As a graduate student, she discovered and characterized the first identified chemosensory receptors in C. elegans (roundworm). Next, she helped launch a start-up biotech company for four years. After this company went public, Dr. Troemel returned to academic research as a postdoc, where she identified the first natural pathogen of C. elegans named Nematocida parisii. This pathogen defines a new genus and species of microsporidia, which are priority pathogens of medical and agricultural significance. Microsporidia can be found in water supplies and can cause a variety of infections, known as microsporidiosis, which affect people with weakened immune systems. The parasites can infect the lungs, kidney, brain, muscles, eyes, sinuses, or intestines, and can cause gallbladder disease and a debilitating array of gastrointestinal symptoms, including chronic diarrhea.