New Mexico confirms two more screwworm cases in a horse and a calf

New Mexico animal health officials confirmed two more cases of New World screwworm on Thursday, one in a horse and one in a calf in Grant County. The parasite's larvae feed on living flesh and can seriously hurt or kill livestock if wounds go untreated.

Zones and restrictions

Officials set up an infested zone with a radius of at least 12.4 miles around each affected animal. The two northernmost zones were joined into one larger area, which leaves two separate infested zones in the state. Animals inside the zones must be inspected and treated if needed before they move within or out of the area.

State and federal teams are widening surveillance and fly trapping around the sites to learn whether the pest has spread beyond the animals already found.

What owners should watch for

The state veterinarian asked animal owners to look closely for wounds that do not heal and injuries that keep getting worse. Other warning signs include maggots in a wound and a foul-smelling discharge. Anyone who suspects screwworm should call the New Mexico Livestock Board right away and avoid moving the animal.

New drugs cleared for use

The same day federal regulators published a notice authorizing emergency use of four animal drugs to prevent and treat screwworm infestations. The move gives veterinarians more tools as the outbreak response grows.

Agriculture Secretary Jeff Witte said early detection and quick reporting are critical to limiting the spread and thanked producers and veterinarians for working with agencies.