Flesh-eating screwworm detected 25 miles from U.S. border, USDA says A flesh-eating New World screwworm has been detected in Mexico, just 25 miles from the U.S. border, marking the closest proximity to U.S. soil in recent times. While the USDA states the current risk to the U.S. remains low, cases have been increasing in Mexico, with the parasite laying eggs in wounds of warm-blooded animals and people. The screwworm, typically found in South America and the Caribbean, has been migrating northwards.

• A New World screwworm was found in a goat in Mexico’s Coahuila state, 25 miles from the U.S. border.
• This is the closest the screwworm has been detected to U.S. soil since at least September.
• The U.S. Department of Agriculture monitors cases in Mexico and notes the pest is not currently present in the U.S. with a very low risk.
• The parasitic fly feeds on warm-blooded animals and people, laying eggs in open wounds or orifices.
• In the past year, the first human case of screwworm infestation was confirmed in a traveler returning to Maryland from El Salvador.