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

Since 1982, only a handful of cases have been documented, most notably in 2016 in the Florida Keys, when screwworm infected a deer population. —Connor Greene, CNN Money, 14 May 2025

New World screwworm flies cause myiasis, an infection of flesh-eating maggots that burrow into the skin of living animals, causing serious and often fatal damage, Reuters reported. —George Petras, USA Today, 14 May 2025

New World screwworms are parasitic larvae of the Cochliomyia hominivorax fly that can invade the tissues of any warm-blooded animal, including humans, according to the Associated Press (AP). —Adeola Adeosun gabe Whisnant, MSNBC Newsweek, 12 May 2025

Eradicating the disease is possible through a technique in which male screwworm flies are sterilized and then released into the environment to mate with females until the population dies out. —Youri Benadjaoud, ABC News, 12 May 2025

Female screwworm flies lay eggs in wounds or body openings of mammals, including cows, deer, birds, pets, and even humans, that can lead to a sometimes fatal infection. —Nicole Fallert, USA Today, 9 May 2025

In November 2024, cattle imports into the U.S. from Mexico were briefly suspended in response to New World screwworm fears. —Tommy Tuberville, Newsweek, 9 Jan. 2025

Cows are the screwworm’s favorite feast, but the maggots can also feed on other livestock as well as wildlife and pets. —Geraldine Castro, WIRED, 4 Dec. 2024

Livestock showing New World screwworm symptoms should be reported to the Texas Animal Health Commission or the U.S. Department of Agriculture. —Tommy Tuberville, Newsweek, 9 Jan. 2025

Word History

First Known Use

1846, in the meaning defined at sense 1

Kids 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

b

: secondary screwworm

2

: a dipteran fly of the genus Chrysomya (C. bezziana) that causes myiasis in Africa and southern Asia