Exam I - Alaria spp

Question 1

Give the common name for Alaria spp

Answer 1

Intestinal flukes

Question 2

What is/are the final host(s) for Alaria spp?

Answer 2

dogs, cats, foxes, minks, wild boar, raccoon, and opossum

Question 3

What is/are the intermediate host(s) for Alaria spp?

Answer 3

freshwater snails and frogs (tadpoles)

Question 4

What is/are the paratenic host(s) for Alaria spp?

Answer 4

frogs, snakes, mice, rats, birds, and other small mammals (racoons, opossums), reptiles, and humans

Question 5

Decribe the appearance of Alaria spp adult

Answer 5

Adults ~ 10 mm, pink or brown, with oral and ventral suckers and a cylindrical hind-part

Question 6

Describe the appearance of Alaria spp eggs

Answer 6

Oval, honey color, 130 um, medium thick shell, operculum distinct

Question 7

What is a miracidia

Answer 7

free swimming, cliated larvae

Question 8

What is a cercariae?

Answer 8

tadpole-like larvae, final and free swimming

Question 9

What is a metacercariae?

Answer 9

encysted resting or mature stage of a trematode - Stage right before they parasitize a host

Question 10

Describe the life cycle of Alaria spp

Answer 10

• Final host passes eggs in feces, which hatch in water.
• Miracidia emerge, penetrate the snail, and emerge as cercaria
• Cercariae encyst in frogs as mesocercariae
• A paratenic host becomes infected after ingesting an infected tadpole
• When the dog or cat ingests the 2nd intermediate host or paratenic host, the mesocercariae is liberated, penetrates the gut wall, migrates to the lungs to develop to a juvenile fluke
• The juvenile fluke migrates up the trachea, is swallowed and matures in the small intestine. PPP is 5 weeks

Question 11

What is the PPP for Alaria spp?

Answer 11

5 weeks

Question 12

What is/are the site(s) of infection for Alaria spp?

Answer 12

Adults in small intestine

Immature stages in the lungs