Parasitology - Lecture 9

Question 1

what species and where does Opistorchis felineus/ tenuicollis infect?

Answer 1

dogs, cats, humans.

bile ducts

Question 2

Whats species and where does Opistorchis viverrini infect?

Answer 2

dogs, cats, humans

bile ducts

Question 3

What species and where does Clonorchis sinensis infect?

Answer 3

humans, dogs, cats, igs

bile ducts

Question 4

Describe the lifecycle for Clonorchis/ Opistorchis spp.

Answer 4

• eggs pooped out
• snails ingest eggs and miracidia hatch. then go to sporocyst, then rediae, then cercaria
• cercaria leave snail, swim in water looking to infect fish
• cercaria bore through fish skin and encyst as metacercaria
• DH ingests infected fish
• juveniles reach liver via the bile ducts
  PPT= 3-4 weeks
  can live for 40 years

Question 5

describe the general morphology of cestodes

Answer 5

• up to 25m
• segmented body
• no GIT
• most locate in small intestine
• hermaphrodites
• lifecycle requires IH
• body divided into scolex, neck and strobila (made up of proglottids)
• on strobila, there are immature, mature and gravid proglottids. gravids detach and reach environment intact or partially disintegrated
• parenchyma fills space between internal organs
• longitudinal, transverse and circular muscle systems

Question 6

What is the name of the process that produces proglottids? where does it take place?

Answer 6

budding (strobilistion) in the neck

Question 7

What is the tegument of a cestode and what is its purpose?

Answer 7

covers the body and serves as a protective coating

can absorb nutrients through this layer

Question 8

describe the structure of a proglottid

Answer 8

contains one set of female and one set of male reproductive organs