An American from Maryland who stayed in El Salvador unknowingly brought back an unwanted guest: the larva of a screwworm. The larvae of this fly need a host to complete their evolution, a host on which they feed. The infection was detected in early August after confirmation from the Center for Disease Control and Prevention (CDC), reports online media Ars Technica.
Contrary to what some headlines claim, this is not the “first case” on American soil. Similar travel-related infections have been seen before, the last one being last year. Experts point out that this parasite, endemic in Latin America and the Caribbean, can sometimes infect travelers. However, the danger to public health remains considered “low” by Andrew Nixon, spokesperson for the US Department of Health and Human Services.
Although this new case does not constitute a direct threat, the situation remains worrying. Once eradicated from the United States in the 1950s thanks to a massive campaign (including the release of millions of sterile flies), the flesh-munching animal has resurfaced in Central America. The measures taken in particular in Panama have not made it possible to block indefinitely what is also called the “flesh fly” which is now dangerously close to the Texan border.
A formidable parasite for livestock
The larva of Cochliomyia hominivorax attacks all warm-blooded animals. They sink into the wounds or orifices of their victim, causing painful lesions, often fatal for wildlife and livestock. According to the US Department of Agriculture, an invasion in Texas could cause up to $1.8 billion (around 1.5 billion euros) in losses in the livestock sector.
In humans, the infection is rarely fatal, but the symptoms are extremely violent: pain, secondary infections and surgical extraction of each larva are on the agenda. The CDC cites the case of a patient living in Florida and returning from the Dominican Republic. He required emergency surgery after 150 larvae were detected in his nasal cavity. Other cases have been recorded in recent years among travelers from Argentina or Brazil.
Faced with this threat at the country’s gates, the American federal authorities are considering building a new facility intended to produce sterile flies in order to stem a possible invasion. Even if the human case detected in Maryland only presents a health risk, the growing proximity of screwworms to the American border is worrying.
