Cyclophyllideans (True Tapeworms)

Question 1

What are the definitive hosts of Echinococcus granulosus?

Answer 1

Wild canids (wolves)- wild cycle
Domestic (dogs)- pastoral cycle
Found in the small intestine

Question 2

What are the intermediate hosts of Echinococcus granulosus?

Answer 2

Moose, caribou, reindeer (wild)
Sheep, cows, goat (domestic)
Found in liver, lungs, occasionally the brain

Question 3

What is the type of larval infection of Echinococcus granulosus?

Answer 3

Unilocular hydatid cyst

Question 4

Echinococcus granulosus and multiocularis life cycles and Prepatent periods

Answer 4

Indirect with 2 cycles (wild and domestic)
Prepatent: 6-8 weeks

Question 5

Echinococcus granulosus and multiocularis characteristics

Answer 5

Small
Larger gravid proglottid at posterior end
Proglottids rupture prior to defecation and are not observed in feces
2-8 mm in length

Question 6

Domestic (pastoral) lifecycle of Echinococcus granulosus

Answer 6

1. Proglottids in dog rupture in small intestine, eggs passed in feces
2. Intermediate host ingests eggs with hexacanth larva that will develop into unilocular hydatid cysts
3. Dog eats unilocular hydatid cyst within the intermediate host
4. Unilocular hydatid cyst develop into adult tapeworms

Question 7

Wild (sylvatic) lifecycle for Echinococcus granulosus

Answer 7

1. Proglottids in wild canid rupture in small intestine, eggs passed in feces
2. Intermediate host ingests eggs with hexacanth larva that will develop into unilocular hydatid cysts
3. Wolf eats unilocular hydatid cyst within the intermediate host
4. Unilocular hydatid cyst develop into adult tapeworms

Question 8

Public health significance of Echinococcus granulosus

Answer 8

Zoonotic
Causes unilocular hydatid disease in humans

Question 9

Clinical signs of Echinococcus granulosus and multiocularis

Answer 9

rarely causes disease in definitive host
Heavy infection
Inflammation of testes
Diarrhea
Weight loss
signs in intermediate, leads to carcass condemnation and economic loss

Question 10

Diagnosis of E. granulosus and multiocularis

Answer 10

Fecal flotation or direct smear

Question 11

Characteristics of eggs of E. Granulosus and Multiocularis

Answer 11

Thick capsule containing a hexacanth larva

Question 12

Treatment and Prevention of E. Granulosus and multiocularis

Answer 12

Praziquantel
Keep dog from eating sheep offal (viscera)

Question 13

Hosts of E. Multilocularis

Answer 13

Definitive: foxes (sylvatic)
Dogs and cats (domestic)- in small intestines
Intermediate: rodents, man, domestic herbivores- in liver, lungs, other organs (brain)

Question 14

Type of larval infective stage of E. Multilocularis

Answer 14

Multiocular hydatid cyst

Question 15

Domestic (pastoral) lifecycle of E. Multiocularis

Answer 15

1. Proglottids in dog or cat rupture in small intestine, eggs passed in feces
2. Intermediate host ingests eggs with hexacanth larva that will develop into multiocular hydatid cysts
3. Dog or cat eats multiocular hydatid cyst within the intermediate host
4. Multiocular hydatid cyst develop into adult tapeworms

Question 16

Wild (sylvatic)cycle of E. Multupiocularis

Answer 16

1. Proglottids in fox rupture in small intestine, eggs passed in feces
2. Intermediate host ingests eggs with hexacanth larva that will develop into multiocular hydatid cysts
3. Fox eats multiocular hydatid cyst within the intermediate host
4. Multiocular hydatid cyst develop into adult tapeworms

Question 17

Public health significance of E. Multiocularis

Answer 17

Zoonotic
Causes alveolar hydatid disease in humans which may be fatal