The New World screwworm fly has re-emerged in Texas, prompting the U.S. Department of Agriculture and state officials to launch containment efforts.
The parasite deposits flesh-eating maggots into livestock, which can lead to fatal infestations and significant economic losses for the beef industry. Because the parasite can spread rapidly, officials are prioritizing eradication to prevent a wider outbreak across the U.S. cattle population.
Reports of the outbreak surfaced earlier this month [1, 2]. The U.S. Department of Agriculture has confirmed six cases of the New World screwworm [3], while other reports indicate at least 12 animals have been found with the flesh-eating maggots [2]. This discrepancy reflects the ongoing process of identifying and verifying infected livestock in the field.
The re-emergence represents a significant threat to the cattle industry for the first time in more than 50 years [1]. The situation escalated in early June 2026 when a second infected calf was identified [4]. Following that discovery, Canada implemented a ban on cattle from Texas to prevent the parasite from crossing the border [4].
Livestock officials are coordinating a response between federal and Texas animal health authorities to isolate affected herds. The focus remains on preventing the parasite from establishing a permanent foothold in the region, a scenario that could jeopardize the stability of the North American beef market.
While some officials have said the current outbreak is not a threat, the history of the New World screwworm includes the destruction of entire herds [5]. The urgency of the current response is driven by the parasite's ability to cause rapid tissue decay in living animals, making early detection and aggressive eradication essential.
“The New World screwworm fly has re-emerged in Texas.”
The return of the New World screwworm threatens the biological security of the U.S. livestock industry. Because the parasite is highly invasive and lethal to cattle, the swift imposition of trade bans by partners like Canada demonstrates how a localized animal health crisis can quickly evolve into a broader economic disruption for international agricultural trade.
