First US Human Case of Flesh-Eating Screwworm Confirmed

A concerning health development has emerged in the United States with the confirmation of the first human case of the New World screwworm. This painful parasitic infection, typically affecting livestock, has now been identified in a Maryland resident who recently returned from El Salvador.

Understanding the New World Screwworm

The New World screwworm fly lays its eggs on warm-bodied animals, and its larvae burrow into flesh, essentially feeding from the inside out. While humans are rarely affected, infections can occur, especially if larvae enter open wounds or exposed areas. The Centers for Disease Control and Prevention (CDC) confirmed the infection on August 4th. Health officials have reassured the public that the risk to public health in the U.S. is considered very low.

This marks the first identified travel-associated case of New World screwworm myiasis (infestation by fly larvae) in the United States originating from an outbreak-affected country. The parasite’s spread has been noted moving northward from South America in recent years, making this confirmation a point of vigilance for health authorities.

Symptoms, Treatment, and Prevention Efforts

The CDC describes the infestation as “very painful,” often with visible or palpable maggots near the infection site. Larvae can infest skin wounds, as well as the nose, eyes, or mouth. Prompt medical intervention, sometimes involving surgery, is required for larvae removal. While treatable and rarely fatal if addressed quickly, untreated cases can lead to serious health risks.

In response to the growing threat, the U.S. Department of Agriculture (USDA) is implementing preventative measures. Secretary of Agriculture Brooke L. Rollins announced plans to release sterile male screwworms into affected areas. This method aims to significantly reduce the screwworm population, as females mate only once.

A Reminder of Zoonotic Risks

This case serves as a crucial reminder that parasites primarily impacting livestock can occasionally infect humans. Early detection, monitoring, and swift medical care are vital components in managing such infections and safeguarding public health. While this is the first confirmed human case linked to travel in the U.S., health officials are actively monitoring the situation.