Introduction

Question 1

Transmitted by ingestion of eggs

Answer 1

Trichuris
Enterobias
Ascaris

Question 2

Larval forms

Answer 2

First stage and Second stage( rhabditiform) - are non infectious, feeding forms
The third stage( filariaform) - infectious non feeding form. As adults they live within the human body except Strongyloides

Question 3

Eosinophilia is seen in

Answer 3

Tissues after migration of nematodes: Strongyloides
Trichinella
Ascaris
Ancylostoma
Nectator

Question 4

Defense against helminths

Answer 4

Host defense against helminths are stimulated by release of interleukins synthesized by Thelper cells.
IgE prod increased by by IL-4
Eosinophils number is increased by IL-5
Eosinophils don’t digest the organism rather they attach to the surface of parasite via IgE and secrete cytotoxic enzymes

Question 5

Classifications of helminths

Answer 5

Location of the adult in the body
1. Intestinal nematodes
a) small intestine- Ascaris, ancylostoma, Necator, Strongyloides, Trichinella
b) Enterobius, Trichuris.
2. Tissue nematodes
a) lymphatic- Wuchureria, Brugia
b) subcutaneous - Loa loa, Onchocerca, Drancunculus
c) mesentry- Mansonella
d) conjunctiva- loa loa

B. Mode of infection
1. By ingestion a) Eggs- Truchuria, ascaris, Enterobius
b) Larvae within intermidiate host- Druncuculus, Trichinella.
2. Penetration of skin- ancylostoma, Necator Strongyloides
3. Blood sucking insects- Filariae
4. By inhalation of dust containing eggs- Ascaris, Enterobius

C. Based on whether they lay eggs or larvae
Oviparous- laying eggs a) unsegmented eggs- Ascaris, Trichuris
b) segmented eggs- ancylostoma, Necator
c) egg containing larvae - enterobius
2. Viviparous- producing larvae- trichinella, Wuchureria, Brugia, Drancunculus

3. Ovoviviparous - laying eggs containing fully formed larvae which hatch out immediately - Strongyloides