test 2 liver flukes.

Question 1

What is the scientific name for liver flukes?

Answer 1

Fasciola hepatica

Question 2

Are the eggs of Fasciola hepatic operculated? Which flukes have operculated eggs and which ones dont?

Answer 2

Liver and intestinal flukes have operculated eggs. Blood flukes dont.

Question 3

Describe the lifecycle of Fasciola hepatica?

Answer 3

Unembroynated eggs are passed in the feces. They embroynate in the watere. Miracidium (plural miracidia) hatch from the egg and infects a snail. The miracidium becomes a sporocyst inside the snail. Inside the sporocyst many rediae develop. Within the rediae cercariae develop. The cercariae leave the snail, develop into metacercariae (the infective form). These are eaten by humans or some other animal where they encyst in the duodenum and then become adults in the biliary ducts. Eggs are passed into the stool with bile.

Question 4

What types of areas and people does F. hepatica infect?

Answer 4

about 2.4 million people are infected worldwide. prevelance is highest in areas where sheep and cattle are raised and people eat raw aquatic vegetables. needs temperate environment and slow moving or standing water to flourish.

Question 5

describe the acute phase of a F. hepatica infection.

Answer 5

Rarely seen in humans but occurs when a person ingests a large number of metacercariae.
person has a fever, tender hepatomegaly, and abdominal discomfort. caused by the migration of F. hepatica through liver parenchyma.

Question 6

Describe the chronic phase of F. hepatica infection.

Answer 6

Abdominal pain, tender hepatomegaly, and jaundice (due to bile duct being blocked). symptoms are due to adult parasites blocking bile duct and inflammation due to presence of adult worms and their metabolic waste products.
can lead to fibrosis of the liver (pipestem liver) and can eventually lead to cirrhosis and death. can cause symptoms for up t o 10 years

Question 7

What are two other types of liver flukes?

Answer 7

Fasciola gigantica and Fasciola magna

Question 8

What is the scientific name for intestinal flukes?

Answer 8

Fasciolopsis buski

Question 9

What is the difference in lifestyles of intestinal and liver flukes?

Answer 9

nothing, they are the same. only difference is the metacercariae encyst in the intestines and the adults attach to intestinal wall where they live.

Question 10

How long does Fasciolpsis buski live for?

Answer 10

adults live for one year

Question 11

What is the scientific name of the chinese (oriental) liver fluke? What is the lifecycle?

Answer 11

Clonorchis sinensis.
Embryonated eggs are passed in the feces. Eggs are eaten by a water snail. Inside the snail the miracidia develops into sporocysts which develop rediae and finally the rediae develop cercariae. the cercariae swim out of the snail and are eaten by a fish where they encyst in the skin or muscle. the fish is then eaten by a human and the cycle is completed. cercariae encyst in the duodenum and adults live in the biliary duct.

Question 12

How many chinese are infected with Clonorchis sinensis.

Answer 12

average of 14% in hong kong and as much as 80-100% of people living in rural villages.

Question 13

describe the eggs of Clonorchis sinensis.

Answer 13

oval shape. have the little “shoulder pads”.

Question 14

How long does Clonorchis sinensis live for? how many eggs can they produce per day?

Answer 14

can live up to 40 years. produce about 2400 eggs per day.

Question 15

What is the drug of choice for liver and intestinal flukes?

Answer 15

Praziquantel. Increases permeability of Ca ions causing the parasite to contract and become paralyzed.

Question 16

What are some of the potential problems related to liver fluke infection?

Answer 16

Cause erosion of epithelium lining, inflammation, and fibrosis. Eggs are often trapped in the liver tissues and granulomas to form around them. granulomas can in turn block bile ducts which causes jaundice.
20-200 is a normal infection although up to 21000 have been found in a single liver.

Question 17

What is the scientific name for the lung fluke?

Answer 17

Paragonimus westermani.

Question 18

Describe the lifecycle of Paragonimus westermani.

Answer 18

same as liver fluke except cercariae invade crustaceans and encyst into metacercariae. Humans get the infection by eating raw or undercooked crustaceans.

Question 19

How does Paragonimus westermani get to the lungs?

Answer 19

Metacercariae encyst in the duodenum, penetrate through the intestinal wall into the peritoneal cavity. They then migrate through the abdominal wall and diaphragm into the lungs where they develop into adults.

Question 20

Will Paragonimus westermani always get to the lungs?

Answer 20

sometimes the worms can get into striated muscle and the brain.

Question 21

are P. westermani always alone?

Answer 21

No, alot of the time they are found in pairs even though they are hermaphroditic. There are often 2 to a cyst in the lungs.

Question 22

What are some of the symptoms of a P. westermani infection?

Answer 22

Pleurisy, pneumothorax, bad cough, bronchitis, blood in sputum, mild anemia, and weariness. Many times its confused with tuberculosis or pneumonia.

Question 23

Describe extrapulmonary Paragonimiasis.

Answer 23

caused by ectopic parasites in strange locations.can be in the abdominal wall or in the brain. can cause diarrhea and abdominal pain if in GI tract to visual disturbances, headaches and epilepsy if in the brain.

Question 24

What is needed for the diagnosis of a liver fluke infection?

Answer 24

have to see eggs in sputum or stool. also must have history of exposure such as travel to endemic areas, or consumption of undercooked seafood. ELISA is also commonly used.

Question 25

What is unique about Dicrocoelium dendriticum?

Answer 25

Infects ants. causes them to get on top of blades of grass so theyre eaten by cows to complete the lifecycle.