Subclass Spiruria comprises mostly

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...

secernentea Secernentea was a class of nematodes in the Classical Phylogeny System (Chitwood, 1958) and is no longer in use. This morphological-based classification system has been replaced by the Modern Phylogeny system, where taxonomy assignment is based o ...

nematode The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...

s. In an alternate classification, they are treated as

suborder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...

Spirurina, with the orders listed here being ranked as

infraorder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...

s. The

Ascaridida The order Ascaridida includes several families of parasitic roundworms with three "lips" on the anterior end. They were formerly placed in the subclass Rhabditia by some, but morphological and DNA sequence data rather unequivocally assign them t ...

and the

Oxyurida Oxyurida is an order of nematode worms of the class Secernentea. It consists of four families, one of which contains the human pinworm (''Enterobius vermicularis''). Species Notable species include: * ''Enterobius vermicularis'', the human ...

, which include worms that infect many

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s (including

marine mammal Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears. They are an informal group, unified only by their reli ...

s), are sometimes placed in subclass

Rhabditia Subclass Rhabditia is mostly composed of parasitic nematodes (particularly in the Strongylida), though there are some free-living species as well (particularly in the Rhabditida). Phasmids (posterior sensory structures) are well-developed, whil ...

. But that seems as spurious as the erstwhile placement of the Rhigonematida in subclass Tylenchia. The

Camallanida The Camallanida are an order of nematodes. * Parasites of terrestrial and aquatic vertebrates * Copepods as obligatory secondary hosts They are sometimes included in the Spirurida as a suborder Camallanina. Notable species and genera * ...

and Drilonematida are sometimes included in the

Spirurida Spirurida is an order of spirurian nematodes. Like all nematodes, they have neither a circulatory nor a respiratory system. Some Spirurida, like the genus ''Gongylonema'', can cause disease in humans. One such disease is a skin infection with ...

and

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

, respectively.ToL (2002)

Some important species

*Giant roundworm (''

Ascaris lumbricoides ''Ascaris lumbricoides'' is a large parasitic worm that causes ascariasis in humans. A Nematoda, roundworm of genus ''Ascaris'', it is the most common parasitic worm in humans. An estimated one-sixth of the human population is at some point infe ...

''), causes

ascariasis Ascariasis is a disease caused by the parasitic roundworm ''Ascaris lumbricoides''. Infections have no symptoms in more than 85% of cases, especially if the number of worms is small. Symptoms increase with the number of worms present and may in ...

in humans *''

Toxocara canis ''Toxocara canis'' (also known as dog roundworm) is a worldwide-distributed helminth parasite of dogs and other canids. The name is derived from the Greek word "," meaning bow or quiver, and the Latin word "caro," meaning flesh.Bassert , J., & T ...

'', parasite of dogs *''

Anisakis ''Anisakis'' (a·nuh·saa·keez) is a genus of parasitic nematodes that have life cycles involving fish and marine mammals. They are infective to humans and cause anisakiasis. People who produce immunoglobulin E in response to this parasite ...

'', responsible for the human disease

Anisakiasis ''Anisakis'' (a·nuh·saa·keez) is a genus of parasitic nematodes that have life cycles involving fish and marine mammals. They are infective to humans and cause anisakiasis. People who produce immunoglobulin E in response to this parasite may ...

Footnotes

References

* (2002)
Nematoda
Version of 2002-JAN-01. Retrieved 2008-NOV-02. Parasitic nematodes of mammals Protostome subclasses {{parasitic animal-stub