Disease ecology classes were conducted at two residential middle school summer camps held at a university--a camp for local youth who paid tuition and a free camp for youth from statewide underserved communities including Native, low-income, and rural. Disease ecology is defined as the ecological study of host-pathogen interactions within the context of their environment and evolution. The classes were created by a grant-funded program for disease ecology designed to increase middle school youths' interest, confidence, and identity in STEM, and their understanding of disease ecology. Undergraduate researchers were recruited to develop and teach lessons in disease ecology. This paper outlines the project's elements, effects on undergraduate students and middle school youth, and lessons learned. This study has three key findings: 1) Undergraduate participants increased their confidence and interest in science outreach and their understanding of disease ecology, 2) STEM identity increased in both underserved middle school youth and a comparison youth group, 3) Both underserved and comparison group middle school youth increased their understanding of disease ecology, Native culture, traditional knowledge about food, how to be healthy where they live, and how science can help their communities.