U.S. Screwworm Update: Cases Rise to 32 Since June 3 as Reports Increase Across Texas

New World screwworm is no longer a distant livestock-health concern that we are protecting against; it is firmly here in the United States.

USDA has now documented 32 cases in the U.S. since June 3, with nearly all of them reported in Texas. Most of the cases have affected cattle, though infections have also been reported in sheep, goats, and dogs. Screwworm is not a routine parasite problem; it is a flesh-eating pest that can severely injure or kill livestock if it’s not caught and treated quickly.

What makes screwworm different from other parasites is how it attacks the animal

Adult flies are attracted to open wounds, even small ones like branding sites, castration cuts, tick bites, or navel areas on newborn calves. The female fly lays eggs in the wound, and within hours, those eggs hatch into larvae. Unlike typical maggots that feed on dead tissue, screwworm larvae feed on living flesh. They burrow deeper into the wound in a screw-like pattern, which is where the name comes from.

As the larvae feed, the wound becomes larger, wetter, and more painful. Ranchers may notice animals acting restless, isolating themselves, or showing signs of discomfort like tail switching, kicking at their sides, or refusing to eat. A strong, foul odor is often one of the first noticeable signs. In more advanced cases, the wound can appear deep and raw, with visible larvae moving inside it.

From an animal sciences standpoint, the damage goes beyond the surface.

The feeding activity causes tissue destruction, inflammation, and secondary bacterial infections. As the wound expands, it can lead to significant blood loss, toxemia, and systemic infection. In severe cases, especially in young, weak, or untreated animals, screwworm infestations can be fatal. Even when animals survive, weight loss, reduced performance, and long-term tissue damage can impact productivity.

The United States has faced this threat before, and the last major outbreak offers important context

Screwworm was once widespread across the southern U.S., costing the livestock industry millions of dollars each year. A coordinated eradication effort began in the 1950s using the sterile insect technique, where millions of sterilized male flies were released to disrupt reproduction. By the 1980s, the pest had been successfully eliminated from the U.S., with the exception of occasional reintroductions. One of the most notable recent incidents occurred in 2016 in the Florida Keys, where screwworm affected endangered Key deer and required an aggressive response to contain and eliminate the outbreak. That history shows both how serious the threat can become and how critical rapid response is to stopping the spread.

For ranchers, the timing is especially concerning.

The cattle industry is already dealing with tight supplies, high replacement costs, labor challenges, animal movement concerns, and elevated beef prices. A parasite outbreak adds another layer of risk. It requires more monitoring, faster treatment decisions, and stronger communication between ranchers, veterinarians, state animal-health officials, and the USDA.

This is also a labor story

During earlier eradication efforts, ranches often had more consistent labor available to check livestock closely. Today, many operations are covering more ground with fewer people. That makes surveillance harder, especially in rough country or large pastures where wounds, infestations, or wildlife exposure may not be spotted immediately.

The sterile-fly response is important, but capacity is part of the concern. The basic strategy is to release sterile flies so the wild population cannot reproduce effectively. That approach helped eliminate screwworm from the U.S. decades ago, but a modern outbreak raises questions about whether current production and response systems can move fast enough.

The takeaway is simple: livestock health is not separate from the Western economy. It is the foundation of it.

Record Beef Prices Are Turning the Fourth of July Into a Ranching Story

This Fourth of July, the price of a hamburger is telling a much bigger story about the cattle industry.

Reuters reports that the average retail price for lean and extra-lean ground beef hit a record $8.62 per pound in May, up more than 12% from a year earlier. Wells Fargo also estimated that a barbeque for 10 people will cost $161 this year, up 2.4% from last year, with hamburger beef rising especially sharply.

For consumers, that shows up as a sticker shock.

For ranchers, it points to a deeper supply problem.

The U.S. cattle herd is still tight after years of drought, wildfire pressure, high feed costs, and difficult rebuilding conditions. When ranchers cull cows because pasture and hay are limited, the effects do not reverse quickly. Even when producers decide to retain heifers and rebuild, it takes years before those animals become part of the beef supply.

That timeline matters. Beef is not a product that can be increased overnight.

The story is also complicated by New World screwworm concerns and blocked Mexican cattle imports. When cross-border cattle movement is limited, the U.S. loses access to a supply channel that normally helps feedyards and processors. That adds pressure to an already tight domestic market.

Politically, this creates a difficult conversation. Consumers want lower beef prices. Ranchers want strong cattle prices after years of hard conditions. Policymakers may look at imports or meatpacker investigations. Producers worry that those solutions may not address the real structural issue: there are fewer cattle, and rebuilding takes time.

Elevated food prices are not just “greed” or “inflation” in a generic sense. They are tied to weather, biology, trade, disease control, land conditions, feed costs, and years of market pressure.

The Fourth of July grill is not separate from the ranch economy.

This year, it may be one of the clearest places consumers can feel the pressure the American rancher faces.