Index case explained

The index case or patient zero is the first documented patient in a disease epidemic within a population,[1] or the first documented patient included in an epidemiological study.[2] It can also refer to the first case of a condition or syndrome (not necessarily contagious) to be described in the medical literature, whether or not the patient is thought to be the first person affected. An index case can achieve the status of a "classic" case study in the literature, as did Phineas Gage, the first known person to exhibit a definitive personality change as a result of a brain injury.[3]

Term

The index case may or may not indicate the source of the disease, the possible spread, or which reservoir holds the disease in between outbreaks, but may bring awareness of an emerging outbreak. Earlier cases may or may not be found and are labeled primary or coprimary, secondary, tertiary, etc.[4] The term primary case can only apply to infectious diseases that spread from human to human, and refers to the person who first brings a disease into a group of people.[5] In epidemiology, the term is often used by both scientists and journalists alike to refer to the individual known or believed to have been the first infected or source of the resulting outbreak in a population as the index case, but such would technically refer to the primary case.[6]

Origin of patient zero

"Patient zero" was used to refer to the supposed source of HIV outbreak in the United States, flight attendant Gaëtan Dugas in the popular press, but the term's use was based on a misunderstanding (and Dugas was not the index case).[7] In the 1984 study of Centers for Disease Control and Prevention (CDC), one of the earliest recorded HIV-patients was code-named "patient O", which stands for "patient out of California". The letter O, however, was interpreted by some readers of the report as the numeral 0. The designation patient zero (for Gaëtan Dugas) was subsequently propagated by the San Francisco Chronicle journalist Randy Shilts in his book And the Band Played On in 1987. William Darrow, behavioral scientist of CDC responsible to figure out why gay men in Los Angeles were dying of a strange illness, said: "That's correct. I never labeled him Patient Zero".[8]

The term has been expanded into general usage to refer to an individual identified as the first carrier of a communicable disease in a population (the primary case) or pandemics, or the first incident in the onset of a catastrophic trend.[9] [10] In some cases, a known or suspected patient zero may be informally referred to as an index case for the purpose of a scientific study, such as the two-year-old boy in a remote village in Guinea who was thought to be the source of the largest Ebola virus outbreak in history,[11] or an unknown one, such as the mysterious patient zero of COVID-19.[12] [13]

In genetics, the index case is the case of the original patient (i.e. propositus or proband) that stimulates investigation of other members of the family to discover a possible genetic factor.[14]

The term can also be used in non-medical fields to describe the first individual affected by something negative that since propagated to others, such as the first user on a network infected by malware.

Examples

Gaëtan Dugas

In the early years of the AIDS epidemic, a patient zero transmission scenario was compiled by William Darrow and colleagues at the United States Centers for Disease Control and Prevention (CDC). This epidemiological study showed how patient zero had infected multiple partners with HIV, and they, in turn, transmitted it to others causing rapid spread of the virus to locations all over the world (Auerbach et al., 1984). The CDC identified Gaëtan Dugas as a carrier of the virus from Europe to the United States, who spread it to other men he had sexual contact with at gay bathhouses.[15]

Journalist Randy Shilts subsequently wrote about patient zero, based on Darrow's findings, in his 1987 book And the Band Played On, which identified patient zero as being Gaëtan Dugas.[16] Dugas was a flight attendant who was sexually promiscuous in several North American cities, according to Shilts' book. He was vilified for several years as a "mass spreader" of HIV, and was seen as the original source of the HIV epidemic among homosexual men. Four years later, Darrow repudiated the study's methodology and how Shilts had represented its conclusions.[17]

A 2007 study by Michael Worobey and Arthur Pitchenik published in the Proceedings of the National Academy of Sciences of the United States of America claimed that, based on the results of genetic analysis, current North American strains of HIV probably moved from Africa to Haiti before entering the United States around 1969,[18] probably through a single immigrant. However, a teenager named Robert Rayford died in St. Louis, Missouri, possibly of complications from AIDS in 1969, having most likely become infected with the virus before 1966. This would imply that there were prior carriers of HIV-strains in North America.[19] [20]

The phrase patient zero is now used in the media to refer to the primary case for infectious disease outbreaks, as well as for computer virus outbreaks, and more broadly, as the source of ideas or actions that have far-reaching consequences.[21] [22] [23] [24] [25]

David Heymann, professor of Infectious Disease Epidemiology at the London School of Hygiene & Tropical Medicine, and formerly with the World Health Organization (WHO),[26] has questioned the importance of finding patient zero, stating, "Finding patient zero may be important in some instances, but only if they are still alive and spreading the disease; and more often than not, especially in large disease outbreaks, they're not."[27]

Others

Non-medical usage

The term is used to identify the first computer or user to be infected with malware on a network, which then infected other systems.[39] [40]

Monica Lewinsky has described herself as the "patient zero" of online harassment, meaning that she was the first person to receive widespread public harassment via the internet.[41]

See also

External links

Notes and References

  1. Web site: Diseases – Activity 1 – Glossary, page 3 of 5 . science.education.nih.gov . 2017-11-10 . 2017-11-10 . https://web.archive.org/web/20171110171941/https://science.education.nih.gov/supplements/webversions/InfectiousDiseases/other/glossary/act1-gloss3.html#i . live .
  2. Web site: WordNet Search – 3.0 . Princeton University, wordnetweb.princeton.edu . 3 November 2010 . 3 March 2012 . https://web.archive.org/web/20120303172910/https://wordnetweb.princeton.edu/perl/webwn?s=index%20case . live .
  3. News: Why Brain Scientists Are Still Obsessed With The Curious Case Of Phineas Gage. NPR.org. 2017-11-18. en. 2019-08-28. https://web.archive.org/web/20190828100239/https://www.npr.org/sections/health-shots/2017/05/21/528966102/why-brain-scientists-are-still-obsessed-with-the-curious-case-of-phineas-gage. live.
  4. Web site: Sporadic STEC O157 Infection: Secondary Household Transmission in Wales . Centers for Disease Control and Prevention, USA . CDC.gov . 1 January 1994 . 3 November 2010 . 28 May 2010 . https://web.archive.org/web/20100528175452/https://www.cdc.gov/ncidod/eid/vol4no4/parry.htm . live .
  5. Giesecke. Johan. Primary and index cases. The Lancet. 384. 9959. 2024. 10.1016/s0140-6736(14)62331-x. 25483164. 2014. 12454399.
  6. en-US. 2017-11-18.
  7. News: Gaétan Dugas: 'patient zero' not source of HIV/Aids outbreak, study confirms. Nicola. Davis. 27 October 2016. The Guardian. 26 October 2016. 27 October 2016. https://web.archive.org/web/20161027000213/https://www.theguardian.com/science/2016/oct/26/patient-zero-gaetan-dugas-not-source-of-hivaids-outbreak-study-proves. live.
  8. News: DOUCLEFF . MICHAELEEN . Researchers Clear 'Patient Zero' From AIDS Origin Story . 1 May 2021 . NPR . October 26, 2016 . 30 April 2021 . https://web.archive.org/web/20210430122054/https://www.npr.org/sections/health-shots/2016/10/26/498876985/mystery-solved-how-hiv-came-to-the-u-s . live .
  9. Web site: Patient Zero – definition of Patient Zero in the Medical dictionary – by the Free Online Medical Dictionary, Thesaurus and Encyclopedia . medical-dictionary.thefreedictionary.com . 3 November 2010 . 24 February 2021 . https://web.archive.org/web/20210224083623/https://medical-dictionary.thefreedictionary.com/Patient+Zero . live .
  10. Web site: patient zero Definition of patient zero in English by Oxford Dictionaries. Oxford Dictionaries English. 2017-11-18. 2017-12-01. https://web.archive.org/web/20171201044041/https://en.oxforddictionaries.com/definition/patient_zero. dead.
  11. News: Ebola outbreak: 'Patient zero' at start of deadly virus spread. 2014-08-11. The Independent. 2017-11-18. en-GB. 2017-12-01. https://web.archive.org/web/20171201041743/https://www.independent.co.uk/news/world/africa/ebola-outbreak-patient-zero-at-start-of-deadly-virus-spread-identified-by-scientists-as-a-two-year-9660864.html. live.
  12. News: Page J, Hinshaw D, McKay B . In Hunt for Covid-19 Origin, Patient Zero Points to Second Wuhan Market – The man with the first confirmed infection of the new coronavirus told the WHO team that his parents had shopped there . 26 February 2021 . . 27 February 2021 .
  13. News: Duarte F . 24 February 2020. As the cases of coronavirus increase in China and around the world, the hunt is on to identify "patient zero".. BBC News. 22 March 2020.
  14. Web site: Definition of index case. The free medical dictionary by farlex. 2013-05-11. 2013-05-12. https://web.archive.org/web/20130512051624/https://medical-dictionary.thefreedictionary.com/index+case. live.
  15. Pence, G. E. (2008). Preventing the Global Spread of AIDS. In Medical Ethics Accounts of the Cases That Shaped and Define Medical Ethics (p. 331). New York, USA, McGraw-Hill.
  16. https://andrejkoymasky.com/liv/fam/biod3/duga1.html Matt & Andrej Koymasky - Famous GLTB - Gaëtan Dugas
  17. Web site: The Origin of HIV and the First Cases of AIDS. AVERT. avert.org. 2010-11-03. 2010-11-04. https://web.archive.org/web/20101104215824/https://www.avert.org/origin-aids-hiv.htm. live.
  18. News: Key HIV strain 'came from Haiti'. BBC News. 2007-10-30. 2010-05-05. Neil. Bowdler. 2012-05-21. https://web.archive.org/web/20120521084500/https://news.bbc.co.uk/2/hi/health/7068574.stm. live.
  19. Web site: HIV Spread from Haiti to NYC in 1970 . The Scientist . 2021-07-10 . 2021-07-10 . https://web.archive.org/web/20210710141320/https://www.the-scientist.com/daily-news/hiv-spread-from-haiti-to-nyc-in-1970-patient-zero-not-to-blame-32644 . live .
  20. Worobey, Michael et al "1970s and 'Patient 0' HIV-1 genomes illuminate early HIV/AIDS history in North America" Nature (2016) doi:10.1038/nature19827
  21. News: Have Doctors Found Swine "Patient Zero?". CBS News. 2009-04-29. 2009-04-29. 2009-04-29. https://web.archive.org/web/20090429213725/https://www.cbsnews.com/stories/2009/04/29/earlyshow/main4976805.shtml. live.
  22. Web site: Researchers trawl for Conficker's 'Patient Zero' – Techworld.com. news.techworld.com. 2010-11-03. https://web.archive.org/web/20110718062248/https://news.techworld.com/security/113086/researchers-trawl-for-confickers-patient-zero/. 2011-07-18. dead.
  23. Web site: Patient Zero. TV.com. 2006-03-20. 2010-11-03. 2011-12-27. https://web.archive.org/web/20111227051609/https://www.tv.com/shows/law-order/patient-zero-276048. live.
  24. Web site: Lemos. Robert. Witty worm traced to 'Patient Zero'. The Register. 2017-08-10. 2017-08-10. https://web.archive.org/web/20170810135739/https://www.theregister.co.uk/2005/05/25/witty_worm_traced/. live.
  25. Web site: That Man in the White House. The Weekly Standard. 28 November 2003. 3 November 2010. 4 June 2011. https://web.archive.org/web/20110604094453/https://www.weeklystandard.com/Content/Public/Articles/000/000/003/437txvzt.asp?pg=2. live.
  26. Web site: WHO Members of, and Advisers to, the International Health Regulations (2005) Emergency Committee on Zika virus and observed increase in neurological disorders and neonatal malformations. WHO. 2019-12-25. 2019-04-21. https://web.archive.org/web/20190421202915/https://www.who.int/ihr/procedures/zika-ec-biographies/en/. live.
  27. Mohammadi. Dara. Finding patient zero. The Pharmaceutical Journal. 2015-01-15. 294. 7845. 2015-01-16. 2015-01-24. https://web.archive.org/web/20150124084210/https://www.pharmaceutical-journal.com/news-and-analysis/features/finding-patient-zero/20067543.article. live.
  28. Web site: NOVA | The Most Dangerous Woman in America | In Her Own Words . . 1938-11-11 . 2010-11-03 . 2010-04-26 . https://web.archive.org/web/20100426042928/https://www.pbs.org/wgbh/nova/typhoid/letter.html . live .
  29. Ebola haemorrhagic fever in Zaire, 1976 . Bull. World Health Organ. . 56 . 2 . 271–93 . 1978 . 307456 . 2395567 . dead . https://web.archive.org/web/20140808213715/https://whqlibdoc.who.int/bulletin/1978/Vol56-No2/bulletin_1978_56%282%29_271-293.pdf . 8 August 2014 . dmy-all . 22 May 2018 . Report of an International Commission .
  30. How SARS changed the world in less than six months . . 2003 . 81 . 8 . 2011-10-18 . 2012-04-05 . https://web.archive.org/web/20120405125444/https://www.scielosp.org/pdf/bwho/v81n8/v81n8a14.pdf . live .
  31. News: One family went on holiday – and made Toronto a global pariah . . London . 2003-04-24 . 2010-05-05 . Jeremy . Laurance . 2018-05-22 . https://web.archive.org/web/20180522183931/https://www.independent.co.uk/news/science/one-family-went-on-holiday-and-made-toronto-a-global-pariah-116428.html . live .
  32. Web site: Molecular Interventions – CLOCKSS. 14 October 2014.
  33. Web site: Have Doctors Found Swine "Patient Zero?" . . 2009-04-29 . 2010-11-03 . 2011-08-05 . https://web.archive.org/web/20110805043811/https://www.cbsnews.com/stories/2009/04/29/earlyshow/main4976805.shtml . live .
  34. Web site: Statue erected of first boy in world who caught swine flu. Mirror. mirror.co.uk. 2009-04-25. 2014-05-22. https://web.archive.org/web/20140522075428/https://www.mirror.co.uk/news/uk-news/statue-erected-of-first-boy-in-world-408563. live.
  35. News: Finding Ebola's 'patient zero'. The Guardian. 28 November 2014. 2014-10-28. Beukes. Suzanne. 2014-12-19. https://web.archive.org/web/20141219224429/https://www.theguardian.com/world/2014/oct/28/ebola-virus-guinea-first-victim-patient-zero. live.
  36. Book: Feldinger, Frank . A slight epidemic : the government cover-up of black plague in Los Angeles : what happened and why it matters . 2008 . Los Angeles, CA : Silver Lake Pub. . 978-1-56343-885-1 . 124–130.
  37. Web site: "I'm back in action," One of the first Americans who contracted COVID-19 speaks about his recovery. 13 March 2021.
  38. Web site: Who is 'patient zero' in the coronavirus outbreak?. Fernando. Duarte. www.bbc.com.
  39. News: Search for patient zero: uncovering malware infection at the source. 31 March 2017. Infosecurity Magazine. 10 July 2012. "Medical researchers look for patient zero to find out where a virus outbreak started and what places and people patient zero came into contact with in order to contain the outbreak and prevent further infections. Similarly, infosec researchers need to look for the user who first introduced the malware into the network, which application was carrying the malware, and the files that are causing it to spread in order to contain it, eliminate it, and prevent reinfection, explained Huger, vice president of development at Sourcefire's cloud technology group.". 31 March 2017. https://web.archive.org/web/20170331204928/https://www.infosecurity-magazine.com/news/search-for-patient-zero-uncovering-malware/. live.
  40. News: Savitz. Eric. Finding Patient Zero: The Key To Responding To Malware Attacks. 31 March 2017. Forbes. 5 June 2012. "In the physical world, the first thing researchers look for during an outbreak is patient zero. Where did the virus start and where are all of the places and who are all of the people it could have touched? In the cyber world this almost never happens. But it is just as fundamental.". 31 March 2017. https://web.archive.org/web/20170331121229/https://www.forbes.com/sites/ericsavitz/2012/06/05/finding-patient-zero-the-key-to-responding-to-malware-attacks/#1aace8ecf390. live.
  41. News: Lewinsky makes emotional plea to end cyberbullying . Merica . Dan . October 21, 2014 . . October 22, 2014 . October 22, 2014 . https://web.archive.org/web/20141022080457/https://www.cnn.com/2014/10/20/politics/lewinsky-cyber-bullying/index.html . live .

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Index case".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2024, A B Cryer, All Rights Reserved. Cookie policy.