This document provides information about nematodes, including their: 1) Classification within the kingdom Animalia and phylum Nemathelminthes. 2) General characteristics such as size, shape, presence of a buccal capsule and teeth. 3) Life cycle which involves 4 larval stages and 1 adult form, and usually requires a single host like humans. 4) Modes of infection such as ingestion, skin penetration, or transmission by blood-sucking insects.

1. NEMATODES
Presented by,
Rahul Unni K
Mentor,
Dr.Bhaskaran

2. Parasites
Protozoa
Sarcodina
(Amoebas)
Sporozoa
(Sporozoans)
Mastigophora
(Flagellates)
Ciliata
(Ciliates)
Metazoa
(Helminths)
Platyhelminthes
(Flatworms)
Nemathelminthes
(Round worms)
Adenophorea Secernentea
CLASSIFICATION OF PARASITES

3. Classification of NEMATODES
• SYSTEMIC CLASSIFICATION
KINGDOM :ANIMALIA
PHYLUM:NEMATHELMINTHES
CLASS : NEMATODA
SUB CLASS : ADENOPHOREA
SECERNENTEA

4. Nematodes
• General characteristics –
• Size – 1mm to 1 m
• Shape - Elongated, Cylindrical, Unsegmented
• Head end – Hooks and sucker absent, Well developed buccal capsule with
teeth or cutting plates seen in some species.
• Alimentary canal – Complete with anus.
• Body cavity – Present and known as psuedocoele. viscera remains
suspended in the pseudocoele.
• Sex – Separate (Dioecious)

5. Life Cycle
• Consists of 4 larval stages and 1 adult form
• Requires one host (except filarial worms, Dracunculus – need
two hosts).
• Optimum host – Man
• Nematodes localise in intestinal tract and eggs pass out with
the faeces of the host.

6. Modes of infection
• By Ingestion of eggs
• Eggs : Ascaris, Enterobius
• Larvae within intermediate host : Dracunculus.
• Encysted larvae in muscle : Trichinella
• By penetration of skin: Ancylostoma, Strongyloides
• By blood sucking insects : Filariae
• By inhalation of dust containing eggs : Ascaris, Enterobius

7. Classification
• On the basis of habitat of adult worms
• Intestinal Human Nematodes
» Small intestine : Ascaris lumbricoides, Ancylostoma duodenale,
Strongyloides stercoralis, Trichenella spiralis
» Large intestine : Trichuris trichiura, Enterobius vermicularis
• Somatic Human Nematodes
» Lymphatics : Wuchereria bancrofti, Brugia malayi, Brugia timori
» Skin/subcutaneous : Loa loa, Dracunculus medinensis
» Mesentry : Mansonella ozzardi, Mansonella perstans
» Conjuctiva : Loa loa
• Zoological Classification