Demonstration Sheets for Filarial Nematodes & Acanthocephalans (Lab 5)
Page Numbers are from 8th ed of Roberts & Janovy
Phylum Nematoda
Enterobius vermicularis
Eggs
Female worms emerge from the rectum during the night and lay their eggs
around the anus. Eggs can be detected by microscopic examination of Scotch Tape®
that had been placed with the sticky side down, on the anal area. See Fig 27.5 (p. 449)
Wards 92W 5693, 10X
Phylum Nematoda, Order Oxyurida
Enterobius vermicularis
Adult & Pinworm
Body cavity is filled with eggs. The pointed tail is responsible for the common
name. See Fig. 27.4, p. 449
92W 5695, 4X
Phylum Nematoda, Order Oxyurida
Enterobius vermicularis
Adult % Pinworm
The tails of males are shorter and more curved than those of females. The mouth
and esophageal bulb are easy to recognize. See Fig. 27.1 (p. 448)
Trop. Biol. E. vermicularis male, 10X
Phylum Nematoda, Superfamily Filaroidea
Wucheria bancrofti
Elephantiasis
This specimen is an advanced embryo or MICROFILARIAL LARVA. The surface
is covered with a thin layer of epidermal cells in which the nuclei are well-stained. This
is the stage that infects the mosquito. See Fig. 29.3 (p. 465).
Tropical Biological, 40X
Phylum Nematoda, Superfamily Filaroidea
Onchocercerca volvulus
River Blindness
Adults live in subcutaneous connective tissue where they are found in nodules.
This slide is a section through such a nodule and shows cross-sections of the adult
worms. See Fig. 29.5 (p. 468). Examine the slide under both 4X and 10X lenses to
acquire a good perspective of the sample.
Tropical Biological, 4 X – 10X
Phylum Nematoda, Superfamily Filaroidea
Dirofilaria immitis
Dog Heartworm
This is the MICROFILARIAL LARVA stage that is transmitted to mosquitoes. As
with the Wucheria example, the nuclei of the surface cells on the microfilaria stain very
well.
CBS Z 1020, 40X
Phylum Nematoda, Superfamily Filaroidea
Dirofilaria immitis
Dog Heartworm
Adult worms are usually found in the right atrium, right ventricle, and pulmonary
artery of dogs. The worms may lodge in the lungs of hosts after they die causing
extensive damage. The most effective treatment is to destroy the infective larval stages
before they become adults.
Specimen
Phylum Acanthocephala
Macracanthorhynchus
This slide is a cross-section of the pig’s intestine showing the positioning of
structures of the cephalic region of the worm imbedded in host tissue. See
accompanying diagram and Fig. 32.13 (p 506)
PS 2600, Dissecting scope
Phylum Acanthocephala
Macracanthorhynchus hirudinaceus
This large acanthocephalan (The specimen is broken into two parts) parasitizes
pigs throughout the world. Pigs acquire the parasite by eating scarab beetle (larvae or
adults) containing the infective cystacanth stage.
Specimen
Phylum Arthropoda, Class Insecta, Order Coleoptera
Scarab Beetle
Species of scarab beetles feed on dung, carrion, and decomposing vegetation
and are likely to be on pig farms where they can serve as intermediate hosts for
Macracanthorhynchus hirudinaceus.
Specimen
Phylum Acanthocephala
Eggs
Eggs of acanthocephalans can be recognized by the three concentric rings in the
shell coating. The egg contains an acanthor larva. See Fig. 32.10a (p. 504)
PS 2620, 10X
Phylum Acanthocephala
Adult Male and Female
Be able to recognize the sex of the specimens as well as the anterior from the
posterior ends. See Figure 32.3 (p 498).
CBS PS 2652, Dissecting scope
Phylum Acanthocephala
Worms are embedded in the intestinal tissue of a bluegill (fish) taken from the
Causeway in Mobile Bay.)
Specimen, Dissecting scope
Phylum Acanthocephala
Observe the spines on the proboscis. This structure is characteristic of the
phylum. The specimen was taken from a gar caught in the Mobile Delta. (You will not
be responsible for this latter piece of information.)