Your body usually does a great job defending you from all kinds of viruses, fungi, and bacteria. However, there are some pathogens out there that can hide from your immune system and stay dormant in your body, waiting for their opportunity to strike. Hosted by: Hank Green ---------- Support SciShow by becoming a patron on Patreon: https://www.patreon.com/scishow ---------- Dooblydoo thanks go to the following Patreon supporters -- we couldn't make SciShow without them! Shout out to Bryce Daifuku, Kevin Bealer, Justin Lentz, Mark Terrio-Cameron, Patrick Merrithew, Accalia Elementia, Fatima Iqbal, Benny, Kyle Anderson, Mike Frayn, Tim Curwick, Will and Sonja Marple, Philippe von Bergen, Chris Peters, Kathy Philip, Patrick D. Ashmore, Thomas J., Charles George, Bader AlGhamdi. ---------- Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records: http://dftba.com/scishow ---------- Looking for SciShow elsewhere on the internet? Facebook: http://www.facebook.com/scishow Twitter: http://www.twitter.com/scishow Tumblr: http://scishow.tumblr.com Instagram: http://instagram.com/thescishow ---------- Sources: http://www.ncbi.nlm.nih.gov/books/NBK27090/ Varicella zoster: http://umm.edu/health/medical/altmed/condition/varicellazoster-virus http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3118253/ Measles virus: http://www.sciencemag.org/news/2015/01/what-does-measles-actually-do http://qjmed.oxfordjournals.org/content/108/3/177 http://pmj.bmj.com/content/78/916/63.long#ref-36 Human immunodeficiency virus: http://www.niaid.nih.gov/topics/hivaids/understanding/howhivcausesaids/pages/howhiv.aspx https://www.aids.gov/hiv-aids-basics/just-diagnosed-with-hiv-aids/hiv-in-your-body/stages-of-hiv/ http://cid.oxfordjournals.org/content/34/1/91.full Mycobacterium tuberculosis: http://www.hindawi.com/journals/jir/2012/139127/ http://www.tbfacts.org/tb/ https://www.niaid.nih.gov/topics/tuberculosis/Understanding/WhatIsTB/pages/detailed.aspx http://www.ufjf.br/imunologia/files/2009/05/21-de-junho-2012-Revisiting-the-role-of-the-granuloma-in.pdf Bacillus anthracis: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1769905/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2784286/ http://www.microbeworld.org/interesting-facts/how-do-they-do-that/microbial-spore-formation Toxoplasma gondii: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3488815/#CIT0011 http://www.cdc.gov/parasites/toxoplasmosis/biology.html