Intro, Amoeba, Flagellates, Cilliates

1. one collected every other day
2. within no more than 10 days
3. one collected after true laxatives

1. formalin
2. SAF
3. total-fix

good overall fixative
long shelf life
conc sediment can be used with diff stains and immunoassays

doesn’t preserve trophozoites
doesn’t work with perm stains
not appropriate for molecular dx

does not contain mercury
conc sediment can be used with diff stains and immunoassays
can be used for stool conc and perm smear

poor adhesive properties (needs albumin slides for perm smears)
trichrome stain does not work well with SAF (iron hematoxylin is better)
more difficult to use

non-mercury, non-formalin, non-PVA fixative
can be used for perm smear and conc technique, can perform most IA
single vial

inconsistent results

Hg-PVA
modified PVA
total fix

can prepare perm stain smear
great to preserve protozoan trophozoites/cysts
organism morph great
suitable for DNA-PCR analysis

contains mercury
cannot be used with IA
may turn gelatinous if refrigerated/dehydrated

mercury is replaced with copper or zinc
can prepare perm smear

overall protozoan morph is inconsistent
organism ID may be difficult compared to Hg-PVA

1. direct wet mount
2. concentrated
3. perm stain smear

0.85% saline
Lugol's or D'Antoni's iodine

1. formalin ethyl acetate sedimentation
2. zinc sulfate flotation

1. trichome
2. iron hematoxylin

separates eggs and protozoan cysts from excess debris.
Uses liquid with high spec gravity. Surface film and sediment examined

adv: less fecal debris in wet mount
disadv: loss of some helminth eggs (esp heavy and operculated eggs)

adv: all parasites in sediment, less technical error
disadv: more debris

Giardia lamblia
Entamoeba coli
Iodamoeba buetschlii

best with PVA fixed specimens
easy to perform staining
flexible timing

intestinal protozoa, human cells, yeast cells, and artifacts

helminth eggs and larvae

adv: good with PVA or SAF fixed specimens
disadv: more difficult staining, critical timing

indicates inflammation
may be mistaken for amebic cysts

indicates mucosal ulceration or other hemorrhagic problems
may/not be related to parasitic infection

eosinophils indicate immune resp
may/not be related to parasitic infection
CLC are disintegrated eosinophils

Entamoeba histolytica
Entamoeba dispar
Entamoeba hartmanni
Entamoeba coli
Endolimax nana
Iodamoeba buetschlii
Dientamoeba fragilis
Blastocystis species

fecal oral

amebic dysentery

tropics and subtropics (over than in cooler climates)

Intestinal--Lumenal
Extraintestinal (2-8%) (invasion of intestinal mucosa, can spread to heart brain lungs)

O&P
PCR
E. histolytica antigen test

sigmoidoscopy
serology
stain aspirate for organisms (find troph)

R upper quad pain and tenderness
abscess of radiologic scan
if undetected can lead to lungs, heart, skin, brain

PATHOGENIC

15-20 microns
(range 10-60 microns)

single nucleus
compact central karyosome
even peripheral chromatin
*ingested RBC is diagnostic

no more than 4 nuclei
rounded chromatoidal bars may be present

nonpathogenic

E histolytica (cannot be diff using morph)

nonpathogenic

5-12 microns

single nucleus
compact central karyosome
even peripheral chromatin
*RBC NOT ingested

5-10 microns
spherical
1-4 nuclei
blunt rounded chromatoidal bars may be present

nonpathogenic

15-50 microns
single nucleus
uneven peripheral chromatin
large diffuse off center karyosome
ingests bacteria and other debris

>5 nuclei
chromatoidal bars with splintered ends
staining quality variable
easier to ID on wet mount

nonpathogenic

bacteria

6-12 microns
single nucleus
large karyosome, nuclear variation (reddish)
no peripheral chromatin

5-10 microns
spherical and ellipsoidal
4 large nuclei with no peripheral chromatin
nuclei not visible in unstained wet mount (may be visible with iodine)

nonpathogenic

bacteria

8-20 microns
single nucleus
large karyosome, basket nucleus
no peripheral chromatin

5-20 microns
oval to round
single nucleus
large compact glycogen vacuole present

PATHOGENIC

children

unknown

Dientamoeba fragilis

5-15 microns length, 9-12 microns width
shaped like amoeba
1-2 fragmented nuclei (tetrad)
no peripheral chromatin

permanent stain smear mandatory to detect trophozoites

possibly.
Pathogen?

watery diarrhea, abdom pain, asymptomatic

6-40 microns
central body form
large central mass surrounded by small mult nuclei
quantitate organism when reporting

Giardia duodenalis (lamblia)
Chilomastix mesnili
Pentratrichomonas (trichomonas hominis)

asymptomatic to severe diarrhea;
diarrhea, abdom pain, bloating, nausea, vomiting

children or in groups that live in close quarters
outbreaks: poor sanitation, backpackers, travel

waterborne
fecal oral
ingestion of infective cysts
(contam water, food, or hands with infective cysts)

PATHOGENIC

10-20 microns length; 9-12 microns width
teardrop shaped
2 nuclei, ventral sucking disk, 4 pairs flagella, 2 axonemes, 2 med bodies

round/oval
11-14 microns length, 7-10 microns width
shrunken/distorted when stained (halo effect)
4 nuclei, 4 axonemes, 4 med bodies

O&P (conc wet, perm stain)
immuno assay (DFA, EIA, IC)
can be found in duodenal contents

nonpathogenic

6-24 mi length, 4-8 mi width
single nucleus adjacent to oral groove or cytostome
3 ant flagella, 1 posterior

6-10 mi length, 4-6 mi width
lemon shaped
single nucleus
curved cystostomal fibril shaped like shepherds crook

nonpathogenic

pentratrichomonas

5-15 mi length, 7-10 mi wide
pyriform shape with axostyle and undulating membrane that extends entire length of organisms
costa

Balantioides coli

PATHOGENIC

lives in large intestines,
widely distributed in hogs (reservoir hosts)

50-100 microns, large ovoid
cytostome present
kidney bean macronucleus

diarrhea, nausea, dysentery
troph invades colonic mucosa and can cause tremendous fluid loss similar to cholera