An outbreak of New World screwworm has recently been spreading across Mexico, after more than 30 years of absence. The sterile insect technique, which consists of the massive release of sterilized males, has proven to be one of the most efficient methods for controlling the screwworm pest. However, given the limited number of sterile males available, improving the release strategy is critical. We propose a mathematical model of population dynamics adapted to the biology of Cochliomyia hominivorax and derive a feedback control function to determine the number of sterile males to release. We further construct a Luenberger observer to estimate wild fly populations from infected animal counts--the variable monitored by Mexican sanitary authorities--enabling field implementation of the control function. We show that eradication is achievable within approximately 60-100 weeks and that eradication time is governed primarily by the intrinsic biology of the system rather than by infestation magnitude. We then extend the model to a spatially explicit framework and show that when sterile male releases are applied at the outbreak focus and within a 120 km radius, eradication of the pest is attainable.
1. 新世界螺旋蝇疫情在消失30多年后，近期在墨西哥蔓延。由大规模释放绝育雄蝇构成的绝育昆虫技术，已被证明是控制螺旋蝇害虫最有效的方法之一。然而，鉴于可用的绝育雄蝇数量有限，改进释放策略至关重要。我们提出了一种适应螺旋蝇生物学特性的种群动力学数学模型，并推导出反馈控制函数以确定绝育雄蝇的释放数量。我们进一步构建了龙伯格观测器，通过受感染动物数量（墨西哥卫生当局监测的变量）来估计野生蝇种群，从而实现控制函数的现场应用。我们证明，在大约60至100周内可实现根除，且根除时间主要由系统内在生物学特性决定，而非侵扰程度。随后，我们将模型扩展到空间显式框架，并表明当在疫情爆发中心及120公里半径范围内释放绝育雄蝇时，可实现该害虫的根除。
Reyes, R. et al. · CC-BY 4.0