contagious disease

noun

plural contagious diseases
: an infectious disease (such as influenza, measles, or tuberculosis) that is transmitted by contact with an infected individual or infected bodily discharges or fluids (such as respiratory droplets), by contact with a contaminated surface or object, or by ingestion of contaminated food or water

Note: The terms contagious disease and communicable disease are often used interchangeably. However, communicable diseases such as malaria or schistosomiasis that are spread by contact with disease vectors (such as mosquitoes or ticks) are not typically considered to be "contagious" diseases since they cannot be spread from direct contact with another person.

Examples of contagious disease in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Monarez’s testimony will come a day before the agency’s influential vaccine panel plans to vote on whether to delay or restrict access to shots that protect children against potentially serious contagious diseases. Christian Orozco, NBC news, 17 Sep. 2025 To prevent outbreaks of highly contagious diseases like measles, vaccination rates need to be as high as 95%. Miami Herald, 10 Sep. 2025 After Monarez's termination, resignation letters followed from CDC Chief Medical Officer Debra Houry and top officials for immunization and contagious diseases. Adrianna Rodriguez, USA Today, 4 Sep. 2025 Nine more measles cases have been reported in Oconto County, state health department data show, as the highly contagious disease continues its spread in Wisconsin, bringing the total in the county, and statewide, to 23. Madeline Heim, jsonline.com, 29 Aug. 2025 See All Example Sentences for contagious disease

Word History

First Known Use

1529, in the meaning defined above

Time Traveler
The first known use of contagious disease was in 1529

Cite this Entry

“Contagious disease.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/contagious%20disease. Accessed 22 Sep. 2025.

Medical Definition

contagious disease

noun
: an infectious disease (as influenza, measles, or tuberculosis) that is transmitted by contact with an infected individual or infected bodily discharges or fluids (as respiratory droplets), by contact with a contaminated surface or object, or by ingestion of contaminated food or water

Note: The terms contagious disease and communicable disease are often used interchangeably. However, communicable diseases (as malaria or schistosomiasis) that are spread by contact with disease vectors (as mosquitoes or ticks) are not typically considered to be "contagious" diseases since they cannot be spread from direct contact with another person.

More from Merriam-Webster on contagious disease

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