Strongylida

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. This suborder includes (superfamily - included families): These are parasites of the digestive tracts of terrestrial snakes and, rarely, lizards. About 33 species are known in one family (Diaphanocephalidae), two genera (Diaphanocephalus and Kalicephalus) and six subgenera. Snakes can be orally infected with third-stage larvae experimentally, but it is a mystery how snakes become infected in the wild. Since snakes flick their tongue around to examine their environment, it is possible that the nematodes attach to the tongue. Kalicephalus species lack host specificity, and are intolerant of each other - different species space themselves apart in the host's gut. The hookworms, these have very large buccal cavities. They infect the small intestine of mammals. Many hookworms can infect the host by skin penetration, an important discovery made by A. Looss when he accidentally spilt larvae in water on his hand in 1898. The larvae release enzymes to assist their passage through the skin.