Index case

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The index case or primary case is the initial patient in the population of an epidemiological investigation.^[1][2] The index case may indicate the source of the disease, the possible spread, and what reservoir holds the disease in between outbreaks. The index case is the first patient that indicates the existence of an outbreak. Earlier cases may be found and are labeled primary, secondary, tertiary, etc.^[3] "Patient Zero" was used to refer to the index case in the spread of HIV in North America.^[4]

Contents 1 Gaëtan Dugas case (Patient Zero) 2 Other Index Patients 3 See also 4 Notes 5 References 6 External links

[edit] Gaëtan Dugas case (Patient Zero)

In the early years of the AIDS epidemic, there was controversy about a so-called Patient Zero, who was the basis of a complex transmission scenario compiled by Dr. William Darrow and colleagues at the U.S. Centers for Disease Control (CDC).^[5] This epidemiological study showed how Patient Zero had infected multiple partners with HIV, and they, in turn, transmitted it to others and rapidly spread the virus to locations all over the world (Auerbach et al., 1984).

Journalist Randy Shilts subsequently wrote about Patient Zero, based on Darrow's findings,^[5] in his 1987 book And the Band Played On, which identified Patient Zero as Gaëtan Dugas.^[6] For several years, Dugas, a flight attendant who, according to Shilts' book, was sexually promiscuous in several North American cities, was vilified as a "mass spreader" of HIV and the original source of the HIV epidemic among gay men.^[5] Four years later, Darrow repudiated the study methodology and how Shiltz had represented its conclusions.^[5]

A 2007 study published in the Proceedings of the National Academy of Sciences by Michael Worobey and Dr. Arthur Pitchenik claimed that, based on the results of genetic analysis, HIV probably moved from Africa to Haiti and then entered the United States around 1969,^[7] probably through a single immigrant.

The term "Patient Zero" is now used in the media to refer to the index 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.^{[8][9][10][11][12]}

[edit] Other Index Patients

• Mary Mallon (a.k.a. Typhoid Mary) was a an index case for a typhoid outbreak. An apparently healthy carrier of typhoid, she infected 47 people while working as a cook. She eventually had to be quarantined to prevent her from spreading the disease to others.^[13]
• The first recorded case of the Ebola virus was a 44-year-old schoolteacher named Mabalo Lokela, who died 8 September, 1976, 14 days after symptom onset.^[14]
• 64-year-old Liu Jianlun, a Guangdong doctor, transmitted SARS during a stay in the Hong Kong Metropole Hotel in 2003.^[15]
• A baby in the Lewis House at 40 Broad Street is credited as being the index patient in the 1854 cholera outbreak in the Soho neighborhood of London. (The Ghost Map, Steven Johnson, 2005)^[16]
• Édgar Enrique Hernández, may be patient zero from the 2009 swine flu outbreak.^[17] He recovered, and a bronze statue may be erected in his honor.^[18] Maria Adela Gutierrez, who contracted the virus about the same time as Hernández, became the first officially confirmed fatality.

[edit] See also

• Proband
• HIV and AIDS misconceptions
• Mayinga N'Seka

[edit] Notes

1. ^ http://science.education.nih.gov/supplements/nih1/diseases/other/glossary/act1-gloss3.htm
2. ^ http://wordnetweb.princeton.edu/perl/webwn?s=index%20case
3. ^ http://www.cdc.gov/ncidod/EID/vol4no4/parry.htm
4. ^ http://medical-dictionary.thefreedictionary.com/Patient+Zero
5. ^ ^{a b c d} http://www.avert.org/origin-aids-hiv.htm
6. ^ Matt & Andrej Koymasky - Famous GLTB - Gaëtan Dugas
7. ^ BBC NEWS | Health | Key HIV strain 'came from Haiti'
8. ^ http://www.cbsnews.com/stories/2009/04/29/earlyshow/main4976805.shtml
9. ^ http://news.techworld.com/security/113086/researchers-trawl-for-confickers-patient-zero/
10. ^ http://www.tv.com/law-and-order/patient-zero/episode/276048/summary.html
11. ^ http://www.theregister.co.uk/2005/05/25/witty_worm_traced/
12. ^ http://www.weeklystandard.com/Content/Public/Articles/000/000/003/437txvzt.asp?pg=2
13. ^ http://www.pbs.org/wgbh/nova/typhoid/letter.html
14. ^ http://www.wadn.org/africa/?page_id=84
15. ^ http://www.independent.co.uk/news/science/one-family-went-on-holiday--and-made-toronto-a-global-pariah-595492.html
16. ^ http://molinterv.aspetjournals.org/content/7/4/224.full.pdf
17. ^ Have Doctors Found Swine "Patient Zero?"
18. ^ Politician’s Novel Idea for Mexican Tourism: Statue of Swine Flu Survivor

[edit] References

• Auerbach DM, Darrow WW, Jaffe HW, Curran JW. (1984) Cluster of cases of the acquired immune deficiency syndrome. Patients linked by sexual contact. Am J Med. 76, 487–492 PMID 6608269

[edit] External links

• The Centers for Disease Control (CDC) use [1] contact tracing & social network analysis to map recent TB outbreak from a patient zero in Oklahoma.
• Letter to the New York Review of Books (vol. 35, no. 19, December 8, 1988) by Dr. Andrew Moss, Dept. of Epidemiology and International Health, San Francisco, regarding the Patient Zero myth.