Quick bites from around the food safety arena
A German company has been identified as the maker of infant formula linked to an outbreak of infant botulism in the U.S. Milchwerke Mittelelbe GmbH, also known by its brand name Elb-Milch, manufactures formula for Nara Organics. Three babies under the age of 6 months have contracted infant botulism after consuming Nara Organics Whole Milk Organic Infant Formula. No deaths have been reported.The First Steps Nutrition Trust, a charity based in the United Kingdom, called for better surveillance of food poisoning symptoms in infants and improved public health messaging related to infant formula. This follows the discovery of cereulide in infant formula sold by several companies. The toxin was responsible for more than 140 cases of food poisoning across 10 countries early this year. The European Commission is also considering tighter regulation of baby formula and special infant foods to ensure cereulide is not present.Inorganic arsenic and lead topped the list of foodborne chemicals threatening the world food supply, according to the World Health Organization’s latest foodborne illness estimates. Cardiovascular diseases related to the two chemicals caused almost 90% of foodborne chemical deaths.A new collection of studies published in the July issue of the American Journal of Public Health connect efforts to downplay the addictive-like properties of some ultra-processed foods to Big Tobacco’s long campaign to distract from the dangers of cigarettes. Tobacco-owned food companies produce some of the foods associated with increased likelihood of developing dementia and mild cognitive impairment. Roughly 60 percent of the American diet now consists of ultra-processed foods, according to this research.
Today’s Topic: Screwworm II
For the first time in 50 years, widespread infections by the New World screwworm must be fought on U.S. soil, as its larvae feed on the living tissue of warm-blooded animals in Texas and New Mexico.
The flesh-eating parasitic fly arrived in the United States with the June 3 USDA report confirming the detection of New World screwworm (NWS) in a cow in Zavala County, Texas. Up to a dozen infestations of Texas cattle and one unfortunate dog in New Mexico have since been reported.
What NWS is not is also important. It is not a food safety issue. It is not contagious. It does not spread from animals to people.
With proof that NWS had crossed over from Mexico, several developments were immediately triggered, including:
President Trump named Texas A&M Regent John Bellinger as the new Senior Advisor for New World screwworm preparedness. In this role, Bellinger will integrate into the USDA’s team to help further drive its robust effort to explore all available technologies to combat NWS, according to Secretary of Agriculture Brooke L. Rollins.The Food and Drug Administration announced an Emergency Use Authorization for the drug nitenpyram to treat screwworm infestations in dogs and cats, making it the first generic drug approved for use against screwworm. Canada temporarily banned livestock imports from Texas due to confirmed cases of the flesh-eating screwworm, affecting cattle, horses, bison, and other animals that were in Texas within 21 days of crossing the border. Asked if USDA might reopen the U.S.-Mexican border to imports of Mexican cattle now that the screwworm is on both sides, Secretary Rollins said, “It is not lost on me.” She added, “We will continue to watch the data very, very, very closely.” The U.S. suspended imports of Mexican cattle in May as the parasite neared the American border. Mexico had supplied about 1.2 million head of cattle annually to the United States, primarily feeder cattle destined for U.S. feedlots.
The rapid emergence of at least 12 screwworm infestations also sparked political controversy.
The early termination of USAID funds for a United Nations NWS monitoring program last year was blamed by some for the resurgence. The amount of that foreign aid was likely not significant, in that the USDA’s spending on screwworm eradication has topped $1 billion.
Mobilization to fight NWS is not without critics
With its animal disease-fighting Animal and Plant Health Inspection Service (APHIS), the USDA has mobilized emergency responses, including sterile-fly releases, import suspensions, and construction of domestic sterile fly production facilities
But Texas Agriculture Commissioner Sid Miller contends that the USDA’s response to the screwworm’s arrival in the USA relies too heavily on an “ineffective approach.”
Miller has been Texas Agriculture Commissioner for more than a decade. He is a controversial conservative Republican who fell out of favor with Texas Gov. Greg Abbott and lost his primary this year, making him a lame duck.
Still, Miller’s views about the screwworm are worth considering.
In a statement, Miller called for the USDA to use the Screwworm Adult Suppression System, known as SWASS, a bait-and-insecticide technology designed to reduce adult screwworm fly populations in addition to the ongoing sterile fly releases.
In other words, Miller wants the USDA to pair its sterile fly release program with SWASS rather than relying so much on just one approach.
“You don’t win this battle with one tool,” Miller said. “You kill fertile flies with SWASS while overwhelming the remaining population with sterile flies.”
In his statement, Miller said, “USDA must stop dragging its feet and deploy every available tool before this outbreak spirals further out of control.”
Miller added some controversy by opining that Texas ranchers are unlikely to report screwworms because doing so might result in a quarantine of their property.
He said, “If I get a screwworm on my place, I’m going to treat my animal, and I’m not telling anybody because I don’t want to be quarantined. [Quarantine] means no cattle can move off my place, I can’t sell my cattle, I can’t ship them, I can’t move pastures. Nobody is going to report when they have a screwworm flight, they’re just not. They’ll treat it themselves and hope nobody finds out.”
Agriculture Secretary Brooke Rollins did not appreciate the views of her state counterpart. She called his views a “dangerous suggestion.”
“That is a very unserious comment from perhaps an unserious ag commissioner with just a few months left,” she told a Kerrville, TX press conference held after the screwworm’s U.S. arrival was reported.
USDA has increased surveillance and trapping efforts, established quarantine zones around confirmed detections, and begun releasing sterile flies designed to prevent reproduction.
How we got here
Starting in June 2023, the New World screwworm reappeared in Panama and started spreading across Central America. Before being detected in the U.S. this month, it has been found in Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua and Mexico.
The screwworm is a parasite that infests warm-blooded animals, causing severe damage to the flesh. The larvae, or maggots, burrow deep into the tissue, causing extensive damage and leaving infections and wounds that don’t heal. The larvae can grow to 17 mm with spines that wrap around in a spiral, thus the “screwworm” name.
The spread of NWS (Cochliomyia hominivorax) and its serious threat to both domestic and wild animals, humans, and the environment require strengthening surveillance and diagnostic capacities, ensuring transparent and timely disease reporting via the World Animal Health Information System (WAHIS) and promoting collaboration across food sectors and borders.
No vaccines or biological products are currently available for NWS control, although eradication programs based on the sterile insect technique (SIT) using sterilized male flies have been successful in the past.
The New World screwworm fly and the Old World screwworm [Chrysomya bezziana (Villeneuve)] are both obligate parasites of mammals during their larval stages.
All living warm-blooded animals can be infested by screwworm, but it is most common in mammals, while rare in birds. Many cases of screwworm myiasis (infestation of tissue by fly larvae) have been documented in humans.
A closer look at eradication strategies
The Screwworm Adult Suppression System (SWASS), favored by the Texas Ag Commissioner, was developed by USDA scientists in the 1970s to control adult populations of the New World screwworm.
A rapid-response tool to protect livestock, wildlife, and companion animals from the destructive screwworm, SWASS was first tested and deployed in the 1970s and early 1980s in the United States and Mexico, complementing the Sterile Insect Technique (SIT), in which sterilized male flies are released to disrupt reproduction.
That system proved valuable in reducing dense tropical screwworm populations, making the SIT more effective and contributing to the eradication of screwworms from northern Mexico and the U.S. Southwest by the early 1980s.
Key Advantages of SWASS
Targets adult screwworms, especially females, reducing reproduction rates.Uses species-specific attractants to increase effectiveness.Can be deployed alongside sterile fly releases for integrated pest management.Proven in historical eradication campaigns in the U.S. and Mexico
Advantages of SIT
Environmentally friendly: Reduces reliance on chemical insecticides, minimizing ecological and human health risks Species-specific: Targets only the pest species without affecting beneficial insects Sustainable: Provides long-term population control when combined with monitoring and other management practices Safe: Sterile insects do not produce harmful larvae, posing no risk to wildlife, livestock, or humans
Our take
In June 2023, Panama became the first country to notify the World Organization for Animal Health (OIE) of the New World screwworm resurgence—marking the formal start of the current outbreak wave.
In late 2023, Costa Rica and other Central American countries began reporting cases, and the outbreak was recognized as a regional issue rather than a single-country event.
Through 2024, NWS spread north and west, with detections across all Central American countries and Mexico, where it had previously been controlled. The screwworm attacked livestock, wildlife, and some humans in those countries, according to OIE outbreak summaries.
In August 2025, OIE reported more than 20,000 new outbreaks, and U.S. state health departments began issuing health advisories warning travelers and clinicians about NWS south of the border.
The screwworm then arrived in the U.S. in June 2026, three years after the resurgence began. USDA’s readiness measures all failed to prevent the screwworm’s entry.
That does not mean the USDA won’t be effective in screwworm eradication. It is unclear why decision-makers are not using the Screwworm Adult Suppression System (SWASS), which, like the SIT, is a historically successful USDA program.
Sid Miller can be a pain in the rump, but ignoring his support for SWASS could prevent an early success.
By the numbers
1966 – The year screwworm was eradicated from the U.S., according to the USDA’s Animal and Plant Health Inspection Service. A small outbreak in the Florida Keys was eliminated in 2017.
200-300 – The number of eggs one NWS female fly can lay at one time. Each female fly may lay up to 3,000 eggs in its lifetime. However, the release of sterile male flies can drastically reduce that number until the flies die without reproducing.
16,725 – The number of screwworm outbreaks reported in 2024 and early 2025, as documented in OIE’s international report on prevalent animal health issues. Nineteen countries reported outbreaks, including 15 exceptional epidemiological events. Nicaragua accounted for over 60 percent of the reported outbreaks. Other affected countries included Belize, Costa Rica, El Salvador, Guatemala, and Honduras.
830 – The number of human cases of NWS infection reported as of the fall of 2025. According to Science News, a Maryland resident became the first recorded infection in the current outbreak after encountering NWS while traveling in El Salvador in 2024.
109,000,000 – The amount, in U.S. dollars, spent in response to the 2023 NWS detection in Panama.
165,000,000 – The amount, in U.S. dollars, spent on control efforts in Mexico and Central America in 2024.
21,000,000 – The amount, in U.S. dollars, spent on the 2025 conversion of a fruitfly facility in Metapa, Mexico, into a sterile-fly rearing operation.
750,000,000 – The amount, in U.S. dollars, of a major federal commitment made in 2025 to build a domestic sterile fly production facility in southern Texas, capable of producing 300 million sterile flies per week. This is the largest single investment in NWS eradication to date.
What it means
USDA and Texas are taking action to contain and eradicate NWS from the United States, following the strategies and actions outlined in the NWS Response Playbook. These include:
Forming a unified Incident Command Team with the Texas Animal Health Commission and deploying response personnel to the area;Establishing a 20 km infested zone around the detection and implementing quarantines, movement controls, and surveillance in this area;Expediting targeted release of sterile NWS flies by immediately deploying ground release chambers in the area, in addition to the 4 million sterile flies per week already being released aerially; Increasing trapping of NWS flies along the border and just outside of the dispersal area;Implementing NWS surveillance and management strategies in wildlife; andConducting targeted outreach in the local area.
Among the resources USDA brings to the party are the National Veterinary Services Laboratories (NVSL), which has labs in two locations: Ames, Iowa, and the Foreign Animal Disease Diagnostic Laboratory (FADDL) at Plum Island, NY.
Diagnostic test services available at those facilities range from a single laboratory test to comprehensive laboratory services covering many pathogens for a suspected disease outbreak.
The new National Bio and Agro-Defense Facility (NBAF) in Manhattan took over operations at Plum Island in 2023 and is part of the Biosafety Level 4 Zoonotic Laboratory Network. The primary research tenants of the facility are the USDA’s Agriculture Research Service and the USDA’s Animal and Plant Health Inspection Service veterinary unit.
NVSL personnel from Ames have reportedly been sent to Texas with the NWS arrival. Further reports on the spread of NWS will soon reveal whether this full court press is getting results.
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