New World screwworm (NWS) myiasis was found in a patient who returned to the US from El Salvador, the Department of Health and Human Services said on Monday. The case was confirmed on 4 August.

NWS myiasis is a parasitic infestation of fly larvae, or maggots, caused by parasitic flies.

The pest primarily affects livestock, and authorities have said the risk to US public health was currently "very low".

The Centers for Disease Control and Prevention (CDC) worked with Maryland's health department to investigate the case.

HHS spokesperson Andrew Nixon said it is the first human case of travel-associated NWS myiasis from an outbreak-affected country identified in the US.