Trypanosomiasis) | Range:South America,Vector:reduviid bug (kissing bug),bite -> facial edema -> focal nodule -> can be asx or go onto invasion of myocytes & GI plexus -> arrhythmias or CHF or toxic megacolon or mega-esophagus w/ achalasia |
Trypanosoma brucei (subspecies gambiense) | vector:tse-tse fly;reservoir:humans;range:west Africa(waterways);trypanomast in2 skin via bite-bld-lymph-brain;1st:fever,2nd: lymphadenopathy,3rd:encephalopathy,sleep-wake cycle opposite of nml,mood changes,slurred speech,tremors,apathy,somnolence,coma |
Trypanosoma brucei (subspecies rhodesiense), note more severe b/c fatal w/in months | vector:tse-tse fly;reservoir:cattle;range:arid east Africa;trypanomast in2 skin via bite-bld-lymph-brain;1st:fever,2nd: lymphadenopathy,3rd:encephalopathy,sleep-wake cycle opposite of nml,mood changes,slurred speech,tremors,apathy,somnolence,coma |
Entamoeba histolytica (amebiasis), note kill w/ iodine & filters, no animal reservoir, dx by Ab detect or wet mount O&P | cyst=4 nuclei,disease spread via cyst,trophozoite classic amoeba shape,infects colon,cyst divide in2 8 trophozoite cause tear drop or flask-shaped ulcers in colon=bldy diarrhea,can enter portal vein 2 cause hepatic abscess,transmit fecal-PO or anal sex |
Giardia lamblia (giardiasis) | transmit:fecal-PO,reservoir:many mammals,cyst (4 nuclei),trophozoite:2 nuclei,4 pairs of flagella,infects small intestine,assoc w/ drinking stream H2O,non-bldy,FOUL-smelling diarrhea,dx:'string test' or modern method Giardia Ab or wet mount O&P |
Cryptosporidium | severe diarrhea in HIV vs mild watery diarrhea in non-HIV,transmit:fecal-PO from animals or humans,affect s.intestine,non-bldy diarrhea becomes problem b/c of dehydration & electrolyte balance,acquired through drinking public H2O/tap water,dx:acid fast |
Trichomonas vaginalis (STI called trichomoniasis) | vaginitis,foul-smelling greenish discharge,pruritis & burning,transmit sexually,no cyst,trophozoite:1 nucleus,4 flagella w/ undulating memebrane,pear shaped,dx:wet mount |
Naegleria fowleri | amoeba,acquired by swimming in freshH2O lakes in Southern US (both East & West),enters the nasal mucosa & passes thru cribriform plate,causes purulent meningoencephalitis that is RAPIDLY FATAL >_< |
Acanthamoeba castellanii | an amoeba,causes keratitis in healthy contact lens users |