Nematodes 1

What is the common Name of Nematodes

What is the common Name of Nematodes

Round Warms

General Characteristics of Nematodes

• Unsegmented

• Bilaterally Symmetrical

• Elongated Cylindrical/Filariform

• Tapered at both ends

• Colorless

• Cross section is rounded

• Have body Cavity

• Vary in Length

• Separate Sex

Shortest Nematodes

Strongyloides Stercolaris

Largest Nematodes

Dracanculus Medinensis

Male or Female Nematode is Shorter

Male

Characteristics of Male Nematodes

• Ventrally curved Posterior End

• Anterior Part has Lips/Teeth/Hooks

Nematodes are classified according to

• Habitat

• Mode of Infection

• whether they are laying Eggs or Larvae

Nematodes habitat based classification

• intestinal

  • Small Intestine

    • Ascaris

    • Hook Worms => Ancylostoma , Necator

    • Strongyloids

    • Cappillaria

    • Trichinella

  • Large Intestine

    • Trichocephalus

    • Entrobius

• Tissue

  • Lymphatic

    • W.Bancrofti

    • W.Malaye

  • S.C

    • Loa Loa

    • Drancanculus Medinensis

    • Onchocerca Volvulus

Small Intestinal Nematodes

• Ascaris

• Hook Worms => Ancylostoma , Necator

• Strongyloids

• Cappillaria

• Trichinella

Large Intestinal Nematodes

• Trichocephalus

• Entrobius

Lymphatics Tissue Nematodes

• W.Bancrofti

• W.Malaye

S.C Tissue Nematodes

• Loa Loa

• Drancanculus Medinensis

• Onchocerca Volvulus

Nematoda mode of infection based classification

• Eggs → Entrobius + Ascaris

• Cyclops → Medinensis

• Fish containing larvae → Cappillaria

• skin penetration by 3rd filarifiorm larvae→ Hook Worms + Strogyloides

• Blood Sucking Orthopods → Filarial Worms

Nematodes which are infective by Eggs

Entrobius + Ascaris

Nematodes which are infective by Cyclops

Medinensis

Nematodes which are infective by Fish containing larvae

Cappillaria

Nematodes which are infective by skin penetration by 3rd filarifiorm larvae

Hook Worms + Strogyloides

Nematodes which are infective by blood sucking Orthopods

• Filarial Worms

Classification Based on laying eggs or larvae

• Oviparous => eggs

• Viviparous => Microfilaria

• Ovoviviparous => eggs hatch inside females

Oviparous Nematodes

• Hookworms

• Trichocephalus

• Ascaris

• Cappillaria

• Entrobius

Viviparous Nematodes

• Filarial Worms

Ovoviviparous Nematodes

Strogyloides Stercolaris

Monoxenous Nematodes / examples

• needs one host

• Most nematodes

Heteroxenous Nematodes / examples

• need intermediate host

• Filarial Worms

Nematode with Free-living life cycle in Soil

Strongyloides

Nematode passing mature/embryonated egg

• Entrobius

Nematode passing immature egg

• Hook worms

• Ascaris

Nematode with larval development in Soil (free-living conditions)

• Strongyloides

Stages of life cycle in Nematodes

• four larval Stages

• Adult

Migratory Nematodes

• Ascaris

• Ancylostoma

• Strongyloides

Nematode has one host act as intermediate and definitive

Trichinella

What is Autoinfection

Types

• reinfection of the same host by himself

  • External

  • Internal

External Autoinfection

Examples

Feco oral/ hand to mouth

H.nana - Entrobius

Internal Autoinfection Examples

Strongyloides

Cappillaria

----------------------------------

causes Hyperinfection