US scales up sterile fly release to combat New World screwworm threat amid ongoing eradication efforts

USDA has released more than one billion sterile flies as it intensifies efforts to contain New World screwworm in the southern US and Mexico. Around 100 million flies are now being dispersed each week, with the government working to substantially increase production capacity as livestock trade begins to resume.

The US Department of Agriculture says it has released more than 1bn sterile flies against New World screwworm, but Agriculture Secretary Brooke Rollins says eradication remains unfinished. The campaign matters far beyond Texas and New Mexico because a sustained resurgence could disrupt livestock movement, border trade and animal health controls across the southern US.

According to an RFD-TV report from Santa Teresa, New Mexico, Ms Rollins said USDA is currently dispersing about 100m sterile flies a week in Texas and Mexico. The technique, which helped eliminate screwworm from the US in the 1960s, works by flooding infested areas with sterile males so wild females produce no viable offspring.

The scale is still below the level USDA says is needed for full eradication. Officials have said production capacity in Panama, Mexico and a new Texas facility is intended to lift weekly output towards 500m flies. USDA also says surveillance has expanded, with more than 1,800 drone flights and monitoring of over 110,000 wild animals.

The outbreak has now reached 50 confirmed animal cases since June, including 48 in Texas and two in New Mexico. Some infested zones in Texas are beginning to lift, but federal officials still warn that the threat has not passed.