METAZOANS (Trematodes/ LIVER FLUKES)

Question 1

True or False

Trematodes are heteroxenous and man is the definitive host of all

Answer 1

True

Question 2

True or False

All trematode egg are operculated except blood flukes

Answer 2

True

Question 3

Trematode spp egg stage (immature when passed out):

Answer 3

• Fasciola hepatica
• Fasciolopsis buski
• Echinostoma ilocanum
• Paragonimus westermani

mnemonic: “FFEP”

Question 4

Trematode spp egg stage (mature when passed out)

Answer 4

• Clonorchis sinensis
• Heterophyes heterophyes
• Opistorchis felineus
• Metagonimus yokogawai
• Dicrocoeulum dendriticum
• Schistosoma species

Question 5

Enumerate trematode stages in order:

Answer 5

1. Egg stage
2. Miracidium
3. Sporocysts
4. Redia
5. Cercaria
6. Metacercaria
7. Adult

Question 6

Trematode stage; Free-swimming ciliated larval stage, pyriform in shape, secretory glands —> enzymes for penetration of snail tissue

Answer 6

Miracidium

Question 7

Trematode stage; Saclike, serves as brood sac for the development and production of redia

Answer 7

Sporocysts

Question 8

Trematode stage; Daughter sporocysts (larva produced within sporocysts)

Answer 8

Redia

Question 9

Trematode stage; Free-swimming larva stage with a tail; lophocercus (simple or keel-tailed) or microcercus

Answer 9

Cercaria

Question 10

Encysted cercaria:

Answer 10

Metacercaria

Question 11

Liver flukes
Habitat:
MOT:

Answer 11

Liver flukes
Habitat: Intrahepatic bile duct
MOT: Ingestion of encysted metacercaria in infected 2nd intermediate host

Question 12

Common name/ other name of Fasciola hepatica:

Answer 12

Sheep liver fluke
Temperate fluke

Question 13

Common name/ other name of Clonorchis sinensis:

Answer 13

Oriental liver fluke
Chinese liver fluke

Question 14

Common name/ other name of Opistorchis felineus & viverrini

Answer 14

Cat liver fluke
Southeast Asian liver fluke

Question 15

Common name/ other name of Dicrocoelium dendriticum

Answer 15

Lancet liver fluke

Question 16

Identify:
Egg: hen’s egg with flat operculum
Adult: Leaf-shaped with branched ceca, with shoulder

Answer 16

Fasciola hepatica

Question 17

Identify:
Egg: Old fashioned electric bulb
Adult: Bottle-neck appearance

Answer 17

Clonorchis sinensis

Question 18

Identify;
Adult: Resembles C. sinensis but narrow and smaller,. Egg is practically similar

Answer 18

Opistorchis felineus & viverrini

Question 19

Identify;
Egg: Asymmetrically ovoid with broad convex operculum
Adult: lancet-shaped; testes obliquely anterior to ovary

Answer 19

Dicrocoelium dendriticum

Question 20

First intermediate host of liver flukes:

Answer 20

Snails (vary in species)

Question 21

Snail species of the first intermediate host of F. hepatica;

Answer 21

Lymnaea

Question 22

Snail species of the first intermediate host of Opistorchis felineus & viverrini:

Answer 22

Bethynia

Question 23

Snail species of the first intermediate host of Dicrocoelium dendriticum;

Answer 23

Zebrina
Helicella
Cionella

Question 24

Second intermediate host of Fasciola hepatica:

Answer 24

Aquatic plants
- Ipomoea obscura (Kangkong)
- Nasturtium officinale (watercress)

Question 25

Second intermediate host of Clonorchis sinensis and Opistorchis felineus & viverrini:

Answer 25

Fish
- Cyprinidae (Carp/minnow)

Question 26

Second intermediate host of Dicrocoelium dendriticum:

Answer 26

Ants
- Formica fusca (Silky ant)

Question 27

Disease caused by Fasciola hepatica:

Answer 27

• Liver rot
• Halzoun

Question 28

Disease caused by Clonorchis sinensis and Opistorchis felineus & viverrini:

Answer 28

• Cholangitis: Bile duct
• Cholecystitis: Galbladder
• Cholangiocarcinoma - Cancer (bile duct)

Question 29

Disease caused by Dicrocoelium dendriticum:

Answer 29

• Hyperplasia of biliary epithelium

Question 30

Also known as “Tropical liver fluke”

Answer 30

Fasciola gigantica