Chapter 8 - Nematodes

Question 1

What are the four nodes of Transmission?

Answer 1

1-Faecal-oral transmission of eggs or larvae 2-Transdemal transmission of infective larvae in the soil 3-Vector-Borne transmission 4-Predator-prey Transmission

Question 2

Description of Faecal-oral transmission of eggs or larvae

Answer 2

-Passed in the faces of one host and ingested with the foodwater by another (ex.gingestion of Trichuris eggs leads directly to gut infections in humans while the ingestion of Ascaris eggs and Strongyloides larvae leads to a pulmonary migration phase before gut infection in humans)

Question 3

Description of Transdermal transmission of infective larvae in the soil

Answer 3

-(geo-helminths) actively penetrating the skin and migrating through the tissues to the gut where adults develop and produce eggs that are voided in host facies. —> Example: Larval hookworms penetrating the skin, undergoing pulmonary migration and infecting the gut where they feed on blood. Resulting in iron-deficient anaemia in humans.

Question 4

Description of Vector Borne Transmission

Answer 4

-Of the larval stages taken up by blood sucking arthropods or undergoing amplification in aquatic molluscs. —>Example: Onchocera microfilariae ingested by blackflies and injected into new human hosts. Schistoma eggs release miracidia to infect snails where they multiply and form cercariae which are release to infect new hosts)

Question 5

Description of Predator-prey transmission

Answer 5

-Of encysted larvae within prey animals (vertebrate or invertebrate) being eaten by predators where adult worms develop and produce eggs —>Example: Dracunculus larve in coepods ingested by humans leading to guinea worm infection. Taenia cysticerol in beef and pork eaten by humans, or Echinococcus hydalid cysts in offal being eaten by dogs.

Question 6

Short description of the Nematodes

Answer 6

-Also known as Round Worms -Have long thin unsegmentated tube-like bodies with anterior mouths and longitudinal digestive tracts. They have a fluid-filled internal body cavity (pseudoceium) which acts as a hydrostatic skeleton providing rigidity (so called tubes under pressure) -Worms use longitudinal muscles to produce a sideways thrashing motion. -Adult worms form separate sexes with well developed reproductive systems.

Question 7

Nematodes are part of what and include who?

Answer 7

-Part of the Helminths -Include: —->Nematodes: Round Worms —->Trematodes: Flatworms —->Cestodes: Tapeworms

Question 8

What are the Instestinal Species?

Answer 8

-Enterobius vermicutaris = Pinworm -Trichuris trichiura = Whipworm -Ascaris lumbricoides = Large intestinal Roundworm -Necator americanus = New World Hookworm -Ancylostoma duodernale = Old World Hookworm -Strongyloides stercoralis = Threadworm

Question 9

Which are the Intestinal-Tissue Species?

Answer 9

-Trichinella spiralis = Trichina worm -Dracunculus medinensis = Guinea Worm

Question 10

Define the Terms -Autoreinfection -Buccal capsule -Buccal cavity -Chitin

Answer 10

-Reinfecting oneself -Long oral cavity; also known as a buccal cavity -Long oral cavity; also known as a buccal capsule -Shell made up of a thick nitrogen-containing polysaccharide coating

Question 11

Define the Terms -Copepod -Copulation -Corticated

Answer 11

-Freshwater fleas -Mating of select worms -Eggs containing a mammilated albumious material

Question 12

Define Cuticle

Answer 12

-Surface covering present on adult nematodes

Question 13

Define Decorticated

Answer 13

-Eggs lacking an outer mammilated albuminous coating

Question 14

Define Egg

Answer 14

-Female sex cells after fertilization

Question 15

Define Embryonated

Answer 15

-Fertilized egg

Question 16

Define Filariform larva

Answer 16

-Infective, nonfeeding stage that occurs after the rhabditiform larve completes their second molt

Question 17

Define Gravid

Answer 17

-Pregnant

Question 18

Define Larva

Answer 18

-Junvenile Worms

Question 19

Define Nematode

Answer 19

-Multicellular parasites that appear round in cross section

Question 20

Define Retroinfection

Answer 20

-Infective pinworm eggs that migrate back into the host body, develop and reproduce rather than becoming dislodged

Question 21

Members of the class Nematoda assume three basic morphologic forms. What are they and additional info

Answer 21

-Eggs —>Vary in size and shape -Larvae —->Located inside the fertilized eggs; emerge and continue to mature -Adult worms —->Develop from the maturing larvae —->Sexes separate (females larger than males) —->Equipped with a digestive and reproductive system

Question 22

Three possible factors that may contribute to severity of infection:

Answer 22

-Number of worms present -Length of time the infection persists -Overall Health of the host *Side note: reinfection and autoreintection also play a role in determining severity

Question 23

life cycle of Enterobius vermicularis

Answer 23

Question 24

identify

Answer 24

Enterobius vermicularis
Eggs

Question 25

Identify this

Answer 25

Enterobius vermicularis Egg

Question 26

Identify

Answer 26

Enterobius vermicularis adult worms

Question 27

Trichuris trichiura Life Cycle

Answer 27

Question 28

identify this

Answer 28

Trichiura worms

Question 29

Identify this

Answer 29

Trichuris trichiura egg

Question 30

Ascaris lumbricoides Life Cycle

Answer 30

Question 31

identify

Answer 31

Ascaris lumbricoides Adult Female

Question 32

Identify

Answer 32

Ascaris lumbricoides adult male

Question 33

Identify this

Answer 33

Ascaris lumbricoides

Question 34

Baylisascaris procyonis life cycle

Answer 34

Question 35

Human Hookworm Egg Life Cycle

Answer 35

Question 36

Zoonotic Hookworm egg life cycle

Answer 36

Question 37

Identify this

Answer 37

Hookworm Egg

Question 38

Identify

Answer 38

Hookworm Rhabditiform Larvae

Question 39

Life cycle of Strongyloides stercoralis

Answer 39

Question 40

Trinchinella spiralis Life Cycle

Answer 40

Question 41

Identify

Answer 41

Trichinella Spiralis encysted larvae

Question 42

Dracunculus medinensis Life Cycle

Answer 42

Question 43

The life Cycle of Gunea Worm Disease

Answer 43