Nematodes

Question 1

What are the different forms of nematode?

Answer 1

Rhabditiform and Filariform (the rhabditiform are shorter than filariform)

Question 2

What are the different nematode classes?

Answer 2

Secernentea and Chromadorea and Enoplea

Secernentea= Rhabditia and Spiruria

Rhabditia –> Rhabditoidea and Strongyloides

Enoplea= Dorylaimia and Enoplia

Dorylaimia –> Trichinellia

Question 3

The parasitic diseases caused by helminth (nematodes and platyhelminths)

Answer 3

Question 4

What are the subgroups of Trichinellida?

Answer 4

Trichinella spiralis

Capillaria

Trichuris

Question 5

What are the filariasis diseases transmitted by?

Answer 5

Mosquitos

Question 6

What are the type of filariasis?

Answer 6

Lymphatic –> Due to Wuchereria bancrofti, Brugia malayi

Subcutaneous –> Due to Loa Loa, Onchocerca volvulus

Serous cavity –> Due to mansonella ozzardi and mansonella perstans

Question 7

Why is Ivermectin toxic to mammals?

Answer 7

Due to similarity of invertebrates- specific channels to vertebrates GABAA-gated chloride channels that inhibit interneurons of CNS

Question 8

What is the prevention and control for strongyloides?

Answer 8

• Wear shoes when walking on soil
• Proper sewage disposal and faecal management

Question 9

What is the pathogenesis for strongyloides?

Answer 9

Penetrate skin –> small intestine where they lay their eggs

Can be severe or life threatening in person on corticosteroids or immunosuppressants as can lead to hyperinfection or dissemination

Question 10

What is the prevention and control from Rhabditodea?

Answer 10

Same as strongyloidea

Question 11

What is the prevention and control for Trichinellida?

Answer 11

• wash hands when handling raw meat
• Wash surfaces and meat grinders
• Freeze pork well

Question 12

What is the pathogenesis for Trichinellida?

Answer 12

This infection is due to eating raw or undercooked meat

A zoonotic infection

Infectious cysts in striated muscle tissue –> L1 larvae released –> Mature to adults in small intesting –> New larvae then released by adults

Question 13

What is the prevention and control for Guinea worm?

Answer 13

• Safe drinking water
• Vector control i.e, Kill copepods
• Health education
• GWEP= a group trying to eradicate guinea worm

Question 14

What is the pathogenesis for guinea worm?

Answer 14

Ingestion –> penetrate stomach and intestinal wall –> connective tissue fo abdomen to mate –> escape out of formed blister

NO treatment

Question 15

What is the prevention and control for Onchocercus volvulus?

Answer 15

DEET

Cover skin to prevent biting from black fly

Question 16

What can cause river blindness with onchocercus volvulus and what is the treatment?

Answer 16

Effect cornea which effects vision

Treat with Ivermectin

Question 17

Pros and Cons to C.elegans as a model organism?

Answer 17

Pros

• Cheap and easy to keep in laboratories
• Only have a 2-week life span
• Transparent
• Undergo a particular aging process whcih allows them to be easily physiologically or genetically observed

Cons

• Simple body plan
• Lack many defined organs and tissues; which is evolutionary distinct to humans
• Only 1mm in length which makes studying their biochemistry difficult

Question 18

Both trematodes and cestodes have a scolex, what does the nematode have instead of this?

Answer 18

Muscular oesophagus

Question 19

Nematodes have a Pseudocoelum what is this?

Answer 19

A false body cavity that lies between body wall and gut

It contains coelomocyte which provides turgor-hydrostatic pressure for animals as a whole, lubricant between tissues and a medium for instracellular signalling and nutrient transport