The U.S. has reported its first human case of the New World screwworm, a flesh-eating parasite. The case was confirmed on August 4 in a patient who had recently traveled to El Salvador, according to the Department of Health and Human Services (HHS). An HHS spokesperson stated that the risk to public health in the U.S. remains very low.

The New World screwworm is a type of parasitic fly whose larvae feed on the living tissue of warm-blooded animals, including livestock and, in rare instances, humans. Andrew Nixon, an HHS spokesman, noted, "This is the first human case of travel-associated New World screwworm myiasis from an outbreak-affected country identified in the United States."

The parasite has been spreading across Central America since early 2023, with significant infestations reported in countries such as Belize, Costa Rica, Guatemala, and Panama. The U.S. Department of Agriculture (USDA) has expressed concern over the parasite's potential impact on the agricultural sector, particularly livestock. The USDA stated that the New World screwworm poses a threat not only to ranchers but also to the food supply and national security.

Historically, the New World screwworm was eradicated in the U.S. during the 1960s and 1970s through a method involving the release of sterilized male flies to mate with females, thereby reducing the population. However, recent outbreaks in Central America have raised alarms. The USDA has announced plans to build a sterile fly production facility in Edinburg, Texas, which could produce up to 300 million sterile flies per week. This facility will work in conjunction with existing operations in Panama and Mexico.

In response to the growing threat, the USDA has also implemented measures such as hiring mounted patrol officers for wildlife surveillance and training dogs to detect screwworm infestations at ports of entry. Earlier this year, the USDA temporarily banned imports of live cattle, horses, and bison from Mexico due to the parasite's spread.

The Centers for Disease Control and Prevention (CDC) has advised that individuals who travel to areas affected by the New World screwworm, spend time around livestock, or have open wounds are at a higher risk of infestation. The CDC emphasized that while the parasite can be harmful, it is not contagious.

Experts warn that if left untreated, screwworm infestations can lead to severe health complications, including sepsis. The larvae can cause significant damage to the host's tissue, and in some cases, can be fatal. The USDA is investing $100 million in technologies to combat the screwworm threat, including traps and therapeutic measures.

As the situation develops, federal authorities are taking proactive steps to prevent the parasite from establishing a foothold in the U.S. The introduction of the New World screwworm could have dire consequences for the cattle industry, which is already facing challenges in the current market.