Deadly Screwworm Parasite Spreads Into Texas, Mystifying Health Experts

The deadly New World screwworm is spreading through Texas, creating a significant risk for the U.S. cattle herd. Health experts are puzzled by the parasite's arrival, as preventative measures have been in place. Livestock shipments from Mexico, where the screwworm's presence had recently accelerated, have been largely halted since the fly was confirmed there in late 2024.

Screwworm spread into Texas

• ▪The deadly New World screwworm is spreading through Texas.
• ▪The spread of the New World screwworm poses a significant risk to the US cattle herd.

Mexico livestock shipment halt

• ▪Livestock shipments from Mexico have been largely halted since late 2024.
• ▪The halt on Mexican livestock shipments began after the screwworm fly was confirmed in that country.
• ▪The screwworm’s presence had recently accelerated in Mexico before the country's livestock shipments were halted.

Origin mystery

• ▪Experts are puzzled over the mystery of how the New World screwworm got into Texas.

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