page_title: Strongylida
section_title: Trichostrongyloidea
hierarchical_section_title: Strongylida / Major superfamilies / Trichostrongyloidea
caption_attribution_description: English: Gastrointestinal parasites in seven primates of the Taï National Park - Helminths Figure 3l of paper. Egg of Trichostrongylus sp.
context_page_description: The Strongylida suborder includes many of the important nematodes found in the gastrointestinal tracts of ruminants, horses, and swine, as well as the lungworms of ruminants and the hookworms of dogs and cats.
context_section_description: Trichostrongyloidea are divided into 14 families and 24 subfamilies. These worms have very small mouths and are found in a large number of hosts. They generally infect the stomach or intestine. Species that infect herbivorous hosts climb onto vegetation via films of moisture. Some species such as those infecting rodents can use either the oral or percutaneous route. There are unusual features in the development and transmission of some Trichostrongyloidea species. For example, Ollulanus tricuspis, which infects the stomach of pigs, is autoinfective: the sole means of transmission is through the pig vomiting. Arrested development is a well-studied feature, which may occur in temperate zones when the weather is too cold, or when it is too dry. This is known as seasonal arrest. In ewes, they wait for parturition and lactation, when there will be a population of young animals with little or no immunity; the sudden production of eggs by newly matured worms is known as spring rise. Another factor involved in stimulating arrest is overpopulation of adult worms.
caption: Egg of Trichostrongylus sp.
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