Screwworms are on their way to becoming a billion-dollar international problem but can be contained if ranchers are vigilant, watch their herds and other wildlife, and quickly treat any infestations, U.S. Agriculture Secretary Brooke Rollins said.

Concerns over the spread of the New World screwworm are growing after multiple new cases were confirmed on Monday, and as state and federal officials ramp up efforts to contain the parasite.

Concerns over the spread of the New World screwworm are growing after multiple new cases were confirmed on Monday, and as state and federal officials ramp up efforts to contain the parasite.

The New World screwworm fly is threatening the $113 billion U.S. cattle industry for the first time in more than a half century, with an infestation from its flesh-eating larvae confirmed in south Texas.