PMMV unit #1.1

single celled parasites of medical importance

protozoa and sporozoan

multicelled organisms of medical importance

helminths

protozoan parasites are classified according to their

motility organelles

amoeba move by

pseudopodia (false feet)

flagellates move by

flagella

ciliates move by

cilia

sporozoa are

nonmotile

helminths are classified according to their

shape

two types of flatworms

flukes(trematodes) and tapeworms (cestodes)

roundworms

nematodes

protozoa

unicellular eukaryotes

Trophozoite

the active, motile, and feeding stage of protozoa inside the host

cyst

the hard, safe shell that helps the parasite survive outside the body

Cestodes (tapeworms/segmented)

elongated and segmented worms that are hermaphroditic with various larval stages

trematode (flukes/flatworms)

nonsegmented and hermaphroditic worms containing intestines and tissues with a complex life cycle

snails are included in what helminth category

trematodes (flukes/flatworms)

nematodes (roundworms)

roundworms with separte sexes, well developed digestive systems, and have humans as the definitive host

nematodes (roundoworm) life cycle

adult female produces fertilized eggs or larvae that hatch and infect host

oocyte

type of cyst formed after sexual reproduction in certain protozoa

egg

the reproductive cell produced by worms or flukes

larvae

the early, immature worm stage that hatches from an egg

Microfilaria

a tiny baby roundworm found in blood or skin

sheath

a tiny protective cover found on some microfilariae

Hexacanth larva

a six hooked embryo inside certain tapeworm eggs

scolex

head of tapeworm with hooks and suckers

rostellum

tiny pointed nose or crown on a tapeworm head

proglottids

the repeating egg making body segments of a tapeworm

heraphrodite

an organism that has both male and female reproductive organs

brood capsule

small pocket inside cyst that makes baby tapeworm heads

hydatid cyst or sand

large fluid filled cyst cyst containing loose tapeworm heads

uterine branches

the egg tubes inside a tapeworm segment used to identify species

rhabditiform

the first non-infective feeding stage of certain roundworm larvae

filariform

the long, slender, infectious second stage of roundworm larvae

miracidium

the first swimming baby stage of a fluke (trematode)

coracidium

the free swimming baby stage of specific tapeworms

cercaria

the tadpole-like swimming stage of a fluke (trematode)

schizont

a cell stage that divides into many little parasites

sporogony

making infectious spores through sexual through sexual reproduction

schizogony

making new parasites through asexual multiple splitting

merozites

tiny new parasites made during a schizont split

gametocyte

the male or female sec cell of a malaria parasite

Schüffners dots

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

Maurers clefts

large coarse irregular dot structures seen inside rbcs infected with specific malaria parasites that resemble schuffners dots

undulating membrane

a wavy fin-like edge used for swimming by some flagellates

Karyosome

a dense dot of dna inside a nucleus

peripheral chromatin

dna chunks clustered near edge of nucleus

axostyle

stiff rod running down the middle of certain flagellates

kinetoplast

a special dna mass inside the mitochondrion of specific flagellates

axoneme

the core hair-like thread inside a flagellum or cilium

flame cell

a tiny cup-shaped cell used by flatworms to get rid of waste

parabasal body

a golgi-like body next to the nucleus in some flagellates

chromatoid body

a dark rod or clump of stored material inside protozoan cysts

glycogen vacuole

a clear space storing sugar inside a cyst

operculum

a cover or lid on the end of certain fluke eggs

Abopercular knob

a small bump or hook-like point on the opposite end of the operculum on an egg, hatch point

shoulder

a small ridge where the operculum meets the egg shell

corticate/mammilate

a rough and bumpy outer coating on a roundworm egg

definitive host

organism in which a parasite matures and reproduces

intermediate host

temporary organism where a parasite grows, develops into an immature or larval stage, or reproduces asexually

accidental host

organism that is not the normal or preferred host of a parasite

vector

a living carrier, like an insect or tick, that transmits disease-causing parasites from one host to another

reservoir

a host or place where a parasite lives and multiplies long term

adult parasite

location of the parasite stage in a human host

diagnostic stage

the means by which parasite stages leave the human

infective stage

when the parasite is infective

parasite life cycle

adult parasite in small intestine, fertilized female lays eggs, diagnostic stage (eggs in feces), infective stage, method of infection, larvae hatch out of egg shell in intestine

Two-vial transport system

two sealed vials with specific volume needed that are used for two different tests

traditional process for optimal detection of parasites

series of three stool specimens collected a day or two apart within a 10 day period

current method for parasite detection

pooling of three formalin preserved specimens

con of using three formalin preserved specimens

if parasites are not present in large numbers, they may be missed microscopically because of dilution effect upon pooling

if the first test is negative for parasites and the patient remains symptomatic, what type of test is done

examine a second or third specimen

fecal specimens for parasitic testing should never be collected from what and why

bedpans or toilet bowls because of risk of contaminating sampel with free living protozoa, urine, or water

alternative specimen collection procedures

place specimen on wax paper or newspaper and transfer to container, use disposable collection container (hat) that can be fitted under toilet bowl

what is the ratio of preservative to feces required for optimal parasite fixation

3:1

polyvinyl alcohol

common fecal sample preservative that is used for permanently stained smear and dna-pcr

10% formalin is used for what lab exam methods on fecal samples

formalin-ethyl acetate concentration, direct wet mount, immunoassays

Sodium acetate-acetic acid formalin (SAF) is used for what lab exam methods on fecal samples

permanently stained smears and concentration

Merthiolate-iodine-formalin (MIF) is used for what lab exam methods on fecal samples

concentration and direct wet mount

single vial systems are used for what lab exam methods on fecal samples

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

diagnostic and therapeutic compounds inside patients that are interfering in fecal samples

barium/bismuth, mineral oil/castor oil, Abx and anti-darrheal drugs, metamucil

external collection contaminants in fecal samples

water, urine, toilet paper

pseudoparasites

organism that is not parasitic but mistaken for one

fecal specimen types of testing

macroscopic exam, microscopic exam, fecal concentration, permanent staining,

macroscopic exam of fecal specimen

examine unpreserved stool for consistency, color, and intact worms or proglottids seen on surface of stool

liquid stools suggest a ___ number of cysts and a ___ number of trophozoites

low, high

formed stool specimens have a ___ number of cysts and a __ number of trophozoites

high, low

liquid stools should be examined within ___ minutes of passage to detect motile trophozoites morphologic forms of some parasites

30

formed stool should be examined within _ to _ hours of passage if help at room temp or __ hours at 4C

2-3, 24

a stool specimen should never be placed in a ___ _______ because it increases the rate if disintegration of any organisms present and enhances overgrowth by bacteria

37C incubator

folowing macroscopic evaluation, a stool specimen should be placed in to the appropriate ____ for concetration and preparation of permanently stained smear

fixative

two types of concentration techniques

sedimentation and zinc sulfate flotation

Sedimentation

formalin-ethyl acetate method to recover all ova, cysts, and larvae into a concentrated pellet at bottom of tube

What form of parasite does not get recovered through sedimentation

trophozoite

parasite concentration methods concentrate the parasite based on

differences in specific gravity between parasites and concentrating solution

Zinc Sulfate Flotation

delicate protozoan cysts will float in zinc sulfate solutions of high osmolality and specimens can be collected onto a glass slide

cons to Zinc Sulfate Flotation

distorts the cysts slightly and does not capture heavy eggs

direct mount exam/wet prep

microscopic exam used to detect motile protozoan trophozoites, cysts, helminth eggs, and larvae using one drop of saline and one drop of iodine mixed with specimen and covered with glass slide

iodine prep is used to look for

nuclear detail within cell and glycogen masses/vacuoles

iodine kills what stage of protozoa

trophozoites

saline prep is used to look for

helminth eggs or larvae, motile protozoa, and refractive protozoan cysts