Following the news of New World screwworm being detected in Mexico in November 2024, USDA increased efforts to prevent the insect’s entry into the United States. Monitoring and mitigation practices were initiated, including the regular aerial introduction of sterile NWS insects in Mexico to curb population growth. The US swine industry considers NWS a potential emerging threat to swine health. Consequently, the Swine Health Information Center has shared regular NWS updates, held a webinar on the pest, and now makes a fact sheet available as a resource for swine producers and other industry stakeholders.
From the NWS fact sheet:
New World screwworm (NWS) is a parasitic fly whose larvae feed on the living tissue of warm-blooded animals including livestock, pets, wildlife, and people. Larval infestations (myiasis) can occur in any broken or damaged skin and cause rapidly progressing, painful wounds that can lead to serious injury or death. Although NWS was eradicated from the United States in the 1960s, the increasing number of confirmed cases in Central America and Mexico starting in late 2024 have renewed concern about risks to swine health, human safety, and farm profitability.
In Texas alone, projections estimate that an NWS outbreak could result in more than $1.8 billion in livestock losses (USDA APHIS, 2025). Due to significant animal health and economic impacts, suspected cases of NWS must be reported to state animal health officials and the USDA immediately. For comprehensive information regarding NWS, visit screwworm.gov.
Swine producers can prepare for NWS by understanding the fly’s behavior and life cycle, identifying production and housing conditions that increase risk of myiasis, implementing effective biosecurity, environmental, and wound management practices, knowing the response procedures for suspected infestations, and developing a NWS disaster management plan.
From the USDA’s screwworm.gov website:
Click here to see more...