Important points to remember for parasites

Entameoba histolytica

think of RBCs+BLOOD+LIVER

-pathogenic

-amebic dysentery

-bloody/mucous diarrhea

-trophozoites may contain ingested RBCS

- can cause liver abscess

-cyst= important transmission stage

-trophozoite= active/invasive stage

Entameoba coli

think of BIG+MESSY

- nonpathogenic

-larger than e.histolytica

-junky cytoplasm

-multiple pseudopods

-up to 8 nuclei in cyst

-frayed chromatoidal bar ends

endolimax nana

think of BALL IN SOCKET

- small

- no peripheral chromatin

-large karyosome

- "ball in socket"

- up to 4 nuclei in cyst

iodamoeba butschlii

think of IODONE+GLYCOGEN

-large glycogen vacuole

-iodine=reddish brown appearance

-no chromatoidal bars

giardia lamblia

think of TWO EYES+SUCTION CUP+FALLING LEAF

-two nuclei

-ventral sucking disk

-falling leaf motility

-greasy foul smelling diarrhea

-associated with contaminated water

-cyst is hardy and important in transmission

naegleria fowleri

think of NOSE=BRAIN=FAST

- warm/brackish/ water exposure

- enters through the nose

-travels along olfactory nerve

- primary amebic meningoencephalitis (PAM)

-rapidly progressive

-trophozoites can be found CNF

-brain eating ameba

acanthamoeba

think of CONTACT LENS+EYE+SPINES

-contact lens associated keratitis

-can cause granulomatous amebic encephalitis (GAE)

-chronic/insidious disease

-trophozoites have spiny pseudopods ( acanthopodia)

- cysts has a double wall

balantidium coli

think of BIGGEST+CILIA+PIG

-only pathogenic human ciliate

-largest protozoan parasite

-covered in cilia

-swine=natural host

-humans=accidental host

-cyst= infective stage

trichomonas vaginalis

think SEXUAL+NO CYST

-urogenital pathogen

-sexuallly transmitted

-pear shaped

-four anterior flagella

-undulating membrane

-no cyst stage

dientsmeoba fragilis

think of DI=TWO

-usually 2 nuclei

- 5-12 micrometers

-weakly staining

- no cysts stage identified

leishmania

sandfly=vector

sandfly=infects human

promastigote=infective stage

amastigote= diagnostic stage in human

leishmania amastigote

inside macrophages

• small

• oval

• intracellular

• large nucleus

• rodlike kinetoplast

leishmania tropica

think of: TROPICA=tropical skin sore

old world cutaneous leishmaniasis/oriental sore

leishmania mexicana

cutaneous + new world

think of: MEXICANA-mexico-new world lesion

leishmania braziliensis

mucocutaneous

think of:BRAZILIENSIS-brazil-mucosa-skin-oral/nasal mucosa-cartilage destruction

leishmania donovani

VISCERAL

think: DONOVANI= doesn’t stay on the skin

it spreads to the reticuloendothelial system affects the liver, spleen, bone marrow

major clues: fever+weight loss+ hepatomegaly+ splenomegaly

t.brucei

african sleeping sickness

think brucei=brain

first is lymphatic disease- CNS disease-sleeping-coma

vector=tsetse fly

t.brucei diagnostic specimen

look for trypomastigotes in

• blood

• lymphatic fluid

• CSF

t.cruzi

chagas disease

think:cruzi=cardiac+GI

chronic disease can cause

• myocarditis

• heart failure

• megaesophagus

• megacolon

toxoplasma gondii

cat=definitive host

human=intermediate host

transmission’

• oocysts from cat feces

• undercooked meat containing cysts

• congenital transmission

• organ transplant/blood transfusion

remember

• tachyzoite=active, invasion form

• bradyzoite= dormant form inside tissue cysts

  
  

diagnosis= primarily serology

cognital= PCR of amniotic fluid

cyclospora cayetanensis

think: 8-10 micrometers

autofluorescence

• food/waterborne

• tropical/subtropical

• spherical

• variable acid fast staining

• bright blue/mint green autofluorescence

cryptosporidium

think:tiny+ watera+watery diarrhea

• 4-6 micrometers

• round/slightly oval

• modified acid fast positive

• oocyst identified in stool

• waterborne outbreaks

• severe prolonged disease in immunocompromised patients

cystoisospora belli

think: big oval+ two sporophytes

• mature oocyst= 2 sporocysts

• stool specimen

• acid fast stain or wet mount

• more severe in immunocompromised patients

plasmodium

tranmission

• female anopheles mosquito

• infectie stage to humans= sporozoite

• diagnostic stages= trphozoite,shizont,merozoite

• human=intermediate hots

• mosquito definitive host

diagnosis

• thick smear= screen

• thin smear=speciate

• giemsa stained blood smear

• collect during/ around paroxysm

• examine multiple smears if necessary

babesia

think of: tick-RBC-ring-maltesse cross

• vector-ixodes tick

• reservoirs=mice and deer

• b.microti=most common species

• infective stage=sporozoite

• diagnostic stage=trophozoite

• blood smears shows small ring forms

• maltese cross=tetrad

• causes hemolytic anemia

• rbcs are not enlarged

• no malarial pigment

• no malarial paroxysm

p.vivas

enlarged RBC+shuffners’s dots+16 merozoites

p.malariae

band form+ziemann’s dots+ 8 merozoites

p.ovale

oval RBC schuffner’s dots+6-12 merozoites

p.falciparum

multiple rings+2 chromatin dots+ applique forms+bana gametocytes