A dangerous parasite, the New World screwworm (NWS), may have reached the United States after over 100 years. The US Department of Agriculture (USDA) has issued warnings following a reported infestation in southern Mexico near the Guatemala border.
The larvae of the NWS fly are flesh-eating maggots. They hatch from eggs laid by flies on fresh wounds of warm-blooded animals, including humans. If untreated, these larvae can infest the bloodstream, causing a condition called myiasis.
New World screwworm Myiasis
New World screwworm (NWS) is a parasitic worm that feeds on live tissue and can cause myiasis. It mainly affects livestock but can sometimes infect humans. NWS flies lay their eggs in open wounds, and the larvae feed on tissue.
NWS infestations are very painful. You may see maggots in or around an open wound, or even in the nose, eyes, or mouth. Wounds may not heal, worsen over time, and have a bad smell.
Secondary infections can cause fever or chills. Other symptoms include bleeding, pain, and the sensation of larvae moving in the wound.
The USDA has suspended Mexican beef imports and urged US farmers to monitor livestock for symptoms, implement de-worming protocols, and use pesticides to eliminate the larvae.
Health officials warn that a widespread outbreak would devastate agriculture, cost billions of dollars, and pose a significant risk to human health.
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