Digeneans Flashcards
What is the tegument?
An outer layer that is the primary site of absorption, it provides 0 defense.
What are the two suckers in adults?
Oral sucker (feeding) and ventral sucker (attachment and locomotion)
Traits of Phylum Platyhelminthes
Dorso-ventral flattening, bilateral symmetry, no coelom, no anus, no circulatory.
What is the cell used in the excretory system?
Flame Cell: has a central duct and excretory pore at the posterior end. Some species might have a small bladder
They are also osmoconformers.
Schistosomes and Didymozodae have separate sexes… they are ____
Dioecious
What are the pros and cons of self fertilization?
Pro: no need to find a mate, or allows procreation when in isolation
Con: loosing genetic diversity
Flukes all share one intermidate host, what is it?
Snail, but the species of snail varies by species of fluke
What are the 3 types of metacercaria classes
- develops in/on vegetation or surface of shells
2/3. can biomagnify
What are the two sites for nutrient uptake?
Tegument and gut. Tegument is the main location and the fluke can survive with the pharynx tied off closing the gut.
Where does the fluke reprouduce?
Asexually reproduces in a mollusk/intermediate host and sexual reproduces in a vertebrate/definitive host.
Explain a basic fluke life cycle
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
What is the life cycle of Fasciola hepatica?
egg > (in snail) > miracidium > sporocyst >rediae > Cercariae > (on plant) metacercariae > Sheep/cattle def. host (or human)
What is fascioliasis?
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
What is the life cycle of Dicrocoelium dendriticum?
Egg > (in snail) > miracidium > sporocysts > cercariae > (ant) metacercaria > def host ruminates
What is the life cycle of Clonorchis sp?
egg > miracidium > (in snail) sporocysts > cercariae > (fish) > metacercariae > human def. host
What is the life cycle of Paragonimus westermani? (Human lung fluke)
2nd inter host decapods
def host human in the lung
eggs get coughed up
What are the four schistosomes that we covered that infect humans?
Schistosoma mansoni,
Schistosoma haematobium,
Schistosoma japonicum, and
Schistosoma intercalatum
What are Schistosomes?
Blood flukes
Adults live in intestinal or bladder veins, dioecious, penetrate skin while free swimming cercariae:
How do you treat a schistosome?
Praxiquantel
What is being done to control schistosomes?
Education, chemotherapy, snail control, environmental management, sanitation, and water supply.
Compare and contrast the distributions of S. mansoni,
S. haematobium,
S. japonicum, and
S. intercalatum
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
