Editing Encephalitis (section)

===Viral===
{{main|Viral encephalitis|Herpesviral encephalitis}}
Viral infections are the usual cause of infectious encephalitis.<ref name=":1" /> Viral encephalitis can occur either as a direct effect of an acute [[infection]], or as one of the [[sequelae]] of a [[latent infection]]. The majority of viral cases of encephalitis have an unknown cause; however, the most common identifiable cause of viral encephalitis is from [[herpes simplex]] infection.<ref>{{Cite book |title=Harrison's Principles of Internal Medicine |vauthors=Roos KL, Tyler KL |date=2015 |publisher=McGraw-Hill Education |isbn=978-0-07-180215-4 |edition=19 |location=New York, NY |chapter=Meningitis, Encephalitis, Brain Abscess, and Empyema |access-date=2017-11-17 |chapter-url=http://accessmedicine.mhmedical.com/content.aspx?bookid=1130&sectionid=79734335 |archive-url=https://web.archive.org/web/20171117122546/http://accessmedicine.mhmedical.com/content.aspx?bookid=1130&sectionid=79734335 |archive-date=2017-11-17 |url-status=live}}</ref> Other causes of acute viral encephalitis are [[rabies virus]], [[poliovirus]], and [[measles virus]].<ref>{{Cite journal |vauthors=Fisher DL, Defres S, Solomon T |date=March 2015 |title=Measles-induced encephalitis |journal=QJM |volume=108 |issue=3 |pages=177–182 |doi=10.1093/qjmed/hcu113 |pmid=24865261 |doi-access=free}}</ref>

Additional possible viral causes are [[Arbovirus|arboviral]] [[flavivirus]] ([[Saint Louis encephalitis|St. Louis encephalitis]], [[West Nile virus]]), [[bunyavirus]] (La Crosse strain), [[arenavirus]] (lymphocytic choriomeningitis virus), [[Reoviridae|reovirus]] (Colorado tick virus), and [[henipavirus]] infections.<ref>{{cite journal |last1=Kennedy |first1=P. G. E. |title=Viral encephalitis: causes, differential diagnosis, and management |journal=Journal of Neurology, Neurosurgery, and Psychiatry |date=March 2004 |volume=75 Suppl 1 |issue=Suppl 1 |pages=i10–15 |doi=10.1136/jnnp.2003.034280 |pmid=14978145 |pmc=1765650 }}</ref><ref>{{Cite book |title=Henipavirus |vauthors=Broder CC, Geisbert TW, Xu K, Nikolov DB, Wang LF, Middleton D, Pallister J, Bossart KN |year=2012 |isbn=978-3-642-29818-9 |series=Current Topics in Microbiology and Immunology |volume=359 |pages=197–223 |chapter=Immunization strategies against henipaviruses |doi=10.1007/82_2012_213 |pmc=4465348 |pmid=22481140}}</ref> The [[Powassan virus]] is a rare cause of encephalitis.<ref>{{Cite web |date=4 December 2018 |title=Symptoms & Treatment {{!}} Powassan {{!}} CDC |url=https://www.cdc.gov/powassan/symptoms.html |url-status=live |archive-url=https://web.archive.org/web/20190626032132/https://www.cdc.gov/powassan/symptoms.html |archive-date=26 June 2019 |access-date=26 June 2019 |website=www.cdc.gov |language=en-us}}</ref>