Here’s what to know about the flesh-eating New World screwworm

Data Researcher/Curator

WASHINGTON —

The U.S. Department of Agriculture on Wednesday confirmed the presence of the New World screwworm in Texas. The agency said larvae were found in the umbilical area of a 3-week-old calf.

The Get the Facts Data Team looked at other historical cases of the New World screwworm in the U.S. and what its return could mean for consumers and livestock producers.

What is the New World screwworm?

The flesh-eating parasitic fly feeds on warm-blooded animals and, in rare cases, people. It can cause serious damage to livestock and lead to economic losses.

The screwworm lays its eggs into an open wound, and once the eggs hatch, the larvae burrow into living flesh and feed on tissue. It can be deadly to livestock if left untreated.

The screwworm is typically found in South America and parts of the Caribbean, according to the Centers for Disease Control and Prevention.

Have there been other cases?

The USDA first began collecting data on the screwworm in 1962, recording about 51,600 cases. Years earlier, in 1957, the U.S. started an eradication program to eliminate the flies.

While the USDA said it eradicated the screwworm in 1966, there have been several cases since. The 1972 outbreak was the worst since eradication, with California, Arizona, New Mexico, Texas, Oklahoma and Arkansas reporting screwworm-infected livestock. Texas alone confirmed 90,000 cases.

The most recent outbreak was in the Florida Keys in September 2016, mostly among wild deer, and was contained by early 2017.

The last reported case prior to this was last year, when a Maryland resident was diagnosed after traveling to El Salvador.

What is the USDA doing?

A screwworm was detected 50 miles from the U.S. border last week, according to USDA data.

The department said it was taking immediate action to eradicate the parasitic fly by establishing a 12-mile “infested zone,” implementing a quarantine and increasing traps for the fly along the border.

There have been at least 26,200 identified cases across Mexico, with about 2,700 remaining active, according to the USDA. Last year, the USDA shut down southern border ports to livestock trade to help prevent the spread of the fly.

While the flies pose no threat to food safety, an outbreak could further strain the already low beef cattle inventory, posing a threat to farmers and consumers.