The United States has confirmed its first case of human infection with carnivorous flies

The first case of human infection with "New Continent meat fly" has emerged in Maryland, the United States. The patient entered the country from Guatemala and is currently receiving treatment there. This is the first time that the United States has reported human cases since the parasitic epidemic spread northward from Central America and southern Mexico last year.

Reuters reported that the New World Screwworm feeds on live warm-blooded animals as its hosts. Female flies lay their eggs in wounds, and the hatched larvae will burrowing into the muscles to consume tissues. If not removed in time, it can eventually cause the death of the host.

Another source disclosed that on August 20, the Beef Alliance sent an email to industry insiders, stating that the US Centers for Disease Control and Prevention (CDC) had confirmed this case. Maryland state government officials also confirmed the incident.

A week before the announcement, US Agriculture Secretary Rollins announced in Texas that a fly-killing plant would be built to deal with the threat of the epidemic.

What is a carnivorous fly?

Carnivorous flies are parasitic flies. Female flies lay their eggs on wounds of warm-blooded animals. After hatching, the larvae will use their sharp mouthparts to burp into the muscles of living animals. If left untreated, it can cause the death of the host. The carnivorous fly feeds in a way that resembles a screw screwed into wood, hence its name.

Carnivorous flies pose a significant threat to cattle and wild animals. Although human infections are rare, they can be fatal once they occur. The treatment process is arduous, requiring the removal of hundreds of larvae and thorough disinfection of the wound. However, if dealt with early, they usually survive.

Industrial impact and control measures

As the authorities have not disclosed more case information, it may thus impact the beef and live cattle futures markets. The size of cattle herds in the United States has dropped to the lowest level in 70 years, and prices have reached record highs. Although Rollins has repeatedly promised to prevent carnivorous flies from entering the country, the prevention and control measures have been criticized by some farmers for being too slow.

At present, the United States has installed fly traps at its borders and dispatched mounted police for patrols. In June this year, Rollins announced that it would build a fly control plant at Moore Air Force Base in Edingburg, Texas, which is expected to be operational in two or three years. Mexico has also launched a similar project worth 51 million US dollars in the south.

At present, only one fly control plant in Panama City is in operation worldwide, with a weekly output of approximately 100 million sterile male flies. However, the United States Department of Agriculture estimates that to effectively control the pest population, 500 million flies need to be released each week.

Since 2023, carnivorous flies have been spreading northward, with Cuba, Haiti and the Dominican Republic remaining epidemic areas. In July this year, the state of Veracruz in Mexico (about 600 kilometers from the US-Mexico border) reported new cases, and the United States immediately closed livestock trade at the southern port. The United States usually imports over a million cattle from Mexico every year.

The US Department of Agriculture estimates that if the epidemic gets out of control, Texas alone could cause about 1.8 billion US dollars in losses, including livestock deaths and prevention and control expenses.