Spiruria
Encyclopedia
Subclass Spiruria comprises mostly parasitic secernentea
n nematodes. In an alternate classification, they are treated as suborder Spirurina, with the orders listed here being ranked as infraorders.
The Ascaridida
and the Oxyurida
, which include worms that infect many mammal
s (including marine mammal
s), are sometimes placed in subclass Rhabditia
. But that seems as spurious as the erstwhile placement of the Rhigonematida in subclass Tylenchia. The Camallanida
and Drilonematida are sometimes included in the Spirurida
as suborder and superfamily
, respectively.
Secernentea
Secernentea are the main class of nematodes, characterised by numerous caudal papillae and an excretory system possessing lateral canals. Like all nematodes, they have no circulatory or respiratory system....
n nematodes. In an alternate classification, they are treated as suborder Spirurina, with the orders listed here being ranked as infraorders.
The Ascaridida
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 assigns them to the Spiruria...
and the Oxyurida
Oxyurida
Oxyurida is an order of nematode worms of the class Secernentea. It consists of four families, one of which contains the human pinworm ....
, which include worms that infect many mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s (including marine mammal
Marine mammal
Marine mammals, which include seals, whales, dolphins, and walruses, form a diverse group of 128 species that rely on the ocean for their existence. They do not represent a distinct biological grouping, but rather are unified by their reliance on the marine environment for feeding. The level of...
s), are sometimes placed in subclass Rhabditia
Rhabditia
Subclass Rhabditia is mostly composed of parasitic nematodes , though there are some free-living species as well...
. But that seems as spurious as the erstwhile placement of the Rhigonematida in subclass Tylenchia. The Camallanida
Camallanida
The Camallanida are an order of nematodes.* Parasites of terrestrial and aquatic vertebrates* Copepods as obligatory secondary hostsThey are sometimes included in the Spirurida as a suborderCamallanina....
and Drilonematida are sometimes included in the Spirurida
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...
as suborder and superfamily
Taxonomic rank
In biological classification, rank is the level in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, and class. Each rank subsumes under it a number of less general categories...
, respectively.
Some important species
- Giant roundworm (Ascaris lumbricoidesAscaris lumbricoidesAscaris lumbricoides is the giant roundworm of humans, belonging to the phylum Nematoda. An ascarid nematode, it is responsible for the disease ascariasis in humans, and it is the largest and most common parasitic worm in humans. One-sixth of the human population is estimated to be infected by this...
), causes ascariasisAscariasisAscariasis is a human disease caused by the parasitic roundworm Ascaris lumbricoides. Perhaps as many as one quarter of the world's people are infected, with rates of 45% in Latin America and 95% in parts of Africa. Ascariasis is particularly prevalent in tropical regions and in areas of poor...
in humans - Toxocara canisToxocara canisToxocara canis is worldwide distributed helminth parasite of dogs and other canids. T. canis are gonochorists, adult worms measure from 9 to 18 cm, are yellow-white in color, and occur in the intestine of the definitive host. In adult dogs, the infection is usually asymptomatic. By the...
, parasite of dogs - AnisakisAnisakisAnisakis is a genus of parasitic nematodes, which have a life cycle involving fish and marine mammals. They are infective to humans and cause anisakiasis...
, responsible for the human disease Anisakiasis