During a lunch table discussion in 2009 at the U.S. Department of Agriculture’s (USDA) Wildlife Services-National Wildlife Research Center (WS-NWRC), visiting Australian scientists were excited to share news about a patent under review by the U.S. Patent and Trade Office. It was for a new technology they developed involving sodium nitrite— a salt commonly used to preserve meat. They believed the technology could potentially revolutionize invasive feral swine management by selectively and humanely removing unwanted feral swine. Feral swine are a major pest species in Australia, the United States, and many other countries.
Intrigued by this discovery, an international collaborative team was formed to bring the new technology to market. Formalized under a 2013 Cooperative Research and Development Agreement, the team included scientists at the Australian Invasive Animals Cooperative Research Centre (IACRC); Dr. Linton Staples at Animal Control Technologies, Australia (ACTA, Founder and Managing Director), WS-NWRC scientists, and Texas Parks and Wildlife Department. Their goal was to further develop a sodium nitrite bait and bait station to control feral swine populations.
The groundbreaking technology is a microencapsulated form of sodium nitrite that masks its salty taste in a bait. When a feral swine unknowingly eats a high dose of sodium nitrite, the compound reduces its blood's ability to transfer oxygen to its tissues, a condition known as methemoglobinemia. The mode of death is similar to carbon monoxide poisoning. If enough sodium nitrite bait is eaten, the feral swine gets faint, is rendered unconscious, and quickly dies. In most cases, feral swine die within 2.5 to 3 hours after eating a lethal dose.
Initial collaborations focused on studies with captive feral swine to determine the toxicant’s effectiveness and humaneness. Scientists were also interested in the toxicant’s potential impact to other species that could be accidentally exposed to the bait. Tests showed that sodium nitrite degrades quickly when exposed to environmental elements, such as microorganisms, sunlight, heat, and moisture. Furthermore, most sodium nitrite is broken down within the animal’s body before it dies, making their carcasses safe for scavengers, such as coyotes and vultures. Scientists, however, were still concerned about potential risks to other, nontarget species if they ate the bait directly.
In 2018, the U.S. Environmental Protection Agency (EPA) granted an Experimental Use Permit for a field trial of the sodium nitrite bait called HOGGONE®. Feral swine are messy eaters, and during the field trial they spilled toxic bait on the ground near bait stations. Researchers noticed that bait crumbs left outside bait stations by feral swine posed a risk to nontarget species, mainly seed-eating birds.
“We worked with ACTA to reformulate the bait to reduce nontarget risks by increasing its palatability to feral swine and reducing spillage,” explains WS-NWRC research wildlife biologist and feral swine project leader Dr. Kurt VerCauteren. “We also reassessed our baiting strategies and designed a durable, lightweight, and reusable bait station that reduced spills and prevented access to bait by nontarget species.”
Large-scale field trials in Texas and Alabama during 2021 put the revised bait formulation, known as HOGGONE® 2, to the test. The new bait was paired with a swine-specific bait station and scare devices to deter birds. The trials resulted in a 91-percent reduction in feral swine during 1 night of baiting and no nontarget species deaths. Additional trials are planned for February 2023. If the trials are successful, USDA will apply for a registration for year-round use of the sodium nitrite toxic bait for feral swine in the United States. The EPA will have 25 months to review the application.
HOGGONE® is registered in Australia for use in managing feral swine populations and approved under permit in Canada for emergency disease suppression. The product is currently being trialed by ACTA in Canada, Argentina, and New Zealand. ACTA is currently exploring options for U.S. manufacturing and distribution capabilities for HOGGONE 2.
In addition to HOGGONE®, this partnership is also developing a diphacinone-based bait for managing invasive mongooses. Small Indian mongooses are invasive predators in many tropical areas including Hawaii, Puerto Rico, and the U.S. Virgin Islands. Invasive mongooses negatively impact native ecosystems, can carry leptospirosis and rabies, and cause sanitation issues in food processing facilities and public areas. Finding a bait that mongooses will eat and has a long shelf life is challenging. In 2021, NWRC and ACTA established a CRADA to test mongoose acceptance and sensitivity to ACTA’s proprietary bait matrix laced with a rodenticide. The results of this laboratory study were promising. At APHIS’ request, EPA issued an Experimental Use Permit to field test the bait on mongooses in Hawaii in 2023. If this test is successful, APHIS will pursue a U.S. pesticide registration. ACTA hopes to manufacture and sell the new mongoose baits within the U.S. and other foreign markets.
For additional information, please contact the WS-NWRC Technology Transfer Coordinator (970-266-6158, [email protected]).
Story submitted by USDA. Mention of companies or commercial products does not imply recommendation or endorsement by USDA over others not mentioned. USDA neither guarantees nor warrants the standard of any product mentioned. Product names are mentioned solely to report factually on available data and to provide specific information.
Photo caption: Invasive feral swine cause billions of dollars in damages worldwide to agriculture, natural resources, and property. They can also spread disease, threatening human health and safety.