Editing Strongyloides stercoralis (section)

==Symptoms==
{{main|Strongyloidiasis}}
Many people infected are asymptomatic at first. Symptoms include [[dermatitis]]: swelling, itching, [[larva currens]], and mild hemorrhage at the site where the skin has been penetrated. Spontaneous scratch-like lesions may be seen on the face or elsewhere. If the parasite reaches the lungs, the chest may feel as if it is burning, and wheezing and coughing may result, along with pneumonia-like symptoms ([[Löffler's syndrome]]). The intestines could eventually be invaded, leading to burning pain, tissue damage, sepsis, and ulcers. Stools may have yellow [[mucus]] with a recognizable smell. Chronic [[diarrhea]] can be a symptom.<ref>{{cite journal|last1=Thamwiwat|first1=Alisa|last2=Mejia|first2=Rojelio|last3=Nutman|first3=Thomas B.|last4=Bates|first4=Jeffrey T.|title=Strongyloidiasis as a Cause of Chronic Diarrhea, Identified Using Next-Generation Strongyloides stercoralis-Specific Immunoassays|journal=Current Tropical Medicine Reports|date=6 July 2014|volume=1|issue=3|pages=145–147|doi=10.1007/s40475-014-0026-7|doi-access=free}}</ref> In severe cases, edema may result in obstruction of the intestinal tract, as well as loss of [[peristalsis|peristaltic]] contractions.<ref>{{cite book |last1=Roberts |first1=L. |last2=Janovy |first2=J. Jr. |title=Foundations of Parasitology |year=2005 |pages=414–415 |location=Boston |publisher=McGraw Hill |edition=7th |isbn=0071112715 }}</ref>

Strongyloidiasis in immunocompetent individuals is usually an indolent disease. However, in immunocompromised individuals, it can cause a hyperinfective syndrome (also called disseminated strongyloidiasis) due to the reproductive capacity of the parasite inside the host. This hyperinfective syndrome can have a mortality rate close to 90% if disseminated.<ref>{{cite journal|pmid=7025145|year=1981|last1=Igra-Siegman|first1=Y|last2=Kapila|first2=R|last3=Sen|first3=P|last4=Kaminski|first4=ZC|last5=Louria|first5=DB|title=Syndrome of hyperinfection with Strongyloides stercoralis|volume=3|issue=3|pages=397–407|journal=Reviews of Infectious Diseases|doi=10.1093/clinids/3.3.397}}</ref><ref name=HS>{{Cite journal 
| last1 = Marcos | first1 = L. A. 
| last2 = Terashima | first2 = A. 
| last3 = Dupont | first3 = H. L. 
| last4 = Gotuzzo | first4 = E. 
| title = Strongyloides hyperinfection syndrome: An emerging global infectious disease 
| doi = 10.1016/j.trstmh.2008.01.020 
| journal = Transactions of the Royal Society of Tropical Medicine and Hygiene 
| volume = 102 
| issue = 4 
| pages = 314–318 
| year = 2008 
| pmid = 18321548 
}}</ref><ref>{{cite journal|last1=Newberry|first1=AM|last2=Williams|first2=DN|last3=Stauffer|first3=WM|last4=Boulware|first4=DR|last5=Hendel-Paterson|first5=BR|last6=Walker|first6=PF|title=Strongyloides hyperinfection presenting as acute respiratory failure and gram-negative sepsis.|journal=Chest|date=Nov 2005|volume=128|issue=5|pages=3681–4|pmid=16304332|doi=10.1378/chest.128.5.3681|pmc=1941746}}</ref>

Immunosuppressive drugs, especially corticosteroids and agents used for tissue transplantation, can increase the rate of autoinfection to the point where an overwhelming number of larvae migrate through the lungs, which in many cases can prove fatal. In addition, diseases such as [[human T-lymphotropic virus 1]], which enhance the Th1 arm of the immune system and lessen the Th2 arm, increase the disease state.<ref name=HS/> Another consequence of autoinfection is the autoinfective larvae can carry gut bacteria back into the body. About 50% of people with hyperinfection present with bacterial disease due to enteric bacteria. Also, a unique effect of autoinfective larvae is larva currens due to the rapid migration of the larvae through the skin. Larva currens appears as a red line that moves rapidly (more than {{convert|5|cm|in|0|abbr=on|disp=or}} per day), and then quickly disappears. It is pathognomonic for autoinfective larvae and can be used as a diagnostic criterion for strongyloidiasis due to ''S. stercoralis''.