Introduction to endoparasites

Question 1

What are commensal parasites?

Answer 1

Less damaging parasites to completely benign relationship between two species

Question 2

What are symbiotic parasites?

Answer 2

They both rely on each other for survival, Lichens for example

Question 3

What are micropredator parasites?

Answer 3

Species that prey on tissues rather than whole organisms

Question 4

What are the two major classes of endoparasites?

Answer 4

• Protozoa
• Helminths (worms)

Question 5

What are some types of Protozoan parasites?

Answer 5

• Euglenozoa
• Metamonda
• Parabasalia
• Apicomplexa
• Amoebozoa

Question 6

What are the two classes of helminths?

Answer 6

• Phylum Platyhelminthes (trematoda/ fluke, Cestoda/ tapeworms)
• Phylum Nematoda

Question 7

What are some general features of helminths?

Answer 7

• Complex multicellular organisms
• Generally do not multiply in mammalian hosts
• Disease severity depends on worm load
• Usually causes chronic infections and disease

Question 8

What is a highly aggrevated distribution in infected populations called?

Answer 8

• wormy people/ wormy animals

Question 9

What does digenic mean?

Answer 9

There are more than 2 generations of different hosts to complete the life cycle

Question 10

What is the adult morphology of fluke?

Answer 10

• Two suckers
• Blind-ended gut
• All hermaphrodite apart from the schsitones

Question 11

What are some features of Cestodes (tapeworms)

Answer 11

• Segmented adults
• No gut
• Always parasitic
• Hermaphrodite

Question 12

What is the pathogenesis of cestodes?

Answer 12

• The adult worms are rarely pathogenic but adults in intestines cause ‘fullness’ and mild/ vague abdominal pain
• Juveniles are usually pathogenic
• cause cysts in muscles, organs, tissues, eyes, brain asymptomatic to severe (can cause death)

Question 13

What is the lifecycle called if there is only one host?

Answer 13

Direct

Question 14

What is the lifecycle called if there is two or more hosts?

Answer 14

Indirect

Question 15

What is the host called in which the parasite reaches maturity?

Answer 15

Definitive host

Question 16

What is the host called that harbours the parasite in developing stages

Answer 16

Intermediate host

Question 17

What are two examples of indirect lifecycles?

Answer 17

• Transmission via a vector
• Transmission by ingesting another vector

Question 18

What is the definition of pathogenesis?

Answer 18

• The biological mechanisms that lead to a diseased state

Question 19

What is the definition of parasite pathogenesis

Answer 19

How a parasitic infection causes disease

Question 20

What are some features of parasitic diseases

Answer 20

• Usually long-term and chronic rather than acute
• Mortality generally only occurs after a long period of sickness
• Disease severity often depends on parasite burden
• Pathology may simply be a side effect of infection…
  OR
• An adaptive strategy to enhance parasite transmission

Question 21

Likelihood of disease and clinical presentation depend on

Answer 21

• Parasite density
• Parasite species or strain
• Host factors

Question 22

What are some other host factors?

Answer 22

• Immunosuppression
• Co-infections
• Nutritional status

Question 23

What is a difference between male and female nematodes?

Answer 23

Male nematodes have curled tails