As the Southern U.S. continues to navigate cases of New World screwworm (NWS), the Foundation for Food & Agriculture Research (FFAR) and the University of Notre Dame are investing $140,389 in a Rapid Outcomes from Agricultural Research (ROAR) grant to evaluate whether an existing drug can be repurposed to kill screwworm larvae.
The reemergence of NWS is now threatening U.S. livestock production, wildlife and agricultural trade. Reports of reduced effectiveness of some commonly used treatments in South America, combined with the limited number of approved control options, underscore the need to evaluate new approaches. This urgently needed research could provide producers and veterinarians with an additional tool to protect livestock and strengthen U.S. preparedness.
Led by Dr. Lee Haines, associate research professor of biological sciences at the University of Notre Dame, and Dr. Álvaro Acosta-Serrano, professor of biological science at the University of Notre Dame, a team of researchers are evaluating whether nitisinone, a U.S. Food & Drug Administration (FDA)-approved drug with an established safety profile in humans, can effectively kill screwworm-related blowfly larvae. Research breakthroughs over the past five years have shown that nitisinone also kills several blood-feeding arthropods (including mosquitoes, ticks, kissing bugs, bed bugs, tsetse flies and stable flies) by blocking a key enzyme they need to digest blood, which is also found in screwworms.
“We’ve already demonstrated nitisinone’s transformative ability to kill other blood-feeding insects, and applying this knowledge to screwworms opens up a timely new frontier in livestock protection,” Haines said. “Growing up on a farm, I watched our animals suffer from other blood-sucking insect pests every summer, and that experience taught me early on just how much these tiny predators can wear an animal (and the farmer) down. We are eager to build on our recent breakthroughs in vector-borne diseases to develop a much-needed and complementary tool for protecting U.S. livestock and producers from the screwworm populations expanding across the country.”
Using the closely related secondary screwworm as a model, the team is testing nitisinone’s ability to kill screwworm larvae and adults, with a primary focus on larval toxicity and the drug’s potential to target screwworms in the wound environment. Researchers are also establishing methods to assess how nitisinone affects fly growth, reproduction and survival. The results will provide critical data to establish the dosing and additional parameters needed to guide future primary screwworm trials.
FFAR is investing in this research to evaluate a novel treatment strategy for NWS, providing the scientific foundation for new tools to improve producer preparedness, animal health and response efforts. The ROAR grant provides rapid-response funding for a pilot study to establish and refine research methods and determine nitisinone’s toxicity to secondary screwworm, with a particular focus on larvae and its potential use to treat the wound environment. The findings and methodologies developed through this project will provide a foundation for subsequent research at a larger scale, including studies of additional applications of nitisinone and its effectiveness against adult flies. This research supports USDA’s research priority on Protecting the Integrity of American Agriculture from Invasive Species.
FFAR’s ROAR program rapidly funds research and outreach in response to emerging or unanticipated threats to the U.S. food supply or agricultural systems.
