Strongyloides LifeCycle en (01)

Autor:

CDC/Alexander J. da Silva, PhD/Melanie Moser, Courtesy: Public Health Image Library

Credit:

http://www.publicdomainfiles.com/show_file.php?id=13520139013874

Krótki link:

https://plwiki.pl/b/1093c6

źródło:

Wikimedia Commons

Wymiary:

3150 x 2400 Pixel (22706100 Bytes)

Opis:

This is an illustration of the life cycle of Strongyloides stercoralis, the causal agent of Strongyloidiasis. The Strongyloides stercoralis life cycle is complex, alternating between free-living and parasitic cycles and involving autoinfection. In the free-living cycle: Rhabditiform larvae are passed in the stool of an infected definitive host image , develop into either infective filariform larvae (direct development) image or free-living adult males and females image that mate and produce eggs image , from which rhabditiform larvae hatch image and eventually become infective filariform (L3) slarvae image . The filariform larvae penetrate the human host skin to initiate the parasitic cycle (see below) image . This second generation of filariform larvae cannot mature into free-living adults and must find a new host to continue the life cycle.

Parasitic cycle: Filariform larvae in contaminated soil penetrate human skin when skin contacts soil image , and migrate to the small intestine image . It has been thought that the L3 larvae migrate via the bloodstream and lymphatics to the lungs, where they are eventually coughed up and swallowed. However, L3 larvae appear capable of migrating to the intestine via alternate routes (e.g. through abdominal viscera or connective tissue). In the small intestine, the larvae molt twice and become adult female worms image . The females live embedded in the submucosa of the small intestine and produce eggs via parthenogenesis (parasitic males do not exist) image , which yield rhabditiform larvae. The rhabditiform larvae can either be passed in the stool image (see “Free-living cycle” above), or can cause autoinfection image .

Licencja:

Public domain