What to know about the New World screwworm

Key Points:

• Texas is facing a resurgence of the New World screwworm, a flesh-eating parasitic fly larvae that damages warm-blooded animals, posing a significant threat to cattle, wildlife, and pets, with the first recent US case confirmed in early June in South Texas.
• The outbreak, originating in Central America in 2023, has caused over 185,000 animal cases and 2,100 human cases in Mexico and Central America, with 15 animal cases confirmed in the US so far, primarily in Texas, the nation's largest beef producer.
• The USDA and state governments are intensifying efforts to control the infestation through enhanced surveillance, quarantines, sterile fly release programs, and emergency use authorizations for treatments, while investing in new fly production facilities and innovative technologies.
• The screwworm was eradicated in the US by the 1960s using sterile insect techniques, but the current outbreak is attributed to failures in the Panama screwworm barrier, less effective sterile flies, and cross-border livestock movement, prompting criticism of government responses.
• Texas Governor Greg Abbott and state officials have declared a disaster, mobilized resources, and urged vigilance among producers and veterinarians to detect and report cases promptly, emphasizing the state's capacity to overcome the infestation as it did previously.