Index case (medicine)
Encyclopedia
The index case or primary case is the initial patient
in the population
of an epidemiological
investigation. The index case may indicate the source of the disease
, the possible spread, and which reservoir holds the disease in between outbreak
s. 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. "Patient Zero" was used to refer to the index case in the spread of HIV in North America.
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 and Prevention
(CDC). 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). The CDC identified Gaëtan Dugas
as the first person to bring HIV from Africa to the United States
and to introduce it to gay bathhouse
s.
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 Gaëtan Dugas. 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 seen as the original source of the HIV epidemic among homosexual men. Four years later, Darrow repudiated the study methodology and how Shilts had represented its conclusions.
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, 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.
begins with the account of the "Patient Zero" from which a zombie
pandemic
began. Brooks depicts a doctor's encounter with the first victim—a 12-year-old Chinese boy.
Patient
A patient is any recipient of healthcare services. The patient is most often ill or injured and in need of treatment by a physician, advanced practice registered nurse, veterinarian, or other health care provider....
in the population
Population
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
of an epidemiological
Epidemiology
Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...
investigation. The index case may indicate the source of the disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
, the possible spread, and which reservoir holds the disease in between outbreak
Outbreak
Outbreak is a term used in epidemiology to describe an occurrence of disease greater than would otherwise be expected at a particular time and place. It may affect a small and localized group or impact upon thousands of people across an entire continent. Two linked cases of a rare infectious...
s. 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. "Patient Zero" was used to refer to the index case in the spread of HIV in North America.
Gaëtan Dugas case ("Patient Zero")
In the early years of the AIDSAIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...
epidemic, there was controversy
Controversy
Controversy is a state of prolonged public dispute or debate, usually concerning a matter of opinion. The word was coined from the Latin controversia, as a composite of controversus – "turned in an opposite direction," from contra – "against" – and vertere – to turn, or versus , hence, "to turn...
about a so-called Patient Zero, who was the basis of a complex transmission scenario compiled by Dr. William Darrow
William Darrow
William "Bill" Darrow is a Professor of Public Health at Florida International University in Miami, Florida.Before accepting a position at FIU in August, 1994, Darrow served as Chief of the Behavioral and Prevention Research Branch, Division of STD/HIV Prevention, at the National Center for...
and colleagues at the U.S. Centers for Disease Control and Prevention
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...
(CDC). This epidemiological study showed how Patient Zero had infected multiple partners with HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
, and they, in turn, transmitted it to others and rapidly spread the virus to locations all over the world(Auerbach et al., 1984). The CDC identified Gaëtan Dugas
Gaëtan Dugas
Gaëtan Dugas was a Canadian who worked for Air Canada as a flight attendant. Dugas became notorious as the alleged patient zero for AIDS, though he is now more accurately regarded as one of many highly sexually active men who spread AIDS widely before the disease was identified.-Patient Zero...
as the first person to bring HIV from Africa to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and to introduce it to gay bathhouse
Gay bathhouse
Gay bathhouses, also known as gay saunas or steam baths, are commercial bathhouses for men to have sex with other men. In gay slang in some regions these venues are also known colloquially as "the baths" or "the tubs," and should not be confused with public bathing.Not all men who visit gay...
s.
Journalist Randy Shilts
Randy Shilts
Randy Shilts was a pioneering gay American journalist and author. He worked as a freelance reporter for both The Advocate and the San Francisco Chronicle, as well as for San Francisco Bay Area television stations....
subsequently wrote about Patient Zero, based on Darrow's findings, in his 1987 book And the Band Played On
And the Band Played On
And the Band Played On: Politics, People, and the AIDS Epidemic is a nonfiction book written by San Francisco Chronicle journalist Randy Shilts, published in 1987...
, which identified Patient Zero as Gaëtan Dugas. 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 seen as the original source of the HIV epidemic among homosexual men. Four years later, Darrow repudiated the study methodology and how Shilts had represented its conclusions.
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
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
to Haiti
Haiti
Haiti , officially the Republic of Haiti , is a Caribbean country. It occupies the western, smaller portion of the island of Hispaniola, in the Greater Antillean archipelago, which it shares with the Dominican Republic. Ayiti was the indigenous Taíno or Amerindian name for the island...
and then entered the United States around 1969, 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.
Patient Zero in Literature
Max Brooks's novel World War Z: An Oral History of the Zombie WarWorld War Z
World War Z: An Oral History of the Zombie War is a 2006 post-apocalyptic horror novel by Max Brooks. It is a follow-up to his 2003 book The Zombie Survival Guide. Rather than a grand overview or narrative, World War Z is a collection of individual accounts in the form of first-person anecdote...
begins with the account of the "Patient Zero" from which a zombie
Zombie apocalypse
A zombie apocalypse is a particular scenario of apocalyptic literature that customarily has a science fiction/horror rationale. In a zombie apocalypse, a widespread rise of zombies hostile to human life engages in a general assault on civilization....
pandemic
Pandemic
A pandemic is an epidemic of infectious disease that is spreading through human populations across a large region; for instance multiple continents, or even worldwide. A widespread endemic disease that is stable in terms of how many people are getting sick from it is not a pandemic...
began. Brooks depicts a doctor's encounter with the first victim—a 12-year-old Chinese boy.
Other index patients
- Mary MallonMary MallonMary Mallon , also known as Typhoid Mary, was the first person in the United States identified as an asymptomatic carrier of the pathogen associated with typhoid fever. She was presumed to have infected some 53 people, three of whom died, over the course of her career as a cook...
(a.k.a. Typhoid Mary) was an index case of a typhoid outbreak. An apparently healthy carrier, she infected 47 people while working as a cookCook (profession)A cook is a person who prepares food for consumption. In Germany, Austria, Switzerland and Canada this profession requires government approval ....
. She eventually was quarantineQuarantineQuarantine is compulsory isolation, typically to contain the spread of something considered dangerous, often but not always disease. The word comes from the Italian quarantena, meaning forty-day period....
d to prevent her from spreading the disease to others. - The first recorded victim of the Ebola virusEbola virusEbola virus causes severe disease in humans and in nonhuman primates in the form of viral hemorrhagic fever. EBOV is a Select Agent, World Health Organization Risk Group 4 Pathogen , National Institutes of Health/National Institute of Allergy and Infectious Diseases Category A Priority Pathogen,...
was a 44-year-old schoolteacher named Mabalo Lokela, who died 8 September 1976, 14 days after symptom onset. - 64-year-old Liu Jianlun, a GuangdongGuangdongGuangdong is a province on the South China Sea coast of the People's Republic of China. The province was previously often written with the alternative English name Kwangtung Province...
doctor, transmitted SARSSevere acute respiratory syndromeSevere Acute Respiratory Syndrome is a respiratory disease in humans which is caused by the SARS coronavirus . Between November 2002 and July 2003 an outbreak of SARS in Hong Kong nearly became a pandemic, with 8,422 cases and 916 deaths worldwide according to the WHO...
during a stay in the Hong KongHong KongHong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...
Metropole Hotel in 2003. - A baby in the Lewis House at 40 Broad Street is considered the index patient in the 1854 cholera outbreak1854 Broad Street cholera outbreakThe Broad Street cholera outbreak was a severe outbreak of cholera that occurred near Broad Street in Soho district of London, England in 1854...
in the Soho neighborhood of London. (The Ghost MapThe Ghost MapThe Ghost Map: The Story of London's Most Terrifying Epidemic - and How it Changed Science, Cities and the Modern World is a book by Steven Berlin Johnson in which he describes the most intense outbreak of cholera in Victorian London - and what it means to us today, from the way we understand...
, Steven Johnson, 2005) - Édgar Enrique Hernández may be patient zero of the 2009 swine flu outbreak. He recovered, and a bronze statue may be erected in his honor. Maria Adela Gutierrez, who contracted the virus about the same time as Hernández, became the first officially confirmed fatality.