Photo courtesy of USDA’s Animal and Plant Health Inspection Service

The U.S. Department of Health and Human Services confirmed a human case of New World screwworm (NWS) in Maryland. The individual recently traveled to the U.S. from El Salvador. The person was diagnosed on August 4 by the Centers for Disease Control and Prevention (CDC). Authorities emphasized that the public health risk in the U.S. is very low.

South Dakota State Veterinarian Beth Thompson noted that once the infection was confirmed, the CDC worked with local physicians to remove the larvae. No livestock movement restrictions have been imposed, as NWS is not established in the U.S. However, it does remain endemic in parts of Central and South America.

This is not the first NWS case linked to international travel. Previous U.S. cases include a woman infected in the Dominican Republic in 2014, a man with a wound infection after travel to Argentina and Brazil in 2023, and an immunosuppressed patient in 2024 who returned from the Dominican Republic with a larval infestation. Additional cases have involved travelers from Peru and Colombia.

The National Cattlemen’s Beef Association (NCBA) assured livestock producers that protocols worked effectively. The case was identified quickly with coordination between the CDC, state departments of health, state animal officials and the USDA. NCBA CEO Colin Woodall reports there is no elevated risk to the livestock industry at this time.

Read more about the human case of New World Screwworm detected in Maryland here.