Patient Zero | Radiolab Podcast

Episode Overview

• Originally produced in 2011 and introduced by Radiolab Executive Editor Soren Wheeler with co-hosts Jad Abumrad and Robert Krulwich, this episode investigates how massive social traumas, pandemics, and cultural trends begin, questioning whether we can truly trace them back to a single "Patient Zero" or original source ("the first cause" / "the 'but for'").
• The narrative begins with the historical investigation of Mary Mallon ("Typhoid Mary"), exploring the scientific discovery of asymptomatic, intermittent disease carriers and the psychological theater of public health quarantines.
• The episode then traces the origins of the HIV/AIDS pandemic, debunking the myth of flight attendant Gaëtan Dugas as "Patient Zero" and using evolutionary biology to rewind the viral genetic clock to a ~1908 primate spillover in southeastern Cameroon.
• Finally, the hosts examine cultural contagion through the competing origin stories, media hoaxes, and tragic personal histories behind the invention of the high-five, illustrating that both biological and cultural phenomena rarely have a single starting point.
• Note on disclosures: No financial sponsors, business ties, or funding disclosures are made during this broadcast, though several guests' books and a charity event are mentioned.

Key Concepts

• Asymptomatic and Intermittent Carriers (Typhoid Mary): University of Wisconsin Professor Emerita Judy Levitt (author of a book on Typhoid Mary), Columbia Public Health Professor David Rosner (who voices Mary Mallon's words), and Radiolab producer Sean Cole detail the 1906 Oyster Bay typhoid outbreak where a rich family's daughter, sister, mother, and maid got sick—6 out of 11 people in the house total. Sanitary engineer George Soper traced previous outbreaks across 1900 in Mamaroneck, 1902 in Dark Harbor, Maine, 1904 in Sands Point, New York (7 cases), Autumn 1906, and Winter 1907 in New York City to a single common denominator: Mary Mallon, a 36-year-old, 5'6", blond-haired, blue-eyed Irish immigrant cook whose famous Peach Melba (ice cream and raw, fresh peaches) did not cook off bacteria. Mary was North America's first documented "healthy carrier" (shedding live typhoid bacilli in her feces and urine with zero symptoms). While isolated on North Brother Island for 3 years, her feces were tested 3 times a week, revealing she was an "intermittent carrier" (testing positive sometimes and negative others). When Mary secretly sent her own stool samples to a private Manhattan lab, every single one came back negative. Released by a new health commissioner after signing an affidavit promising never to cook again, she returned to kitchen work at a restaurant, two hotels, an inn, a sanatorium, and a maternity hospital, causing an outbreak 5 years later and infecting at least 2 children. She was returned to North Brother Island, suffered a stroke, and spent the last 6 years of her life in a tuberculosis hospital ward before dying. Although hundreds of other healthy carriers (mostly men, some of whom were cooks who broke rules) were identified in New York, Mary was the only one permanently isolated, demonstrating how public health measures can prioritize the psychological comfort of scapegoating over consistent policy.
• Debunking the HIV "Patient Zero" Myth: Following the 1981 discovery of a syndrome affecting homosexual men in Los Angeles, archive news clips track the escalating toll from "more than 80 Americans," to "258 people," "625 people," and eventually "2.5 million people" infected by the time the movie And the Band Played On aired. Science writers Carl Zimmer (author of A Planet of Viruses) and David Quammen (author of Spillover), along with archive clips of CDC epidemiologist Dr. Selma Dritz, explain how the CDC interviewed about 30 gay male patients in New York, Los Angeles, and San Francisco to map sexual contacts. At the center of the diagram was "Number Zero" (with 7 or 8 lines emanating from him), birthing the term "Patient Zero." In his 1988 book And the Band Played On, reporter Randy Shilts identified Patient Zero as French-Canadian flight attendant Gaëtan Dugas, who slept with thousands of men. Scientists later debunked Dugas as the origin, pointing to earlier historical cases like a British sailor in 1959 (who died of Pneumocystis pneumonia) and a Chicago nurse in 1961 (who died of Kaposi's sarcoma).
• The Viral Genetic Clock: After HIV was isolated in 1984, scientists realized that because the virus mutates at a predictable rate when replicating, measuring genetic diversity among strains acts as a molecular clock. Zimmer, Quammen, and University of Arizona Evolutionary Biologist Michael Worobey explain that this clock proved HIV entered the US around 1966 (when Dugas was a virginal adolescent), tracing back to Haiti, and before that, Africa. Researchers unearthed the two earliest HIV-positive human specimens in Kinshasa (Democratic Republic of the Congo): ZR 59 (a blood tube from a Bantu man in 1959, unearthed in the late 1990s) and DRC 60 (human tissue preserved in paraffin wax from 1960, found by Worobey). Comparing the genetic differences between ZR 59 and DRC 60 allowed researchers to wind the clock back to their most recent common ancestor in 1908 (hedged by Quammen and Abumrad as "roughly," "give or take a margin of error," and "early 1900s").
• Primate SIV and the Cameroon Spillover: Around 1984, researchers at the New England Primate Research Center found Simian Immunodeficiency Virus (SIV) in macaque monkeys, and later in sooty mangabeys, African green monkeys, and mandrills—now totaling 40 different species of African monkeys with SIV. After researcher Martine Peeters in Gabon tested two orphan chimps and found the closest match to HIV-1, University of Pennsylvania Professor of Medicine and Microbiology Beatrice Hahn and her colleagues collected over 7,000 fecal samples from over 90 different wild chimp communities across Central Africa. In 2006, they published that HIV-1 came from a specific group of chimps penned in an approximately 100-square-mile area in southeastern Cameroon between the Boumba, Ngoko, and Sangha rivers.
• The "Cut Hunter" Hypothesis and Multiple Spillovers: Quammen explicitly hedges that reconstructing the exact moment of spillover is a hypothesis ("You can hypothesize. And the best hypothesis is the cut hunter hypothesis... If we had to guess, that human was probably a Bantu man..."). Around 1908, a hunter likely butchered a chimp and cut himself, allowing chimp blood to mix with human blood. Quammen notes that he "imagined" based on ground geography how a "Voyager" carried the virus down the Ngoko River, to the 200-meter-wide Sangha River, to the Congo River, arriving in the exploding colonial city of Brazzaville/Kinshasa (then Leopoldville) around 1920. Quammen states "there's really no way to know" why HIV spilled over in 1908 rather than thousands of years earlier, offering only possibilities like viral evolution versus colonial urbanization. Crucially, there are 12 major groups of the HIV virus, meaning at least 12 separate spillovers occurred (8 from monkeys, 3 from chimps, and 1 from gorillas, with Abumrad hedging that "It's probably happened dozens and dozens more times that we don't know about"). Only 1 of the 12—HIV-1 Group M—caused the global pandemic, infecting 60 million humans and killing 30 million (with estimates of 60 million dead by the end of the decade).
• Cultural Contagion and the High-Five: New York Times Magazine Contributing Writer Jon Mooallem explores the contested origins of the high-five. In 2007/2008, a press release claimed Murray State basketball player Lamont Sleets invented the gesture in the late 1970s/early 1980s after greeting his father's Vietnam War buddies from the "1st Battalion, 5th Infantry" (nicknamed "The Five") by saying "Hi, Five." Greg Harrell-Edge, co-founder of "National High-Five Day" and organizer of the "National High-Five-a-Thon" charity event, admits they completely fabricated the story as a prank to see if the media would run with it. Remarkably, Sleets' wife emailed the pranksters to say that only some of their details were wrong, and Sleets himself came to believe he probably did invent it.
• Competing Claims and Tragic Histories of the High-Five: Mooallem and Lutha Burke Davis (sister of former MLB player Glenn Burke) recount how on October 5, 1977 (Game 4 of the playoffs, Dodgers vs. Phillies), Dusty Baker hit a grand slam, and Glenn Burke raised his hand high and smacked Baker's hand at home plate—captured in a famous photograph. Burke (who had 17-inch biceps) was gay; Dodgers management offered him $75,000 to marry a woman. When Burke refused, he was traded to the Oakland A's, where coach Billy Martin introduced him as "Glenn Burke, the faggot." Burke retired within a year of his rookie season at around age 26, moved to San Francisco's Castro District, was hit by a car (breaking his leg in 3 places), became addicted to painkillers and crack, became homeless, was diagnosed with AIDS in 1994, and died in 1995. However, other origin claims exist: around 1979/1980, Louisville Cardinals basketball player Derek Smith told teammate Wiley Brown "No, up high" during practice, leading a broadcaster during the 1980 NCAA finals to explain the "high-five handshake" to America (Smith died suddenly of an undiagnosed heart condition on a cruise ship in 1996). Additionally, coach Kathy Gregory claims her 1960s women's volleyball teams high-fived constantly (especially when a player screwed up), and Radiolab producer Lynn Levy found two Frenchmen doing a high-five ("haut cinq") at 1 hour and 18 minutes into the 1955 (stated as 1955 by Krulwich) film Breathless.

Quotes

• At 14:35 - "I think it was more about making people feel safe than actually making them safe." - Radiolab producer Sean Cole explaining why public health officials permanently quarantined Mary Mallon on North Brother Island while allowing hundreds of other male healthy typhoid carriers to walk free in New York.
• At 20:20 - "And—and he gave HIV to a lot of people, there's no question about that. But what we do know is that he was not patient zero." - Science writer Carl Zimmer debunking the media narrative that flight attendant Gaëtan Dugas was the original source of the North American HIV epidemic.
• At 22:05 - "When it replicates within a single patient, it copies itself imprecisely. It mutates quickly. It changes a lot." - Science writer David Quammen explaining the biological mechanism that allows evolutionary biologists to use HIV's mutation rate as a molecular clock to date the virus's origins.
• At 25:44 - "Spillover is the term that scientists use to describe the moment when a virus in one species passes into another species." - David Quammen defining the foundational epidemiological concept behind zoonotic pandemics like HIV.
• At 28:58 - "There is no other virus that is any closer. So that's that." - University of Pennsylvania Professor Beatrice Hahn confirming that genetic testing of over 7,000 wild primate fecal samples definitively pinpointed the origin of HIV-1 to a specific chimpanzee community in southeastern Cameroon.
• At 34:00 - "So the spillover is not a highly improbable event. In most cases, those spillovers have not resulted in extended chains of disease in humans, let alone global pandemic." - David Quammen contextualizing the discovery of 12 separate SIV-to-HIV spillover groups, noting that only HIV-1 Group M triggered a global pandemic.
• At 44:19 - "Think about the feeling you get when you give someone the high-five. I had that feeling before everybody else did." - Writer Jon Mooallem quoting former MLB player Glenn Burke on the enduring pride Burke felt over his October 5, 1977 home-plate gesture with Dusty Baker, even as Burke's life ended in poverty and illness.
• At 49:29 - "Every time we look for the original of anything, be it a disease, a contagion, a gesture, we find more than one." - Co-host Robert Krulwich summarizing the central thesis of the episode after discovering multiple independent origins for typhoid outbreaks, HIV spillovers, and the high-five.

Takeaways

• Resist the urge to scapegoat individuals during public health crises: Recognize that fixating on a single "Patient Zero" (like Mary Mallon or Gaëtan Dugas) is often a psychological defense mechanism designed to make the public feel safe rather than an effective epidemiological strategy.
• Evaluate media origin stories with skepticism: As demonstrated by the fabricated Lamont Sleets press release for National High-Five Day—and the fact that Sleets himself came to believe the hoax—verify historical claims against primary sources rather than accepting convenient, viral narratives.
• Look for systemic conditions rather than single catalysts: Because biological spillovers (12 documented HIV groups) and cultural gestures (1955 French cinema, 1960s volleyball, 1970s baseball and basketball) happen repeatedly without catching on, focus your analysis on the environmental and social networks (such as colonial urbanization in 1920s Kinshasa or televised sports) that allow a single spark to scale into a global phenomenon.
• Communicate scientific uncertainty transparently: When reconstructing historical or biological events where direct observation is impossible, follow the example of researchers like David Quammen by explicitly separating hard data (like genetic mutation rates and fecal sample matches) from informed hypotheses (like the "cut hunter" and "Voyager" scenarios).
• Ensure public health policies are applied equitably: Audit containment and quarantine protocols to make sure marginalized individuals (such as an working-class immigrant woman like Mallon) are not subjected to harsher restrictions than the broader population of known disease carriers.