Understanding New World Screwworm: The First Human Case in the US

The United States has reported its first human instance of an infection by the flesh-eating New World screwworm. The Department of Health and Human Services made this announcement recently.

Originating from travel to El Salvador, a resident of Maryland is the first individual in the country confirmed to have contracted this parasite, as reported to ABC News by an HHS representative.

The Spread of a Flesh-eating Parasite

An outbreak has been noted in livestock across Mexico and Central America, raising concerns about the reach of this parasite beyond its typical territories.

Identifying New World Screwworm

A known parasitic fly, the New World screwworm, thrives on live flesh, causing myiasis when its larvae infest wounds. Various animals, including domestic pets, farm animals, and wildlife, can fall prey, with humans rarely affected.

According to Lori Ferrins from Northeastern University, these parasites burrow into open wounds. Upon landing, the screwworm females lay extensive batches of eggs, leading to deeper maggot intrusions as they hatch.

These infections, seldom seen in the United States, are primarily found in Central and South America and the Caribbean. Symptoms can range from non-healing skin sores, pain, bleeding, and foul odors to the visible presence of maggots.

Medical Response to Screwworm Infestation

Although no preventive vaccine exists, treatment is available. Early healthcare intervention is vital upon suspecting infection, as advised by the CDC. Professional removal of larvae, potentially requiring surgical methods, is the recommended approach.

Preventive Measures

Travelers to regions with known infestations should employ protective practices like wearing protective clothing and using effective insect repellents.

Ongoing efforts in the United States aim to prevent the parasite's spread. Strategies include sterilizing male flies to interrupt the reproductive cycle, a method successfully used in the 1960s.

Current Risk Assessment in the US

While the US has largely kept screwworm at bay since 1966, sporadic events, such as a localized animal outbreak in 2017, remind of its potential threat. Nonetheless, human infections remain exceedingly rare.

The US Department of Agriculture acknowledges the risk to livestock and subsequently to national food supplies and security. Still, experts urge caution without alarm as local cases are unsubstantiated.