A flesh-eating screwworm case has been confirmed in Maryland after a patient visited El Salvador. This is the first case of travel-associated New World screwworm myiasis in the U.S. Health officials maintain the risk to the American population is still very low.
However, this finding underscores the alarming risk still presented by the parasite.
What is a Flesh-Eating Screwworm?
The New World screwworm is a parasitic fly. Its larvae feed on the living tissue of animals and, in rare occasions, humans. Female flies lay eggs in open sores. The larvae and eggs cause severe tissue damage as they burrow deeper.
If untreated, myiasis infestation can cause disfigurement, secondary infections, and, in some instances, death.
History of Screwworms in the U.S.
Screwworms of the New World variety were eradicated in the US because of a successful sterilization program that released billions of sterile flies to reduce reproduction. The Florida Keys were the last area in the US to have an outbreak in 2017, where it was swiftly contained.
However, the recent discovery of a flesh-eating screwworm case in Maryland highlights the dangers posed by international travel and livestock imports.
Current Flesh-eating Screwworm Case in Maryland
Health officials confirmed the case after performing a lab analysis on the larvae sent from the patient’s wound. The CDC along with the Maryland Department of Health verified the infestation cases with expert reviews.
Although the patient traveled to El Salvador, some reports suggested the infection might have originated in Guatemala. Regardless of the source, the CDC emphasizes that human cases are very rare but the cases can be travel exposed from outside the US.
Flesh-Eating Screwworm Case: Why It Matters
The impacts of a flesh-eating screwworm case affect humans and animals greatly. The USDA has stated that the reestablishment of screwworms in Texas could cause a $1.8 billion loss to the economy from the cattle industry.
The larvae of these screwworms inflict severe and painful wounds in cattle which results in suffering, loss of productivity, and expensive eradication programs.
Human Symptoms and Risks
The CDC has stated that people with open wounds and are located in areas where screwworms are prevalent, will be most at risk. The list of symptoms of infestation includes:
- Flesh-Eating Screwworm Case: Intense pain where the condition is present.
- Skin lesions that do not heal and deteriorate progressively.
- Bleeding and signs of tissue decay.
- The repulsive feeling of larvae wriggling within the skin, nose, mouth, and even the eyes.
South American as well as Caribbean and Central American explorers should be more careful, especially with abnormal or complicated infection of the wounds.
Outbreak Prevention Strategies in the U.S.
With regards to livestock alongside public health, U.S. authorities have tightened strategies around the southern border with the following changes:
- Place a ban on the import of some livestock from regions afflicted with the outbreak.
- Expand the sterile fly release program to southern Texas and Mexico.
- Deploy synthetic attractants like “Swormlure” to kill and capture adult flies.
- Create additional livestock and vaccine treatments to control the disease.
Texas, which has the largest cattle ranching industry in the entire country, has been particularly proactive. Advanced fly traps, protective feed additives and collaboration with the federal government have also been reported to be in the works out of the Texas Department of Agriculture.
Can Screwworms Infest US Wildlife?
Researchers have recently discovered that screwworms are now infesting new species like mountain tapeirs in South America which are more concerning as they seem to have a greater adaptability to change.
Wildlife such as deer and livestock would suffer devastating infestations if the parasite infests the US again.
Conclusion: Staying Alert After The Flesh Eating Screwworm Case
The flesh-eating screwworm case that was picked up in Maryland remains contained and poses no immediate threat to the wider population and serves as a reminder for the dangers that border cross livestock movement poses.
Strong border biosecurity helps to contain the parasite. For now, the threat to public health is minimal, and proactive action is crucial to avoiding another outbreak. Closer to the borders, surveillance and health monitoring needs to be heightened to prevent the invasive screwworm.
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