screwworm
noun
screw·worm
ˈskrü-ˌwərm 
1
: a blowfly (Cochliomyia hominivorax) of the warmer parts of America whose larva develops in sores or wounds or in the nostrils of mammals including humans with serious or sometimes fatal results
especially
: its larva
2
: any of several flies other than the screwworm and especially their larvae which parasitize the flesh of mammals
Examples of screwworm in a Sentence
Recent Examples on the Web
Europe Central America Australia Asia Answer: The parasite — the larva of the New World screwworm fly — is rife in parts of Central America.
—
Jana Kasperkevic, NBC news, 30 Aug. 2025
The larvae of the New World screwworm flies feed on living tissue, and mainly impact animals and livestock.
—Jenna Prestininzi, Freep.com, 26 Aug. 2025
This person has since recovered, and surveillance programs have not detected any screwworm flies in the surrounding areas.
—Dave Wessner, Forbes.com, 26 Aug. 2025
In the months since, the federal government has faced mounting pressure from agricultural groups worried about the threat of screwworm and its potential impact on the supply chain.
—Rachel Treisman, NPR, 25 Aug. 2025
One case in 2024 was in a Florida man who had traveled to the Dominican Republic and unknowingly had a screwworm fly lay eggs in his nose.
—Jon Brodkin, ArsTechnica, 25 Aug. 2025
By Jason Gale, Bloomberg The US has confirmed a case of the flesh-eating parasite New World screwworm in a person in Maryland, who had traveled from Guatemala and has received treatment for the infection, Reuters reported.
—Bloomberg, Mercury News, 25 Aug. 2025
Earlier this month, the FDA issued an Emergency Use Authorization (EUA) for animal drugs to treat or prevent infestations caused by screwworm.
—Youri Benadjaoud, ABC News, 25 Aug. 2025
The spread of the New World screwworm, a parasite that Mexico and the United States had eradicated decades ago, activated sanitary alarms and protection protocols in Mexico and the United States since late last year.
—Clara Migoya, AZCentral.com, 16 July 2025
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Jana Kasperkevic, NBC news, 30 Aug. 2025
The larvae of the New World screwworm flies feed on living tissue, and mainly impact animals and livestock.
—Jenna Prestininzi, Freep.com, 26 Aug. 2025
This person has since recovered, and surveillance programs have not detected any screwworm flies in the surrounding areas.
—Dave Wessner, Forbes.com, 26 Aug. 2025
In the months since, the federal government has faced mounting pressure from agricultural groups worried about the threat of screwworm and its potential impact on the supply chain.
—Rachel Treisman, NPR, 25 Aug. 2025
One case in 2024 was in a Florida man who had traveled to the Dominican Republic and unknowingly had a screwworm fly lay eggs in his nose.
—Jon Brodkin, ArsTechnica, 25 Aug. 2025
By Jason Gale, Bloomberg The US has confirmed a case of the flesh-eating parasite New World screwworm in a person in Maryland, who had traveled from Guatemala and has received treatment for the infection, Reuters reported.
—Bloomberg, Mercury News, 25 Aug. 2025
Earlier this month, the FDA issued an Emergency Use Authorization (EUA) for animal drugs to treat or prevent infestations caused by screwworm.
—Youri Benadjaoud, ABC News, 25 Aug. 2025
The spread of the New World screwworm, a parasite that Mexico and the United States had eradicated decades ago, activated sanitary alarms and protection protocols in Mexico and the United States since late last year.
—Clara Migoya, AZCentral.com, 16 July 2025
Cite this Entry
“Screwworm.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/screwworm. Accessed 29 Sep. 2025.
Copy CitationKids Definition
screwworm
noun
screw·worm
ˈskrü-ˌwərm
: the larva of a blowfly of the warm parts of America that develops in the wounds or sores of mammals and may cause disease or death
also
: the blowfly itself
Medical Definition
screwworm
noun
screw·worm
ˈskrü-ˌwərm
1
: either of two dipteran flies of the genus Cochliomyia:
a
: one (C. hominivorax) of the warmer parts of America whose larva develops in sores or wounds or in the nostrils of mammals including humans with serious or sometimes fatal results
especially
: its larva
2
: a dipteran fly of the genus Chrysomya (C. bezziana) that causes myiasis in Africa and southern Asia
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