Demonstration Sheets for Adult Trematodes (Lab 2)
Phylum Platyhelminthes, Class Trematoda, Subclass Digenea, Family Schistosomatidae
Schistosoma japonicum
Members of this family are unusual in the Digenea because the sexes are
separate. The male has a split body which is wrapped around the female in the definitive
host. Depending on the species, members of this genus live in veins draining the
intestines or the urinary bladder of humans. See figures 16.5, 16.6, & 16.7; pp 252-53.
P5 1525, Dissecting scope
Phylum Platyhelminthes, Class Trematoda, Subclass Digenea, Family Schistosomatidae
Schistosoma
This is a cross-section through the intestine of an infected mouse showing the
worms in the small veins that absorb nutrients from the lumen. These vessels are a
component of the hepatic portal system. The male is wrapped around the female and the
image is similar to looking at the end of a hotdog after a couple of bites.
10X & 40X, 92W 5159
Phylum Platyhelminthes, Class Trematoda, Subclass Digenea, Family Schistosomatidae
Schistosoma mansoni egg
The presence of a single spine is a characteristic of the schistosome ovum.
Spines appear at different places on ova of different schistosome species. See Fig. 16.8,
p. 254.
92W 5167, 40X
Healthy (= uninfected) human liver tissue
Carolina 5400, 10X
Phylum Platyhelminthes, Class Trematoda, Subclass Digenea, Family Schistosomatidae
Schistosoma mansoni
Eggs in liver are being destroyed by host leukocytes. The immune system forms
a granuloma (visible on slide as a ring) around the egg. In some victims the granulomas
develop to the point where they restrict blood flow through the liver. In extreme cases,
the eggs pass through the liver and lodge in the lungs. See Figures 3.8 (p. 35) and 16.15
& 16.16 (pp. 258- 59)
PS 1308, 10X-40X
Phylum Platyhelminthes, Class Trematoda, Subclass Digenea
Fasciola
Sheep liver fluke. Adults are found in bile ducts of humans and herbivores.
Infective metacercariae are found on leaves of plants.
Figs. 17.4 & 17.5 (pp 268 & 270)
Specimen and slides (= PS 1250), No scope
Phylum Platyhelminthes, Class Trematoda, Subclass Digenea
Paragonimus westermani
Lung fluke Adults of this genus are found in the lungs of carnivores including
humans and cats. Ova are carried out of the lungs by cilia on the epithelial cells lining
the trachea. The ova are swallowed when they reach the pharynx, pass through the gut,
and are voided in host feces. Acquired by eating uncooked crustaceans. See Figs. 18.7
& 18.8 (pp. 281-282)
Specimen & slide (= 92W PS 1414), Dissecting
Phylum Platyhelminthes, Class Trematoda, Subclass Digenea
Dicrocoelium
See Figs. 18.1 & 18.2 (pp. 278-79), Be able to identify: 1. Testes (purple stain, large), 2.
Ovaries (purple stain, small), 3. Uterus (black), 4. Acetabulum, 5. Oral sucker
Tropical Biological, Dissecting
Phylum Platyhelminthes, Class Trematoda, Subclass Digenea
Eurytrema
Genus occurs in the pancreas of raccoons and domestic animals. Insects such
as grasshoppers serve as second intermediate hosts. “Dr” Hulda Clarke makes the
following claims about this trematode: 1. Causes diabetes, 2. Epstein-Barre virus comes
from the fluke. 3. Drinks with wood alcohol enable the fluke access to the pancreas. 4.
The fluke can enter the uterine wall and cause endometriosis.
Carolina 30-6388 (PS1340), Dissecting
Phylum Platyhelminthes, Class Trematoda, Subclass Digenea
Trematode Model
Use Fig. 18.18 (pp. 287) for help in identifying: Oral sucker, Pharynx, Intestine,
Acetabulum, Vitellaria or yolk gland, Uterus, Ovary, Testes, Excretory bladder
Phylum Platyhelminthes, Class Trematoda, Subclass Digenea
Clonorchis sinensis
Chinese liver fluke. Same species as the one on the model. Very common in
rural Asian communities. Acquired by eating raw freshwater fish, especially carp.
Z950, 4X
Phylum Platyhelminthes, Class Trematoda, Subclass Digenea
Nasitrema
This genus is found in the nasal cavities of whales and dolphins. These
specimens were taken from a female bottlenose dolphin that was found dead in Mobile
Bay. The presence of parasites in beached marine mammals does not mean that the
death or the beaching behavior was caused by the parasite.
Specimen, Dissecting
Phylum Platyhelminthes, Class Trematoda, Subclass Digenea
Hirudinella ventricosa
Collected from the stomach of a wahoo (a bluewater game fish) caught during
the Dauphin Island Fish Rodeo. For reasons unknown, usually two and only two worms
are found in the stomachs of wahoos.
Specimen, No scope