patient zero
noun
plural patient zeros also patient zeroes
: a person identified as the first to become infected with an illness or disease in an outbreak
The quest to find patient zero, the first person to contract the new virus, has revealed the first known case occurred in Wuhan …—
Susan Dunlevy
Susan Dunlevy
especially
: a person documented as being the first known case of a communicable disease in a particular population or region
Stay out of hospital emergency rooms unless you are severely ill or injured. For now, it's the likeliest place to catch coronavirus. Anyone unknowingly suffering from coronavirus is likely to go there. That's what "patient zero" in Italy did. —Betsy McCaughey
Betsy McCaughey The 26-year-old nurse contracted Ebola after volunteering to care for U.S. 'patient zero' Thomas Eric Duncan, who tragically died on October 10 from the deadly disease. —Ashley Collman et al.
compare index case sense 2
Ashley Collman et al. 
Examples of patient zero in a Sentence
Recent Examples on the Web
McConaughey appears to be patient zero for testing the theory while living in the middle of the United States.
—Nardine Saad, Los Angeles Times, 8 Mar. 2024
That could change if the lone mule deer that tested positive in Yellowstone National Park in November becomes patient zero in a local outbreak.
—Katie Hill, Outdoor Life, 4 Jan. 2024
The patient zero for the latest outbreak of the Ebola virus is believed to have been a person in a remote, mountainous area in southern Guinea, a country with just one doctor per 10,000 people.
—Jessica Hatcher, Foreign Affairs, 28 Apr. 2014
The major concern with these coronavirus clusters is that the patient zero spreads the illness beyond their household and inner circle and into the community.
—Selena Randhawa, refinery29.com, 20 Oct. 2020
For instance: Where is Huang Yanling, a lab employee widely rumored to be patient zero?
—Michael Brendan Dougherty, National Review, 7 Mar. 2023
Emile was patient zero in the worst Ebola outbreak the world has ever seen.
—Caroline Chen, ProPublica, 27 Feb. 2023
Nardine Saad, Los Angeles Times, 8 Mar. 2024
That could change if the lone mule deer that tested positive in Yellowstone National Park in November becomes patient zero in a local outbreak.
—Katie Hill, Outdoor Life, 4 Jan. 2024
The patient zero for the latest outbreak of the Ebola virus is believed to have been a person in a remote, mountainous area in southern Guinea, a country with just one doctor per 10,000 people.
—Jessica Hatcher, Foreign Affairs, 28 Apr. 2014
The major concern with these coronavirus clusters is that the patient zero spreads the illness beyond their household and inner circle and into the community.
—Selena Randhawa, refinery29.com, 20 Oct. 2020
For instance: Where is Huang Yanling, a lab employee widely rumored to be patient zero?
—Michael Brendan Dougherty, National Review, 7 Mar. 2023
Emile was patient zero in the worst Ebola outbreak the world has ever seen.
—Caroline Chen, ProPublica, 27 Feb. 2023
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'patient zero.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Word History
First Known Use
1987, in the meaning defined above
Dictionary Entries Near patient zero
Cite this Entry
“Patient zero.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/patient%20zero. Accessed 17 Apr. 2024.
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