PMMV Unit #1.1

Protozoa

classified by their motility: ameba (psuedopodia), flagellates (flagella), ciliates (cilia), Sporozoa (nomotile)

Hemlinth

classified by shape. Flatworms (trematodes and cestodes) and roundworms (nematodes)

Trophozoite

The active, moving, and feeding stage inside the host

Cyst

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

Oocyst

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 the blood or skin.

Sheath

A tiny protective cover found on some microfilariae.

Hexacanth larva

A six-hooked embryo inside certain tapeworm eggs.

Scolex

The head of a tapeworm with hooks and suckers.

Rostellum

The tiny pointed nose or crown on a tapeworm head.

Proglottids

The repeating egg-making body segments of a tapeworm.

Hermaphrodite

An animal that has both male and female sex organs.

Brood capsule

A small pocket inside a cyst that makes baby tapeworm heads.

Hydatid cyst or sand

A large fluid-filled cyst containing tiny 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 (trematode) fluke.

Coracidium

The free-swimming baby stage of specific tapeworms.

Cercaria

The tadpole-like swimming stage of a (trematode) fluke.

Schizont

A 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

The tiny new parasites made during a schizont split.

Gametocyte

The male or female sex cell of a malaria parasite.

Schüffner’s dots

Small brick red uniform dots of protein seen inside red blood cells infected with specific malaria parasites.

Maurer’s clefts

Large, coarse, irregular, dot structures seen inside RBCs infected with specific

malaria parasites. Resemble Schüffner’s dots.

Undulating membrane

A wavy fin-like edge used for swimming by some flagellates.

Nucleus

The control center of the cell holding DNA.

Karyosome

A 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

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 (kidney-like).

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, bumpy outer coating on a roundworm egg.

Definitive Host

Organism in which a parasite matures and reproduces sexually.

Intermediate Host

Temporary organism where a parasite grows, develops into an immature or larval stage, or reproduces asexually. (Pass through)

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

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.

Method of Infection

The means by which a new human host is infected (e.g., egg is ingested).

Stool Specimen

deliver to lab ASAP or placed in preservative. Traditionally 3 stool specimen over 10 day period.

Formalin Preserved Stool

risks that small number parasites get diluted out. 3:1 ratio of preservative to feces

Diagnostic/Theraputic Interfering Substances

barium/bismuth, mineral oil/castor oil, anitbiotics/anti-diarrheal drug, metamucil

Macroscopic Exam

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

Formed Stool Storage

examine within 2 to 3 hours at RT. Can store at 4C for 24hrs

Sedimentation

formalin-ethyl acetate method. recovers all ova, cysts, and larvae. no trophozoites

Zinc Sulfate Flotation

preserves delicate protozoan cysts. distorts them slightly, does not capture heavy eggs

Microscopic Exam

saline/iodine. Battlement method

Ocular Micrometer Calibration

required for measuring structures to aid in id of parasties

Trichrome Stain (w/Wheatly Modification)

fresh stool fixed, or preserved in PVA acceptable. intestinal protozoa

Iron hematoxylin Stain

specimen preserved in SAF

Entero-Test

duodenal aspirates. looks for eggs of fasciola hepatica and clonorchis sinensis. Can recover oocysts of cryptosproidium and C. belli