June 16, 2016 — As an undergraduate working in malaria researcher Dyann Wirth’s lab at Harvard T.H. Chan School of Public Health, Caleb Irvine was curious why malaria transmission was on the uptick in the Thiès region of Senegal, in spite of efforts to control the disease there. In July 2014, he traveled there to study the DNA of the most common malaria parasite in the region and uncovered important new information about recent genetic changes in the parasite population. In recognition of his efforts, he was honored with a Harvard College award called the Hoopes Prize.
Irvine was following up on the Wirth lab’s recent finding of a rebound in genetic diversity in the most prevalent malaria parasite in the region, Plasmodium falciparum—a potentially worrisome trend that suggested problems with malaria control efforts in Thiès.
But Irvine’s finding—that the parasite’s genetic diversity had declined following its rebound—“provided new evidence showing that fluctuations in genetic diversity might not necessarily indicate a problem with malaria control efforts,” explained Rachel Daniels, research scientist in the Department of Immunology and Infectious Diseases, who served as a mentor to Irvine in the Wirth lab along with principal research scientist Sarah Volkman. “Caleb’s results raised interesting questions that we hope to further explore about how parasite populations may change in response to pressure—both from the natural environment and human interventions.”
Irvine’s novel approaches and observations “will likely result in a major study,” said Wirth, Richard Pearson Strong Professor of Infectious Diseases and chair of the Department of Immunology and Infectious Diseases, who nominated Irvine for the prize. “In addition, the data Caleb produced will be used by the Ministry of Health in Senegal to aid its malaria elimination efforts. He has made profound contributions to efforts to translate basic research into immediate, real-world applications.”
The Hoopes Prize recognizes outstanding scholarly work or research. This year, 64 Harvard College seniors, including Irvine, received the $4,000 prize.
A ‘life-changing’ experience
Irvine, who graduated in May with a bachelor’s degree in molecular and cellular biology and a secondary in global health and health policy, first spent time in Africa during the summer after his junior year in high school, when he volunteered at an elementary school in Shirati in western Tanzania, working on projects like a rainwater-fed handwashing station and a geodesic dome play structure. He also toured nearby Shirati Hospital, which he called a “life-changing” experience. Seeing sick, malnourished patients with treatable diseases, he realized how urgently help was needed and started thinking about a career in global health and infectious diseases.
His interest in the field was spurred further when, as a Harvard freshman, he took a course in global health case studies—“one of my favorites across all four years,” he said—co-taught by four professors from Harvard Medical School’s Department of Global Health and Social Medicine, including Paul Farmer, chief strategist and co-founder of Partners in Health, and Arthur Kleinman, Anne Becker, and Salmaan Keshavjee. The summer after his freshman year, Irvine returned to Tanzania to volunteer at Shirati Hospital. He saw the toll taken by malaria, an endemic disease in that country. “It seemed like such a complex and difficult disease to address that I wanted to learn more,” he said. Back at Harvard, when he learned about the summer internship in research in Wirth’s lab—one that included research in Senegal—he said, “I couldn’t think of anything that I would enjoy more.”
Molecular barcode
To learn more about why malaria transmission had rebounded in Thiès, Irvine extracted P. falciparum DNA from the blood of malaria patients in the region and grouped the samples according to their “molecular barcode”—a method developed by the Wirth lab to identify and track individual parasites. Categorizing the samples in this way enabled Irvine to understand the level of genetic diversity in the samples.
Irvine’s findings “are significant to the field, as they offer new information on the genetic characteristics of parasite populations in an area that is actively working towards malaria elimination,” said Daniels. “Caleb showed how to quickly track and report on these changing trends, which could allow government agencies to tailor their malaria control efforts more effectively.”
Irvine now plans to spend a few years as a post-bachelor fellow at the Institute of Health Metrics and Evaluation in Seattle, and is hoping the experience will help him decide whether to go into global health research long-term or apply to medical school with a focus on global health and infectious diseases. In the meantime, he is grateful for having had the opportunity to conduct research in the Wirth lab. “It feels great to know that my work is going to have an impact for such an important cause,” he said.
photo: Sarah Sholes