fall pmmv week 1

significance

cause morbidity and mortality, GI blood tissue infections, immunocomp become susceptible, world travel, immigrants with endemic parasites, climate change

phyla

parasitic agents in single celled org (protozoa, sporozoan), multicelled org (helminth worm)

protozoan motility

classified according to motility organelles, ameba pseudopodia (false feet), flagellates flagella, ciliates cilia, sporozoa nonmotile

prorozoa

unicellular, eukaryotic, trophozoite (motile, feeding, multiply), cyst (immotile, protected by cell wall, infective for humans, becomes troph)

helminth cestodes (tape/seg)

elongates segmented ribbon like, hermaphroditic (m/f), various larval stages

helminth trematodes (flukes/flat)

non seg, intestines/tissues, hermaphroditic, complex life cycle- snails

helminth nematodes (round)

separate sexes, developed digestive system, humans are host, female produces fertilized eggs or larvae

egg

reproductive cell produced by worms of flukes

larvae

early immature worm stage that hatches from an egg

microfilaria

tiny baby roundworm in blood or skin

sheath

tiny cover found on some microfilaria

hexacanth larva

six hooked embryo inside certain tapeworm eggs

oocyst

cyst after sexual reproduction

scolex

the head of a tape worm with hooks and suckers

rostellum

tiny pointed nose or crown on a tapeworm head

proglottids

repeating egg making body segments of a tapeworm

hermaphrodite

animal with both male and female sex organs

brood capsule

small pocket inside a cyst making baby tapeworm heads

hydatid cyst or sand

large fluid filled cyst containing tiny loose tapeworm heads

uterine branches

egg tubes inside a tapeworm segment used to identify species

rhabditiform

first, non infective feeding stage of certain roundworm larvae

filariform

long slender, infectious second stage of roundworm larvae

miracidium

first swimming baby stage of a trematode fluke

coracidium

free swimming baby stage of specific tapeworms

cercaria

tadpole like swimming stage of a trematode fluke

schizont

cell stage that divides into many little parasites

sporogony

making infectious spores through sexual reproduction

schizogony

making many new parasites through asexual multiple splitting

merozoites

tiny new parasites made during a schizont split

gametocyte

male or female sex cell of a malaria parasite

schuffner’s dots

small brick red uniform dots of protein seen inside rbc infected with specific malaria parasites

maurer’s clefts

large coarse irregular dot structures seen inside rbcs infected with specific malaria parasites

undulating membrane

wavy fin like edge used for swimming by some flagellates

karyosome

dense dot of dna inside a nucleus

peripheral chromatin

dna chunks clustered near the edge of the nucleus

axostyle

a stiff rod running down the middle of certain flagellates

kinetoplast

a special dna mass inside the mitochondrion of specific flagellates

axoneme

core hair like thread inside a flagellum or cilium

flame cell

tiny cup shaped cell used by flatworms to remove waste

parabasal body

golgi like body next to the nucleus in some flagellates

operculum

cover or lid on the end of certain fluke eggs

abopercular knob

small bump or hook like point on the opposute end of the operculum on an egg, hatch point

shoulder

small ridge where the operculum meets the egg shell

corticate/mammilate

rough bumpy outer coating on a roundworm egg

definitive host

org where parasite matures and reproduces sexually

intermediate host

temp org where parasite grows into immuature or larval stage, or reproduces asexually

Reservoir host

An animal that harbors a parasite that can also infect humans

accidental host

org not normal or preferred host

adult

location of parasite stage in human host

diagnostic stage

how parasite leaves the human (in feces)

fecal oral route

person to person (direct), food, water, encysted larvae in meat/fish

risk factors

political/social climate (3rd world, refuge), behavioral patterns, immunocomp (AIDS, transplant, lymohoma, cancers)

fecal collection

series of 3 collections a day or 2 apart within 10 days, time consuming labor intens

pooling 3 formalin preserved spec yields the same recovery rate, saves time, could miss small number para

2 or 3 only if 1st is neg and pt is symptomatic

alt specimen collection

place on waxed paped or newspaper transfer to container (not bedpans or toilet), disposable collection container (hat) fitted under toilet bowl

fecal preservatives

3:1 preservative to feces

polyvinyl alc

permanently stained smear, DNA-PCR

10% formalin

formalin-ethyl acetate concentration, direct wet mount, immunoassays for histology, acid-fast

sodium acetate-acetic acid formalin

permanently stained smears and concentration, acid-fast

merthiolate-iodine-formalin

concentration and dorect wet mount

single vial systems

concentration, direct we mount, permanently stained smears, and immunoassays

interfering subs

Barium/Bismuth (radio image/ stom meds), Mineral Oil/Castor Oil (resemble cysts), Abx- Anti-Diarrheal drugs (suppress recovery), Metamucil (dilutes specimen), pseudoparasites, water, tp, urine

macroscopic exam

unpreserved stool checking for intact worms, proglottids on the surface, blood, mucus; liquid soft formed specimen, put in fixative and concentrate after

liquid stool

examine within 30 min to detect motile trophozoites forms, lowest amount of cysts most trophozoites

formed stool

examine within 2-3 hrs if rt, 24hrs if 4 C, most cysts least trophozoites

sedimentation concentration tech

formalin-ethyl acetate FES method, recover all ova cysts and larvae, not trophozoite forms, pellit

zinc sulfate flotation concentration tech

preserves delicate protozoan cysts, less fecal debris, distorts cysts slightly but preserves them, but heavy eggs will not float, at top

direct wet mount

saline (cysts, helminth eggs and larvae, motility) and/or iodine (nuclear detail, glycogen masses/vacuoles), battlement low and high objectives, note parasitic and artifact forms

ocular micrometer calibration

measures structures aiding in parasite ID, nuclear detail, glycogen masses/vacuoles

permanent staining techs

wheatleys trichrome stain (fresh fixed stool or PVA preserved, intestinal protozoa RED, less time consuming, most used) and iron hematoxylin stain (SAF preserved)

cellophane tape prep

pinworms (enterobius vermicularis), tape against butthole before child wakes then place on slide

agar plate culture

strongyloides stercoralis, tiny track migration crawl of larvae, low level infec, formalin to collect for microscopic exam ID

entero test

duodenal aspirates, looks for eggs oosyts of fasciola hepatica and clonorchis sinensis, recover oocysts of cryptosporidium and C. belli, swallow pile attached to string on cheek

urine sediment is screened for

schistosoma haematobium eggs, E. vermicularis eggs, trichomonas vaginalis trophozoites

vaginal wet preps or urethral dischrage screens for

trichomonas vaginalis trophozoites

sputum screens for

Strongyloides stercoralis, Ascaris lumbricoides, Hookworm, Paragonimus westermani

lower resp tract screens for

Entamoeba histolytica, Cryptosporidium oocysts, Microsporidia

calcofluor white staining

sticks to cell wall glows under UV light, Microsporidia, Acanthamoeba, Naegleria, Balamuthia

auramine O

acid fast glow green or yellow fluor light, Cryptosporidium, Cystoisospora belli, Toxoplasma

modified acid-fast stain

Cryptosporidium, Cystoisospora, and Cyclospora, magenta

giemsa stain

gold standard for blood and intracellular, Thick and thin blood smear preparation for malaria parasites

whole blood smears vs buffy coat

finger stick (malaria), EDTA (must be under 1 hr, can use wrieght stain bc less time consuming), Plasmodium, Babesia, Trypanosoma, some microfilaria

cytoplasm of monocytes= Leishmania, Toxoplasma gondii

blood ID procedure thick film

no fix needed, Giemsa stain (releases hgb by lysing rbcs, visible- wbc plt parasites), set for 6 hrs, 100x-1000x

blood ID procedure thin film

methanol fixed, Giemsa stain (treat like a diff), parasitemia (% of erythocytes paracited) count 500+ rbcs, species ID 100x-1000x, more specific

parasitemia calculation

# of infected rbcs / total # of rbcs counted x100= % of infected rbcs

CSF tests for

amebic meningitis- sleeping sickness, trypomastigote, naegleria fowleri (culture with e. coli, look for thin tracks)

biopsy

histology area, tissue sections stained and examined, amastigote form, Trichinella spiralis, Toxoplasma gondii

tissue parasites stimulate

ab production, can use serological tests

enzyme immunoassays EIA

ag detection kits instead of microscopic, Giardia duodenalis, Cryptosporidium, Entamoeba histolytica, Entamoeba dispar, Plasmodium spp

fluorescent ab techs (direct DFA)

apple green, high sensitivity and specificity, Cryptosporidium, Giardia duodenalis, Malarial organisms – Acridine orange

Toxoplasmosis and Entamoeba histolytica tests

commerically immunoassays

molecular testing

PCR and real time PCR, multiplex PCR (GI), rapid no processing, if neg and symptomatic pt investigate

micrometer calibration

stage micrometer- 0.1 mm line ruled in 0.01-mm units

ocular micrometer- ruled in 100 units but has no values

Charcot-Leyden crystals are occasionally observed in stool. These crystals are probably from breakdown products of:

eosinophils