A case of New World screwworm has been confirmed in South Texas, marking the first detected breach of the US-Mexico border by these flesh-eating flies. Agriculture Secretary Brooke Rollins confirmed that a three-week-old calf in Zavala County tested positive for the infection.

Despite the serious threat to livestock, there have been disputes over detections within the US. State representative Don McLaughlin claimed a case was found just one mile from the border, but USDA officials denied this claim, citing it as causing significant panic among the public and media.

The screwworm poses a grave danger to animals by laying hundreds of eggs in wounds or openings, allowing larvae to feed on living tissue. The parasite has been contained since the 1960s through concerted eradication efforts, but recent breaches have seen the fly inch closer to the US border.

To combat this threat, the USDA is setting up a unified Incident Command Team and implementing quarantine measures in Zavala County. Sterile insect technique will also be employed, with 4 million flies being released per week in the area by air, and more to be released via ground chambers.