Editing Toxocariasis (section)

===Life cycle===
[[File:Toxocara canis LifeCycle.gif|thumb]]
Cats, dogs and foxes can become infected with ''Toxocara'' through the ingestion of eggs or by transmission of the larvae from a mother to her offspring.<ref name="CDC1"/><ref name="CDC4"/> Transmission to cats and dogs can also occur by ingestion of infected accidental hosts, such as earthworms, cockroaches, rodents, rabbits, chickens, or sheep.<ref name="Markell_2006"/><ref name="Holland_2006"/><ref name="Soskolne"/>

Eggs hatch as second stage larvae in the intestines of the cat, dog or fox host (for consistency, this article will assume that second stage larvae emerge from ''Toxocara'' eggs, although there is debate as to whether larvae are truly in their second or third stage of development).<ref name="Despommier"/><ref name="Holland_2006"/> Larvae enter the bloodstream and migrate to the lungs, where they are coughed up and swallowed.  The larvae mature into adults within the small intestine of a cat, dog or fox, where mating and egg laying occurs.<ref name="Holland_2006"/><ref name="ocular larva migrans"/><ref name="CDC1"/><ref name="Harris Linton"/> Eggs are passed in the feces and only become infective after three weeks outside of a host.<ref>{{Cite book|last=Becerril Flores | first = Marco Antonio | name-list-style = vanc |title=Parasitología médica| year = 2019 |isbn=978-1-4562-6784-1|edition=Quinta edición|location=México|oclc=1117384861}}</ref>  During this incubation period, molting from first to second (and possibly third) stage larva takes place within the egg.<ref name="Holland_2006"/><ref name="Soskolne"/> In most adult dogs, cats and foxes, the full lifecycle does not occur, but instead second stage larvae encyst after a period of migration through the body.  Reactivation of the larvae is common only in pregnant or lactating cats, dogs and foxes. The full lifecycle usually only occurs in these females and their offspring.<ref name="CDC1"/><ref name="CDC4"/>

Second stage larvae will also hatch in the small intestine of an accidental host, such as a human, after ingestion of infective eggs.<ref>{{cite journal | vauthors = Ahn SJ, Ryoo NK, Woo SJ | title = Ocular toxocariasis: clinical features, diagnosis, treatment, and prevention | journal = Asia Pacific Allergy | volume = 4 | issue = 3 | pages = 134–41 | date = July 2014 | pmid = 25097848 | pmc = 4116038 | doi = 10.5415/apallergy.2014.4.3.134 }}</ref> The larvae will then migrate through the organs and tissues of the accidental host, most commonly the lungs, liver, eyes, and brain.<ref>{{cite journal | vauthors = Lee RM, Moore LB, Bottazzi ME, Hotez PJ | title = Toxocariasis in North America: a systematic review | journal = PLOS Neglected Tropical Diseases | volume = 8 | issue = 8 | pages = e3116 | date = August 2014 | pmid = 25166906 | pmc = 4148222 | doi = 10.1371/journal.pntd.0003116 }}</ref>  Since L2 larvae cannot mature in accidental hosts, after this period of migration, ''Toxocara'' larvae will encyst as second stage larvae.<ref name="Markell_2006"/><ref name="Huh, Sun, Sooung"/><ref name="CDC1"/>