Editing Infection (section)

===Disease===
[[Disease]] can arise if the host's protective immune mechanisms are compromised and the organism inflicts damage on the host. [[Microorganism]]s can cause tissue damage by releasing a variety of toxins or destructive enzymes. For example, ''[[Clostridium tetani]]'' releases a toxin that paralyzes muscles, and [[staphylococcus]] releases toxins that produce shock and [[sepsis]]. Not all infectious agents cause disease in all hosts. For example, less than 5% of individuals infected with [[polio]] develop disease.<ref>{{cite web |url=http://www.immunize.org/catg.d/p4215.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.immunize.org/catg.d/p4215.pdf |archive-date=2022-10-09 |title=Polio: Questions and Answers |website=immunize.org |access-date=9 July 2021 |url-status=live}}</ref> On the other hand, some infectious agents are highly virulent. The [[prion]] causing [[Bovine spongiform encephalopathy|mad cow disease]] and [[Creutzfeldt–Jakob disease]] invariably kills all animals and people that are infected.<ref>{{Cite journal |last=Trent |first=Ronald J |title=Infectious Diseases |date=2005 |journal=Molecular Medicine |pages=193–220 |doi=10.1016/B978-012699057-7/50008-4 |pmc=7149788|isbn=9780126990577 }}</ref>

Persistent infections occur because the body is unable to clear the organism after the initial infection. Persistent infections are characterized by the continual presence of the infectious organism, often as latent infection with occasional recurrent relapses of active infection. There are some viruses that can maintain a persistent infection by infecting different cells of the body. Some viruses once acquired never leave the body. A typical example is the herpes virus, which tends to hide in nerves and become reactivated when specific circumstances arise.<ref>{{Cite journal |last1=Rouse |first1=Barry T. |last2=Sehrawat |first2=Sharvan |date=2010 |title=Immunity and immunopathology to viruses: what decides the outcome? |journal=Nature Reviews Immunology |language=en |volume=10 |issue=7 |pages=514–526 |doi=10.1038/nri2802 |pmid=20577268 |pmc=3899649 |issn=1474-1741}}</ref>

Persistent infections cause millions of deaths globally each year.<ref>{{cite web |url=http://www.persistentinfection.net/ |title=Chronic Infection Information |website=persistentinfection.net |access-date=2010-01-14 |archive-url=https://web.archive.org/web/20150722065612/http://www.persistentinfection.net/ |archive-date=July 22, 2015}}</ref> Chronic infections by parasites account for a high morbidity and mortality in many underdeveloped countries.<ref>{{Cite journal|last1=Torgerson|first1=Paul R.|last2=Devleesschauwer|first2=Brecht|last3=Praet|first3=Nicolas|last4=Speybroeck|first4=Niko|last5=Willingham|first5=Arve Lee|last6=Kasuga|first6=Fumiko|last7=Rokni|first7=Mohammad B.|last8=Zhou|first8=Xiao-Nong|last9=Fèvre|first9=Eric M.|last10=Sripa|first10=Banchob|last11=Gargouri|first11=Neyla|date=2015-12-03|title=World Health Organization Estimates of the Global and Regional Disease Burden of 11 Foodborne Parasitic Diseases, 2010: A Data Synthesis|journal=PLOS Medicine|volume=12|issue=12|pages=e1001920|doi=10.1371/journal.pmed.1001920|issn=1549-1277|pmc=4668834|pmid=26633705 |doi-access=free }}</ref><ref>{{Citation|last1=Hotez|first1=Peter J.|title=Helminth Infections: Soil-transmitted Helminth Infections and Schistosomiasis|date=2006|url=http://www.ncbi.nlm.nih.gov/books/NBK11748/|work=Disease Control Priorities in Developing Countries|editor-last=Jamison|editor-first=Dean T.|edition=2nd|place=Washington (DC)|publisher=World Bank|isbn=978-0-8213-6179-5|pmid=21250326|access-date=2021-08-13|last2=Bundy|first2=Donald A. P.|last3=Beegle|first3=Kathleen|last4=Brooker|first4=Simon|last5=Drake|first5=Lesley|last6=de Silva|first6=Nilanthi|last7=Montresor|first7=Antonio|last8=Engels|first8=Dirk|last9=Jukes|first9=Matthew|editor2-last=Breman|editor2-first=Joel G.|editor3-last=Measham|editor3-first=Anthony R.|editor4-last=Alleyne|editor4-first=George|archive-date=2016-10-10|archive-url=https://web.archive.org/web/20161010040542/http://www.ncbi.nlm.nih.gov/books/NBK11748/|url-status=live}}</ref>