Nematodes 1

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

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causes Hyperinfection