Washington:  The United States has confirmed its first human case of the New World screwworm, a flesh-eating parasitic fly, marking a rare and significant public health development. The case involved a Maryland resident who had recently returned from El Salvador, a country currently experiencing an outbreak of the parasite. The Centers for Disease Control and Prevention (CDC) confirmed the diagnosis on August 4, 2025.

The New World screwworm, scientifically known as "Cochliomyia hominivorax", infests open wounds or body openings of warm-blooded animals, including humans. Its larvae feed on living tissue, which can cause severe damage and even be fatal if left untreated. While human cases are rare, the parasite poses a serious threat to livestock, particularly cattle, in affected regions.

Health officials emphasized that the risk to the general public in the United States remains very low, as the infection was acquired abroad and there is no evidence of local transmission. The patient has recovered, and investigations by the CDC and the Maryland Department of Health found no indication that the parasite spread to other individuals or animals.

The case has raised concerns about the potential spread of the parasite, especially with its resurgence in Central America. The U.S. Department of Agriculture has been monitoring the situation closely, implementing preventive measures such as suspending cattle imports from Mexico and releasing sterile male flies to control the screwworm population.

Authorities advise travelers to endemic areas to take precautions, including protecting open wounds and seeking prompt medical attention if unusual symptoms like painful or infected wounds, swelling, or fever occur after returning from affected regions. Early diagnosis and treatment are essential to prevent serious complications.

While the immediate risk to the U.S. population remains low, this case highlights the importance of vigilance and preparedness in addressing emerging infectious threats.