screwworm

[ skroo-wurm ]
/ ˈskruˌwɜrm /

noun

the larva of any of certain flies of the genus Callitroga, which sometimes infests wounds and the nose and navel of domestic animals and humans.

Origin of screwworm

An Americanism dating back to 1875–80; screw + worm

British Dictionary definitions for screwworm

screwworm
/ (ˈskruːˌwɜːm) /

noun

the larva of a dipterous fly, Callitroga macellaria, that develops beneath the skin of living mammals often causing illness or death
the fly producing this larva: family Calliphoridae