The US last officially reported an endemic infection in 1982. While travelers returning to the country have sometimes brought back the worms, the New World infection has recently reemerged in places it was once largely eradicated, posing a risk to human health, food security, and the livelihoods of local ranchers.

The parasite — the larva of the new world screwworm fly — can devastate cattle herds and is rife in parts of Central America.