Lexington Student’s Malaria Model Wins $50,000 Davidson Fellows Scholarship

Public-health systems around the world have long struggled with the challenge of maximizing limited resources for disease prevention. Now, a 16-year-old student from Massachusetts has developed an innovative mathematical model that suggests existing supplies of insecticide-treated mosquito nets could achieve double their current impact through smarter allocation. Rajarshi Mandal, a rising junior at Lexington High School in Lexington, Massachusetts, built the simulation to evaluate how distribution strategies affect malaria transmission. According to an online report by the Davidson Institute, his work earned him a prestigious $50,000 Davidson Fellows Scholarship.

Globally, approximately 200 million insecticide-treated nets are distributed annually, with allocations predominantly based on population size. Mandal set out to investigate whether optimizing where those nets are sent could prevent more infections without requiring an increase in manufacturing or supply volumes. His ordinary differential equation model simulates real-world conditions more closely than standard population-based approaches by factoring in insecticide resistance, seasonal variations in transmission rates, and the gradual physical degradation of the nets over time.

The inspiration for the project stemmed from an unusual source. Mandal noticed documentary footage showing fishermen using donated mosquito nets as makeshift fishing material because the mesh was readily available when conventional gear was not. That image prompted him to examine the disparities between high-level distribution plans and actual conditions on the ground. His initial research utilized a machine-learning framework known as a Deep Q Network. However, that system encountered instability because allocation decisions produced noisy results and delayed benefits, making it difficult for the algorithm to determine reliable value estimates. Consequently, Mandal shifted to a different architecture that directly scored potential allocations.

The research also required overcoming complex epidemiological hurdles. Early iterations of the simulation frequently drove infection levels down to zero, which failed to mirror reality in endemic areas. Guided by academic researchers, Mandal investigated backward bifurcation—a mathematical phenomenon explaining how disease transmission can persist under conditions where simpler models might predict complete eradication. He derived the simulation's reproduction number to confirm that it could successfully sustain transmission at realistic mosquito-biting rates, incorporating seasonality, insecticide resistance, and logistical hurdles.

Mandal's focus extends beyond theoretical statistics to the tangible human toll of malaria, including missed schooling, lost work hours, and disruptions to family and farming responsibilities. He also noted the real-world logistical barriers that affect public-health interventions, citing a photograph of an overturned transport truck in the Democratic Republic of Congo with mosquito nets scattered across the ground. While mathematical models cannot fix transport accidents or remote delivery challenges, Mandal's research demonstrates that they can optimize decision-making for the resources that successfully reach their destinations.

Outside of his scientific research, Mandal pursues advanced studies in mathematics and computing. He is also an accomplished musician who has performed twice at Carnegie Hall, and he maintains active interests in volleyball, skiing, mountain biking, and karate, holding a black belt in the discipline. The Davidson Fellows Scholarship provides the young researcher with both financial support and a broader public platform as he continues his academic pursuits.