Recent Increase in Cases#
The U.S. Department of Agriculture (USDA) has reported 243 new cases of New World Screwworm for the week ending April 26, according to Raymond James. This represents a notable increase in weekly cases, which have been steadily rising since early March. Previously, the weekly count was in the low 100s, with increases of 10 to 20 cases. However, this week saw an alarming jump of nearly 50 new cases compared to the previous week.
Spread Towards the U.S. Border#
The New World Screwworm is moving closer to the U.S. border, with a new case reported in Coahuila, Mexico. This area is west of Nuevo Leon and Tamaulipas and lies outside the zone where sterile flies are being released to control the pest. Active cases are increasing in states that border Texas, including Tamaulipas, which has 132 active cases and 48 new cases reported this week, and Nuevo Leon, with 11 active cases and 3 new cases.
Impact on Cattle Imports#
The rise in New World Screwworm cases has led to a halt in U.S. cattle imports from Mexico, creating pressure on beef supplies over the past year. Cattle imports from Mexico accounted for about 4% of total U.S. cattle in 2024. The ongoing spread of the pest raises concerns about when these imports might resume, as there is a risk that it could eventually reach Texas, potentially restricting cattle movement and further impacting supplies.
Efforts to Combat the Spread#
Officials from the U.S. and Mexico are actively working to control the spread of New World Screwworm using a method called sterile insect technique. Currently, sterile flies are being dispersed from Moore Air Base. Recently, the FDA issued multiple Emergency Use Authorizations for medications aimed at preventing and treating New World Screwworm. Additionally, in mid-April, the USDA and the Army Corps of Engineers began construction on a new sterile fly production facility, expected to be operational by the end of 2027.