Tracking the Path of New World Screwworm 

ARS is employing innovative modeling techniques to predict where New World screwworm infestations may emerge in the U.S. 

By: Todd Silver
Email: arspress@usda.gov

New cases of New World screwworm have recently surfaced in the United States, and with them the critical need to track its paths to determine where future infestations may occur. Researchers at the U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS) are employing predictive models as part of a forward-thinking approach to manage New World screwworm. This strategy allows USDA agencies to act earlier, respond faster, and direct resources where they are needed the most to protect U.S. livestock, pets, and wildlife.   

“Everything in modern agriculture and pest management is moving toward precision intervention and that includes the Sterile Insect Technique (SIT) for control of New World Screwworm. Modeling their movement and using this information for optimal placement maximizes our impact and hastens eradication” said Dr. Scott Hutchins, Under Secretary for Research, Education, and Economics at USDA.  

Predictive models use advanced analytic tools and artificial intelligence (AI) to interpret ecological, environmental, and historical information to predict where New World screwworm is likely to become established and the potential pathways it may follow to spread. The models look at the following factors: 

• Ecological and habitat suitability to identify landscapes and habitats that naturally support New World screwworm and map the regions in which this pest could move through favorable environments. 

• Environmental conditionsto monitor key factors such as temperature and precipitation, because they can directly influence New World screwworm survival, reproduction, and spread. Changes in the weather, such as seasonal changes, can raise or lower the risk of New World screwworm infestations. 

• Historical outbreaks and patterns to anticipate where New World screwworm may move next. The models also review past management efforts, highlighting actions that effectively slowed this pest and those that were not successful. This information will aid in the development of new mitigation strategies.  

“We now have at our disposal incredible tools to help re-eradicate New World screwworm that were not available to our predecessors, including advanced AI and predictive modeling tools that can be employed to help us forecast where New World screwworm infestations are likely to pop up,” said Kim Lohmeyer, Director of the ARS Knipling-Bushland Livestock Insects Research Laboratory in Kerrville, TX. “Having any kind of forewarning system that helps guide surveillance and management decisions is a game changer in our fight to respond quickly to this urgent pest.”  

The integrated modeling system will guide researchers, ranchers, and public health officials in implementing strategic and targeted approaches in order to be prepared for possible outbreaks, and to enable responders to stay ahead of New World screwworm.  The modeling system will help strengthen USDA’s multipronged approach to combatting New World screwworm, which includes: 

• Strategically increasing surveillance efforts and directing resources such as aircraft, personnel, fly traps, and sterile insects to the areas where they offer the greatest protection and at precise times to cause the greatest impact. This targeted allocation speeds up detection and strengthens prevention efforts. 

• Implementation of SIT strategies. Success of the benchmark SIT program depends on knowing when and where to release sterile flies. SIT is a safe and proven technique for controlling New World screwworm populations and consists of releasing sterile flies into areas where New World screwworm is present or likely to spread. USDA uses insights from the models to identify optimal locations, timing, and the number of sterile flies to release for the most effective application, to interrupt their reproductive cycle and spread.  

• Assessing prevention strategy effectiveness. The models enable USDA agencies to assess how effective current and planned prevention strategies are at slowing the movement of New World screwworm in the U.S. and to make timely adjustments as needed. 

“ARS developed predictive New World screwworm models that incorporate historic data like habitat use, host preferences, and environmental conditions into a science-based platform that are already being utilized to select areas for increased livestock and wildlife surveillance, adult fly trapping, and for implementing SIT,” said Lohmeyer. “However, these models cannot predict every scenario, especially those impacted by unpredictable variables like people transporting infested animals.” 

Livestock owners should remain vigilant and never move an animal that exhibits signs of infestation or that is suspected of being infested. Livestock owners should work with their state animal health officials and ensure they are following all requirements before moving any livestock or wildlife in and out of infested areas. 

If you spot signs of New World screwworm infestation in animals, report it to the appropriate responding official by visiting the USDA New World screwworm reporting page.  

To obtain the latest information and updates about New World screwworm, visit screwworm.gov.