Protozoa

• Fecal/Oral Route
• NO intermediate host

• 1-Amoebae  -Move by pseudopods (cysts & trophs)
• 2-Ciliates - 
• 3-Flagellates

• Size is Critical:
• trophozoites <12μm
• Central karyosome (like E. histolytica)
• Uneven peripheral chromatin
• Cysts <10μm

• Trophozoite 15-25μm
• small central karyosome
• Fine evenly distributed chromatin
• Cysts 10-20μm 
• 4 mature nuclei
• cigar shaped chromatoidal bars

World wide

• Invasive intestinal/extraintestinal infection
• ~ Liver, lung, brain abscesses (extraintestinal)
• ~ Bloody stools

• Trophozoite: average 25μm (15-30μm possible)
• Large, Ecentric karyosome
• Coarse, uneven/dark solid chromatin ring
• Cytoplasm- purple with vacuoles

• Cyst: 
• Chromotoidal bars (if present) are splintered
• Mature - 8 nuclei

Troph: 5-12, large karyosome, no peripheral chrmatin, vacuolated cytoplasm

• Cyst: 5-12, oval/spherical
• up to 4 nuclei

Troph: 6-20, vacuolated cytoplasm, nucleaus, single karyosome with no peripheral chromatin.

cysts: 6-15, glycogen vacuole (bubble looking)

• Largest protozoa associated with humans
• Uncommon in US
• Only pathogenic ciliate
• Troph: oval with vacuoles in cytoplasm
• Cyst: 45-75um; 2 kidney shaped nuclei

Stain with idodine

• No Cyst form* Important 
• 50-80 bi-nucleated, 4-8 karyosomes, 5-12μm
• Food vacuoles in cytoplasm
• *carriers, can cause disease
• Trophs usually have 2 nucleus with fringed edge of flagelete

• Identification of cysts or trophozoites in feces, repeat sampling, duodenal fluid for trophs.
• EIA & IFA common

• Troph's: 15-18 x 5-10 μm
• 8 flagella & the ventral side is modified as a sucking disk.

Cyst's: 8-12 μm Oval & 4 Nuclei

Most common of all protozoa

• Seen in those camping/drinking from stream
• Symptoms vary, but diarrhea, abd pain, bloating, nausea, & vomiting, maladsorption

Incubatin 1 - 14 dyas

trophozoites are passed in the stool but don't survive. It is the cyst form that contaminates food & water

Keep specimen warm and wet.

Wet mount jerky motility

Culture availble takes up to 7 days

• Found in monkeys
• troph - pear shape
• cyst - lemon shpae

• Small flagellate, rarely encountered
• Warm & temerate climates
• Non pathogenic

• small flagellate 
• warm & temperate climates
• Non pathogenic

• Tissue parasite with sexual and asexual cycles
• Sexual: ingest oocysts
• Asexual: ingest tissue infected with sporzoites.
• Life cycle include invasion of mucosal epi's.

• Nosocomial infections
• immunocompromised: chronic, life threatening diarrhea

• Oocysts infective when passed.
• RED = Oocyst & green = yeast

Modified Ziehl Nielsen acid fast stain

• Direct Exam: Modified acid fast stain
• Mature oocyst 20-30μm with 2 sporocysts

Seen primarily in AIDS patients.

• Infection in small intestine
• Nepal, Pakistan, & India

• Vomiting, wt loss, explosive diarrhea, fever, myalgia, fatigue, or asymptomatic
• Self limiting 3-4 days

• Asexual/Sexual
• Merozoites are called Meronts
• Oocytsts: Sperical 8-10μm, mature have 2 sporocysts present

• Dx: Light microsocopy of stool or 
• Variable acid fast when stained by the modified Ziehl-Neelsen method

• phylum
• 1000 species
• 7 are human pathogens 
• (entercytozoon & entercephalitozoon)
• Obligate intracellular parasite
• Seen in AIDS patients
• Infects: eyes, DNS, GI
• Spores 1.5-3um & confused with yeast

• Disease primarily in immunocomp. opportunistic only
• Causes encephalitis 
• *Free living amoeba in water

• Enter through broken skin or repiratory tract (lungs or skin through blood to CNS)causing: 
• Granulomatous amebic encephalitis.
• Specimen: CSF

Direct exam for motile trophs,  single nuclei with large karyosome, or cysts have starylike edges

troph enter through olfactory (nose, mouth) causing: Acute primary amebic meningoencephalitis (PAM)

<10 days, death/coma

Dx: microscopic exam of CSF, wet mount may detect motile trophs.