What is the New World screwworm? The flesh-eating fly making a comeback

A The parasitic -eaten flesh fly invades the north and Central America. The consequences could be serious for the cattle industry, but this parasite is not difficult – it will infest a wide range of hosts, including humans and their pets.

THE “New Worldworm” (Cochliomyia hominivorax) was previously eradicated from these regions. Why does it come back and what can be done on this subject?

Flies fulfill important ecological functions, such as pollination and decomposition of non -lively organic matter. Some, however, have evolved to feed on the living.

The female screw fly fly is attracted by the smell of any injury to place it eggs. The larvae (asticots) then nourish themselves aggressively living tissue causing immeasurable suffering to their unlucky host, including death if it is not treated.

Texas livestock producers estimated in the 1960s that they treated approximately 1 million cases per year.

Between the 1960s and 1990s, scientists and governments worked together to use fly biology Mexico Using the technique of sterile insects (SIT).

A woman with screws is not accompanied by once before laying her eggs, while the males are promised. During the eradication process, billions of sterile males were released from planes, preventing any woman who relied with them from producing viable eggs.

In combination with the chemical treatment of cattle and fresh times, the populations of the screw worm were extinguished in the United States in 1982. The eradication campaign would have been costly at $ 750 million (555 million pounds sterling), allowing the production of cattle to increase considerably.

For decades, an installation in Panama has regularly released millions of sterile flies to act as a barrier to the new screw to screw to the north of the south.

However, since 2022 – and after decades of eradication – the lock of the new world has once again spread to the north through several countries of Central America. The cases exploded in Panama in 2023 and the fly arrived in Mexico in November 2024.

Scientists have suggested several hypotheses for this spread, including flies with livestock movements, higher temperatures improving the development and survival of flies, and the possibility that women adapt their sexual behavior to avoid sterile men.

About 17 million cattle are now threatened in Central America, but it can be worse to come. Mexico has twice as much cattle, and spread to the United States continues, where around 14 million cattle would be in danger in Texas and Florida.

Humans are not spared, with at least eight cases of flies infesting people in Mexico since April.

Prohibition of living animals

The United States has responded by temporarily restoring imports from living animals from Mexico. The governments of the United States, the countries of Central America and Mexico also work together to increase surveillance and strive to eradicate the lock of the new world by intensifying versions of sterile insects.

Sterile male on (juvenile) pupes are currently produced and safely sterilized by irradiation at a rate of more than 100 million per week in an installation in Panama. This is jointly funded by the US Department of Agriculture (USDA) and the Panama Ministry of Agriculture Development. However, a successful eradication campaign may require this number of sterile flies several times.

For example, the production of sterile flies for outings in Mexico in the 80s would have exceeded 500 million flies per week. To fight against this shortfall, the USDA concentrates outings in critical areas in Mexico and already invests $ 21 million to equip a production of fruit flies in Metapa, Mexico, to also produce 60 to 100 million sterile screws per week.

The production, sterilization and liberation of the fly is a long process, and a reduction in populations from worms to wild screws would not be immediate. History has shown us that the control integrated into anti-parasitic veterinary drugs is essential to repel flies and treat infestations as you go.

Surveillance with qualified personnel is also essential, but it is a great challenge due to an entire generation of veterinarians, technicians and farmers who have no living memory of infestations from worms to the screw.

Finally, global warming means that we cannot be blessed with fresh time which has facilitated the previous eradication, and additional work is necessary to determine how this will have an impact on current eradication plans.

The Hannah Rose plywood is a Principal speaker at the Infection Institute, Veterinary and Ecological Sciences, University of Liverpool. Livio Martins Costa Junior is a teacher of parasitology. This article is republished from the conversation under a Creative Commons license. Read it original article