FDA warns Neogen after HYCOAT contamination killed horses

The FDA has escalated its response to the HYCOAT contamination case, issuing warning letters to Neogen Corporation and Sciarra Aeromed after an investigation tied the veterinary product to serious fungal infections in more than 95 horses and at least 20 euthanizations. In its September 29, 2026 public update, the agency called it the largest number of horse deaths ever associated with a quality defect in an FDA-regulated veterinary medical product, and the most deaths in any animal species linked to microbiological contamination of an FDA-regulated product labeled as sterile. (fda.gov)

The case traces back to late 2025, when FDA began receiving reports from veterinarians who had used Neogen Vet HYCOAT as an injection, even though the product was labeled as a sterile topical wound management solution for surgical wounds, burns, ulcers, and related uses. Neogen then announced a voluntary nationwide recall on January 28, 2026, covering all unexpired lots for use in dogs, cats, and horses, after adverse-event reports in horses following intra-articular administration. The company said at the time that it had not received reports of adverse events when the product was used according to label directions, but the recall still extended to all unexpired lots out of caution. (fda.gov)

FDA’s warning letter to Neogen lays out the specifics behind the enforcement action. The agency said it reviewed epidemiological and clinical evidence tied to more than 95 individual cases, tested HYCOAT lot 5A001, and identified five viable fungal contaminants: Purpureocillium lilacinum, Paraisaria heteropoda, Gongronella lacrispora, Purpureocillium sodanum, and Isaria takamizusanensis. According to FDA, injecting a contaminated product into a joint can trigger severe inflammation, infection, painful lameness, tissue destruction, and, in some cases, euthanasia when treatment fails. (fda.gov)

The agency also said the problems went beyond a single contaminated lot. In the warning letter, FDA said HYCOAT was manufactured under insanitary conditions at the contract facility, citing inadequate cleaning, no use of a sporicidal agent, inadequate air-quality and environmental monitoring, no personnel sampling for viable microorganisms, and no smoke studies to demonstrate airflow in the ISO 5 area. FDA concluded that the product was adulterated and misbranded, and said Neogen, as distributor, remained responsible for ensuring the product was not adulterated or misbranded before interstate distribution. (fda.gov)

Public expert reaction has so far been limited, but the equine industry press has amplified FDA’s framing of the case as unprecedented in scale. The Horse republished the FDA announcement, underscoring the euthanasia toll and the contamination findings, while AAEP’s broader guidance for horse health and medication decisions has long urged use of legal, FDA-approved products when available, a principle that lands differently in the wake of a failure involving a product marketed as sterile and widely used in practice. That doesn’t amount to a direct AAEP statement on HYCOAT, but it does reflect the profession’s longstanding concern about product quality, sourcing, and patient safety. (thehorse.com)

Why it matters: For veterinary professionals, especially equine surgeons and sports medicine clinicians, this case is bigger than one recall. It highlights how packaging, real-world use patterns, and assumptions around sterility can combine into major clinical risk. FDA noted that HYCOAT was packaged in a vial style commonly used for sterile injectables, and said off-label joint injection represented a common real-world use. That matters for hospital purchasing, informed consent, pharmacy oversight, inventory controls, and post-procedure surveillance. Practices may want to revisit how they vet wound-care and biologic-style products, how quickly they quarantine suspect lots, and whether teams are consistently reporting adverse events to FDA’s Center for Veterinary Medicine. (fda.gov)

The case could also have regulatory ripple effects. FDA’s language suggests the agency is willing to look closely at the gap between labeled indication and foreseeable clinical use, especially when a product is presented as sterile and packaged in a way that may encourage injection. Even if the most severe injuries were tied to off-label use, FDA made clear that contamination also posed risk in labeled wound applications because the product could contact internal tissues or systemic circulation. That may influence how manufacturers draft labeling, how distributors oversee contract manufacturers, and how clinics assess products that sit near the line between wound care, device use, and injectable-style handling. (fda.gov)

What to watch: The next milestones are the companies’ responses to the September 23, 2026 warning letters, any follow-on FDA enforcement, and whether the tally of affected horses rises as more final case outcomes are reported. Because FDA said many injured horses’ outcomes are still unknown, the current count may not be the last word. (fda.gov)