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The US beef market could be affected by the presence of flesh-eating worms in cattle

Experts say that the New World Screwworm is a parasite that has been eating cattle and wild animals alive for years. It is now moving northward from Central America towards Mexico, and it has surpassed biological barriers which had kept this pest in check for decades.

Washington stopped cattle imports in May due to the spread of the insect into Mexico. This was about 700 miles away from the Texas border. The U.S. herd is already at its lowest level in decades, and the closure of the border could increase beef prices to record levels by preventing more calves from entering the U.S. supply.

What is New World Screwworm?

Screwworms, parasitic flies that lay their eggs in the wounds of warm-blooded animals. Usually, wild and livestock animals are the victims. After hatching, screwworm larvae burrow into living flesh with their sharp teeth. They feed, increase the size of the wound, and can eventually kill their host without treatment.

A tiny scratch, a brand that has recently healed, or an ear tag that is healing can become a large wound covered with maggots, which puts the whole herd at risk. Researchers began releasing large numbers of male screwworm flies in the 1960s, which mated with wild female screwsworms and produced infertile eggs.

Why is this important to U.S. customers?

Every year, the U.S. imports more than a million beef cattle from Mexico. The suspension of imports will probably contribute to higher beef prices, as it will tighten the supply after ranchers were forced to reduce their herds due to drought.

Experts said that the U.S. price of beef was likely also boosted by a separate suspension in imports from Mexico due to screwworms, which lasted between November and February. The upward pressure on prices is expected to continue through summer grilling. Experts say that Mexican cattle are typically fed and fattened in the United States for five to six month before slaughter. A reduced slaughter rate could increase beef prices.

Even though the fly is thousands of miles from the border, an outbreak in the U.S. could further restrict the cattle supply as well as put household pets and other livestock at risk. Dr. Timothy Goldsmith is a professor of veterinary medicine at the University of Minnesota. He said that screwworms can feed on humans. Goldsmith explained that homeless people are more susceptible to infestations because they often sleep outdoors and lack access to hygiene and medical products.

What steps are being taken to contain the outbreak?

One factory in Panama that breeds and sterilizes screwworms releases 100 million sterile fly every week. But experts say there are more factories needed to stop the spread of this fly north.

Sonja Swiger is an entomologist from Texas A&M University. She said that screwworms can't fly much more than 12 miles, but when they burrow inside their hosts, they can travel a great distance. In Panama and Mexico the flies are already past the narrowest land stretches, so it is necessary to release a large number of sterile flies to stop the outbreak.

The U.S. Department of Agriculture (USDA) announced on Tuesday that it will invest $21,000,000 to convert a fruit flies factory in Mexico into a facility for the production of sterile screwworms. The agency stated that the border would likely be reopened to cattle imports before the end of this year.

What could be the impact on American cattle ranchers if this happens?

According to the USDA, a screwworm epidemic in Texas would cost $1.8 billion due to livestock deaths, costs of labor and medication. Most cattle ranchers are no longer equipped to diagnose or treat screwworm after decades of eradication. Treatment involves the removal of hundreds of larvae from wounds and thorough disinfection. This is a laborious, expensive and time-consuming process.

This is a pest that we do not want to see again. David Anderson, a livestock economist at Texas A&M University, said that this was a bad situation. I can't even imagine dealing with it. It's gross." Reporting by Heather Schlitz. (Editing by Emily Schmall, David Gregorio and Emily Schmall)

(source: Reuters)