Editing Parasitism (section)

==== Trophically transmitted ====

[[File:Clonorchis sinensis 2.png|thumb|''[[Clonorchis sinensis]]'', the Chinese liver fluke, is trophically transmitted]]

[[wikt:trophic|Trophically]]-transmitted parasites are transmitted by being eaten by a host. They include trematodes (all except [[schistosomes]]), [[cestodes]], [[acanthocephala]]ns, [[Pentastomida|pentastomids]], many [[roundworms]], and many protozoa such as ''[[Toxoplasma]]''.<ref name=PoulinRandhawa2015/> They have complex life cycles involving hosts of two or more species. In their juvenile stages they infect and often [[encyst]] in the intermediate host. When the intermediate-host animal is eaten by a predator, the definitive host, the parasite survives the digestion process and matures into an adult; some live as [[intestinal parasite]]s. Many trophically transmitted parasites [[Parasite increased trophic transmission|modify the behaviour]] of their intermediate hosts, increasing their chances of being eaten by a predator. As with directly transmitted parasites, the distribution of trophically transmitted parasites among host individuals is aggregated.<ref name=PoulinRandhawa2015/> [[Coinfection]] by multiple parasites is common.<ref>{{cite journal |last1=Cox |first1=F. E. |url=https://researchonline.lshtm.ac.uk/17745/1/Concom.pdf |archive-url=https://web.archive.org/web/20171202083654/http://researchonline.lshtm.ac.uk/17745/1/Concom.pdf |archive-date=2 December 2017 |url-status=live |title=Concomitant infections, parasites and immune responses |series=122 |journal=Parasitology |volume=Supplement |pages=S23–38 |year=2001 |pmid=11442193 |doi =10.1017/s003118200001698x |s2cid=150432 }}</ref> [[Strongyloides stercoralis#Autoinfection|Autoinfection]], where (by exception) the whole of the parasite's [[biological life cycle|life cycle]] takes place in a single primary host, can sometimes occur in helminths such as ''[[Strongyloides stercoralis]]''.<ref name=ASP>{{cite web |title=Helminth Parasites |url=http://parasite.org.au/para-site/contents/helminth-intoduction.html |publisher=Australian Society of Parasitology |access-date=9 October 2017}}</ref>