Nematodes

Roundworms or threadworms; spindle-shaped, unsegmented, a few mm to about 1 m long, separately sexual parasites. Development proceeds from the egg through 4 larval stages to the adult worm. Some species require an intermediate host for their development.

The worm class of nematodes contains about 30,000 species of which many have human pathological significance (see classification). The classification of nematodes into:

• Nematodes with intestinal manifestation
• and
• nematodes with extraintestinal manifestation

is fluid. However, for diagnostic purposes, it is significant to assign - intestinal infestation/tissue infestation of crucial importance (stool examination, blood examination, histology).

Classification according to clinical criteria:

Intestinal nematodes:

• Enterobius vermicularis (pinworm: causative agent of oxyuriasis)
• Ascaris lumbricoides (roundworm: causative agent of ascaridiasis)
• Trichuris trichiuria (whipworm: causative agent of trichuriosis)
• Ancylostoma duodenale (hookworm: causative agent of ancylostomiasis)
• Trichinella spiralis (trichinae).

Filariae (causative agent of lymphatic filiarosis):

• Wucheria bancrofti a. Brugia species (causative agent of lymphatic filiarosis)
• Loa Loa (causative agent of loiasis)
• Onchocerca volvulus (causative agent of onchocerciasis = river blindness)
• Dracunculus medinensis (medina worm: causative agent of dracunculosis).

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Ankylomstomatidae (hookworms)

• Ancylostoma duodenale (the term "duodenal" is misleading, worms live in the jejunum and ileum pathogen of ancylostomiasis)
• Necator americanus (hookworm; causative agent of ancylostomiasis)
• Ancylostoma braziliense (hookworm: causative agent of larva migrans cutanea syndrome)

Ascarididae (flushing worms)

• Ascaris lumbricoides (roundworm: large roundworms up to 40cm long, causative agent of ascaridiasis; affects about 1 billion people)
• Anisakis simplex (causative agent of anisakiasis = herring worm disease)
• Toxocara canis (roundworms of dogs; larva migrans visceralis syndrome)
• Toxcara cati (roundworms of cats; larva migrans visceralis syndrome)

Filariidae (nematodes, causative agent of lymphatic filiarosis)

• Wuchereria bancrofti and Brugia species (causative agent of lymphatic filiarosis)
• Loa Loa (pathogen of loiasis)
• Onchocerca volvulus (causative agent of onchocerciasis = river blindness)

Spiruridae (nematodes whose development requires an intermediate host, often small crustaceans of the genus Cyclops)

• Dracunculus medinensis (medina worm or dragon worm; erector of dracunculosis).

Oxyuridae (pinworms)

• Enterobius vermicularis (pinworm: causative agent of oxyuriasis; about 1 billion people are affected)

Rhabdititae (dwarf pinworms; about 80 million people are infected)

• Strongyloides stercoralis (dwarf threadworms: strongyloidosis, causative agent of larva migrans cutanea syndrome)
• Strongyloides fuelleborni (Dwarf threadworms: causative agent of Larva migrans cutanea syndrome)

Trichinella (causative agent of trichinosis)

• Trichinella spiralis (trichinae).

Trichuridae

• Trichuris trichiura (whipworm: causative agent of trichinosis)