Livestock remain in pens before being exported to the U.S. through the Jeronimo-Santa Teresa border crossing, as the U.S. allowed Mexican cattle imports to resume after lifting a temporary suspension due to the detection of the New World screwworm, at the Chihuahua Regional Livestock Union facility, outside Ciudad Juarez, Mexico, February 10, 2025.
The screwworm, a pest whose maggots burrow into animal skin, causing severe and often fatal damage, affects livestock, wildlife, and, in rare cases, humans. The USDA halted cattle imports to address concerns about the pest’s northward movement. Speaking to Reuters at the World Organisation for Animal Health’s annual assembly in Paris, Sifford stated: “We want to make sure that we’re comfortable that the way that they’re doing surveillance gives us a good picture of what our risk level is for the fly continuing to move north.” She added: “It’s hard to say exactly when, but [imports will resume] for sure before the end of the year, unless something really dramatically changes.”
Sifford noted that no new screwworm cases have been reported farther north than one detected two weeks ago, approximately 700 miles from the U.S.-Mexico border. Mexico’s agriculture ministry confirmed on Tuesday that a USDA team will visit Mexico soon to assess the situation.
Sifford also addressed efforts to control highly pathogenic avian influenza, or bird flu, in U.S. dairy cows, setting a year-end deadline as the latest target for managing its spread. Since 2022, the virus has caused the loss of over 173 million chickens, turkeys, and other birds and has affected more than 1,000 dairy herds since 2024, according to USDA data. The U.S. Centers for Disease Control and Prevention reported that 70 people, mostly farm workers, have tested positive for the virus since 2024.
Sifford explained: “The only new [dairy] cases that we are seeing at this point are in states where we already have herds affected and are very much associated with biosecurity problems.” She expressed cautious optimism, stating: “I’m not sure if [a full halt] will happen by the summer, but we’re definitely on a steady path.”
For poultry, Sifford anticipated a quieter summer for bird flu outbreaks, as recent weeks have shown a decline in cases. She noted that wild birds, which can transmit the virus to poultry flocks, have not been a significant source of new infections. Sifford said: “We are not seeing introductions from wild birds, so we are expecting a quiet summer.”
