New World screwworm case diagnosed in U.S.

A recent case of New World screwworm has been reported in a Maryland resident who traveled to El Salvador. This marks the first documented case in the United States linked to travel to a country with an ongoing outbreak. The Centers for Disease Control and Prevention confirmed the diagnosis on August 4, with federal health officials acknowledging the infection in a statement on Monday.

Fortunately, the individual has fully recovered, and there have been no instances of transmission to other individuals or animals, according to Maryland health officials. New World screwworm, a type of fly that lays its eggs in open wounds and body openings, is typically found in South America and the Caribbean.

Although rare in humans, New World screwworm has been a significant concern for ranchers due to infestations in cattle moving northward through Central America and Mexico. The CDC is collaborating with the U.S. Agriculture Department to prevent further spread of the parasite.

Historically, New World screwworm was a recurring issue for the American cattle industry until the 1960s and 1970s when it was largely eradicated in the United States, with Florida and Texas being known as hot spots.

While this may not be the first instance of an American being diagnosed with New World screwworm, it is the first case in a U.S. resident in quite some time. Max Scott, a researcher from North Carolina State University, suggests that given the history of the parasite, this case may not be the only one to occur in the country.

New World screwworm, scientifically known as a blue-green blowfly, gained notoriety in the 19th century for infestations at the Devil’s Island penal colony. Female flies lay eggs in wounds or body openings, leading to larvae that consume flesh. The maggots, resembling screws, can grow up to two-thirds of an inch and embed themselves in the flesh.

Symptoms of New World screwworm in humans include painful wounds that do not heal, the presence of maggots around sores, and a foul odor from affected areas. While the larvae do not spread from person to person, those with open wounds and exposure to livestock in infested areas are at greater risk.

Treatment for New World screwworm involves the removal of larvae, sometimes through surgical procedures. It is crucial not to attempt removing the maggots independently, as advised by the CDC.

There is a possibility of more cases in the U.S., as efforts to control the parasite have faced challenges in recent years. Genetic techniques are being developed to combat the spread of New World screwworm, with the U.S. government intensifying its initiatives to manage the parasites. However, the potential for reemergence remains a concern.

Should the parasite resurface in the United States, the Texas-Mexico border area is likely to be the initial site of occurrence. Scientists and officials continue to monitor and address the threat of New World screwworm to prevent further outbreaks.