Cattle Q&A with Brinda Dass, GeneConvene Global Collaborative
Cattle Q&A with Brinda Dass, GeneConvene Global Collaborative
Tags: Agriculture, Gene drive synthetic, Genetic biocontrol, Pest managementTyrell Marchant, Progressive Cattle, 2025.
What factors have led to the northward spread of New World screwworm (NWS) over the past year after so many decades of successful eradication in Mexico and the U.S.?
DASS: The northward spread of NWS after decades of eradication reflects a convergence of biological, environmental and programmatic factors. Climate change and increasing temperatures have created favorable conditions for pupal survival and year-round reproduction, enabling rapid reinvasion from subtropical regions. NWS biology – especially females’ ability to lay multiple waves of eggs in wounds – allows populations to surge quickly even from small footholds. High-density livestock practices and insufficient inspection of animal trade further accelerate spread, with smuggling through the Darién Gap undermining surveillance. Wildlife, pets and humans act as reservoirs, compounding detection challenges. Sterile insect technique (SIT), historically successful, has been overwhelmed: Production of sterile flies cannot match population growth, forcing control lines northward. Budget constraints, political disputes and reduced funding have further weakened monitoring and response systems. Together, these dynamics explain how a long-maintained eradication barrier collapsed, allowing NWS to expand northward at alarming speed.
