FDA clears Zoetis screwworm treatment for dogs and puppies

The US Food and Drug Administration has granted an emergency use authorisation (EUA) for a New World Screwworm treatment aimed at dogs and puppies, naming Zoetis Inc. (NYSE: ZTS) as the sponsor of the drug in question, according to the FDA’s press announcement dated 13 August 2026. The authorised product is Simparica Trio, a chewable combining sarolaner, moxidectin and pyrantel, cleared for use against New World screwworm myiasis – a parasitic fly infestation that has been working its way north through the Americas. Reuters independently confirmed the authorisation the same day, reporting it under the headline “Zoetis gets US FDA emergency use nod for treatment for screwworm in dogs.”

The fifth authorisation in a widening response

This is not the FDA’s first move against the outbreak, and it is worth reading Zoetis’s news in that context rather than in isolation. Elanco’s Credelio, a rival flea-and-tick chewable, was billed by its own maker as the first-ever FDA emergency authorisation against New World screwworm in dogs – issued, notably, before the fly had even been detected on US soil, according to an Elanco release carried by SeekingAlpha. Since then the agency has kept adding to the list: NexGard received an authorisation on 18 February 2026, a generic nitenpyram tablet followed on 11 June, and a wound spray for livestock, CLiK Extra, was cleared on 7 August – all tracked on the FDA’s own New World screwworm animal-drug page. Zoetis’s Simparica Trio nod is the latest entry in what now looks like a sustained, multi-company regulatory campaign rather than a one-off event.

A public health emergency that is also a revenue line

For Zoetis, the outbreak has already shown up in the numbers before this latest authorisation. On its second-quarter 2026 earnings call, the company said US livestock revenue rose 23% on elevated demand for Dectomax and other injectable parasiticides tied directly to the screwworm outbreak, even as it trimmed full-year guidance elsewhere on softness in its dermatology business, according to a transcript carried by The Globe and Mail. Simparica Trio itself is no minor product line – it generated $350 million in second-quarter 2026 revenue, down 1% year-on-year, before this week’s authorisation potentially widens its use case into New World screwworm treatment.

That sits against a company generating meaningful scale: Zoetis reported first-quarter 2026 revenue of $2,262 million and diluted earnings per share of $1.42, according to its 10-Q filed with the SEC on 7 May 2026. For the full 2025 financial year, the company posted revenue of $9,467 million and net income of $2,673 million, per its annual report filed with the SEC in February 2026 – up from $2,486 million in net income the year before. An emergency authorisation does not, by itself, move a company of that size. But layered onto an outbreak that is already lifting livestock-drug sales, it extends Zoetis’s exposure to the crisis across both the pet and livestock sides of its business.

What the positioning data shows

There is little sign that traders were leaning against the stock ahead of the announcement. Daily short-sale volume ratios for ZTS – the proportion of trading volume attributable to short sales, where investors sell borrowed shares betting the price will fall – stayed low and fairly stable through late July and early August 2026, ranging from 0.29 to 0.583, according to FINRA’s daily short sale volume data. The lowest reading of that stretch, 0.29, came on 29 July; the ratio ticked up to 0.30 on 12 August, the day before the EUA news broke, but that was still well within the range seen over the prior fortnight. None of it points to unusual bearish positioning building into the announcement.

What happens next is largely a regulatory and commercial question rather than a market one. The FDA’s emergency authorisations for New World screwworm products are, by design, time-limited responses to an active outbreak, and the agency’s tracking page shows it has been willing to add new products roughly every few weeks as the outbreak has progressed. Investors and veterinarians alike will be watching whether Zoetis reports actual uptake of Simparica Trio for this new use when it next updates the market, and whether the FDA extends similar emergency clearances to further products as the screwworm’s spread continues to test the animal-health sector’s response.

This article is for information only and is not investment advice or a recommendation to buy or sell any asset. Markets move quickly; figures are correct as sourced at the time of writing. Always do your own research before making financial decisions.