Digeneans

Question 1

What is the tegument?

Answer 1

An outer layer that is the primary site of absorption, it provides 0 defense.

Question 2

What are the two suckers in adults?

Answer 2

Oral sucker (feeding) and ventral sucker (attachment and locomotion)

Question 3

Traits of Phylum Platyhelminthes

Answer 3

Dorso-ventral flattening, bilateral symmetry, no coelom, no anus, no circulatory.

Question 4

What is the cell used in the excretory system?

Answer 4

Flame Cell: has a central duct and excretory pore at the posterior end. Some species might have a small bladder

They are also osmoconformers.

Question 5

Schistosomes and Didymozodae have separate sexes… they are ____

Answer 5

Dioecious

Question 6

What are the pros and cons of self fertilization?

Answer 6

Pro: no need to find a mate, or allows procreation when in isolation

Con: loosing genetic diversity

Question 7

Flukes all share one intermidate host, what is it?

Answer 7

Snail, but the species of snail varies by species of fluke

Question 8

What are the 3 types of metacercaria classes

Answer 8

1. develops in/on vegetation or surface of shells

2/3. can biomagnify

Question 9

What are the two sites for nutrient uptake?

Answer 9

Tegument and gut. Tegument is the main location and the fluke can survive with the pharynx tied off closing the gut.

Question 10

Where does the fluke reprouduce?

Answer 10

Asexually reproduces in a mollusk/intermediate host and sexual reproduces in a vertebrate/definitive host.

Question 11

Explain a basic fluke life cycle

Answer 11

Egg(in feces) >travels via water> Snail(1st inter. host) > miracidia>Mother sporocysts>daughter sporocyst(asexual reproduction)>Rediae>cercariae (becomes free living) >encysts into metacercaria on vegetation or muscle in 2nd inter. host >gets consumed by definitive host> adult

Question 12

What is the life cycle of Fasciola hepatica?

Answer 12

egg > (in snail) > miracidium > sporocyst >rediae > Cercariae > (on plant) metacercariae > Sheep/cattle def. host (or human)

Question 13

What is fascioliasis?

Answer 13

Caused by liver flukes

Acute phase: fever, vomiting, and abdominal pain caused by migration of immature flukes through hepatic parenchyma

Chronic phase: caused by adult fluke in bile duct and causes gall bladder obstruction

Question 14

What is the life cycle of Dicrocoelium dendriticum?

Answer 14

Egg > (in snail) > miracidium > sporocysts > cercariae > (ant) metacercaria > def host ruminates

Question 15

What is the life cycle of Clonorchis sp?

Answer 15

egg > miracidium > (in snail) sporocysts > cercariae > (fish) > metacercariae > human def. host

Question 16

What is the life cycle of Paragonimus westermani? (Human lung fluke)

Answer 16

2nd inter host decapods

def host human in the lung

eggs get coughed up

Question 17

What are the four schistosomes that we covered that infect humans?

Answer 17

Schistosoma mansoni,
Schistosoma haematobium,
Schistosoma japonicum, and
Schistosoma intercalatum

Question 18

What are Schistosomes?

Answer 18

Blood flukes
Adults live in intestinal or bladder veins, dioecious, penetrate skin while free swimming cercariae:

Question 19

How do you treat a schistosome?

Answer 19

Praxiquantel

Question 20

What is being done to control schistosomes?

Answer 20

Education, chemotherapy, snail control, environmental management, sanitation, and water supply.

Question 21

Compare and contrast the distributions of S. mansoni,
S. haematobium,
S. japonicum, and
S. intercalatum

Answer 21

S. Mansoni: S American and S/C Africa and parts of Saudi Arabia in savanna/swamp

S. haematobium: S/C/W Africa in open savanna/swamps

S. japonicum:
parts of China and Asia

S. intercalatum
West Africa