ANI SCI 320 Lecture 10 : Helminths

Question 1

What is Dracunculus Medinensis (Guinea worm)?

Answer 1

Parasite (nematode)

Question 2

What are some characteristics of Dracunculiasis?

Answer 2

1. Oldest disease known to human kind
2. Remains endemic in 3 countries
3. Infects humans and domestic animals
4. Transmitted by drinking water

Question 3

What is the the Greek god Asclepius associated with?

Answer 3

Healing and medicine

Question 4

What do historians believe about extraction of dracunculus medinensis?

Answer 4

Led to the symbolism behind the Rod of Asclepius

Question 5

The caduceus is recognized as…..

Answer 5

Symbol of commerce and negotiation

Question 6

What are helminths?

Answer 6

Parasitic worms

Question 7

What are 5 characteristics of Helminths?

Answer 7

1.Eukaryotic
2. Relatively Large
3. Well-developed organ systems
4. Flattened and covered with plasma membrane or cylindrical and covered with cuticle
5. Adult form - helminths are unable to multiple

Question 8

Where are helminth infections most common?

Answer 8

Poor countries, distribution is determined by climate, hygiene, diet, and exposure to vectors

Question 9

TRUE or FALSE? Helminth infections are most commonly asymptomatic?

Answer 9

TRUE

Question 10

Production losses of helminth infections are due to what 2 things?

Answer 10

1. Competition for nutrients
2. Damage to body systems

Question 11

TRUE or FALSE? Helminths are zoonotic?

Answer 11

TRUE

Question 12

What are 3 branches of parasitic helminths?

Answer 12

1. Flatworms
2. Roundworms
3. Thorny headed worms

Question 13

What is a brand of round worms?

Answer 13

Nematodes

Question 14

What are two branches of flat worms?

Answer 14

1. Trematodes (flukes)
2. Cestodes (tapeworms)

Question 15

Answer the following for Trematodes
a. Appearance
b. Cross-Section
c. Body Cavity
d. Gut
e. Life Cycle
f. Reproduction

Answer 15

a. Leaf like
b. Flattened
c. Absent
d, Blind sack
e. Indirect
f. Monoecious

Question 16

Answer the following for Cestode
a. Appearance
b. Cross-Section
c. Body Cavity
d. Gut
e. Life Cycle
f. Reproduction

Answer 16

a. Tape like
b. Flattened
c. Absent
d. Absent
e. Indirect
f. Monoecious

Question 17

Answer the following for Nematode
a. Appearance
b. Cross-Section
c. Body Cavity
d. Gut
e. Life Cycle
f. Reproduction

Answer 17

a. Worm-like
b. cylindrical
c. Fluid-filled
d. True gut
e. Direct and indirect
f. Dioecious

Question 18

What are the 3 different host types for helminth infections?

Answer 18

1. Definitive
2. Intermediate
3. Paratenic

Question 19

What is a definitive host?

Answer 19

Host where adult stages develop

Question 20

What is an intermediate host?

Answer 20

Host where immature stages develop to produce usually infective stages of it without reaching to maturity

Question 21

What is a paratenic host

Answer 21

Immature stage retained but no parasite developed

Question 22

What are the 4 transmission routes for helminth infections?

Answer 22

1. Fecal oral
2. Transdermal
3. Vector-borne
4. Predator-prey

Question 23

What is the fecal oral route?

Answer 23

Eggs or larvae passed in the feces of one host and ingested with food/water by another

Question 24

What is the transdermal route?

Answer 24

Infective larvae in the soil actively penetrate the skin and migrating through the tissues to the gut where adults develop and produce eggs that are released in the host feces.

Question 25

What is the vector borne transmission route?

Answer 25

Larval stages taken up by the blood sucking arthropods or undergoing amplification in aquatic molluscs

Question 26

What is the predator prey transmission route?

Answer 26

Encysted larvae within prey animals being eaten by predators where adult worms develop and produce eggs

Question 27

What are two morphological adaptations that work as survival strategies for helminth infections?

Answer 27

1.Degeneration of organs
2. Attainment of new organs

Question 28

What are physiological adaptations for helminths as a survival strategy?

Answer 28

Secretion of anti-enzymes and mucous
Facultative anaerobic respiration
Osmotic pressure adaptability
Chemotaxis
Hypobiosis
Reproductive adaptations

Question 29

What is avoidance of host defenses as a survival strategy for helminths?

Answer 29

Acquisition of host molecules to reduce antigenicity, releases substances that depress immune system and produces anti-compliment factors

Question 30

What are the 5 forms of direct damage from worm activity?

Answer 30

1. Blockage of internal organs
2. Pressure exerted by growing parasites
3. Physical damage
4. Chemical damage
5. Nutritional impacts in under nutritioned individuals or animals

Question 31

What are the 3 forms of indirect damage from the host response?

Answer 31

1. Hypersensitivity based inflammatory changes
2. Local allergic responses
3. Structural changes