Merging Math with a Mission

Calistus N. Ngonghala doesn’t know how many times he’s had malaria. It was so common growing up in rural Cameroon in the 1980s—the fever, chills, and nausea routinely keeping him home from school—that he can’t put an exact number on it.

He does know he is one of the lucky ones.

The World Health Organization has estimated the parasitic disease, most often transmitted by the bite of an infected mosquito, kills roughly 11,000 people in his country every year. When Ngonghala was younger, that number was much higher.

“I watched so many people, including my relatives, die of very simple and preventable diseases like malaria,” Ngonghala told a crowd of Radcliffe fellows last fall. Then he told them how he has been fighting back. An associate professor of mathematical biology at the University of Florida, Ngonghala has spent much of his life using math to both track infectious diseases and identify the best methods for containing and preventing their spread.

At Radcliffe, he is again deep in that work, he explained in a recent interview, using mathematical models and data analytics to study the complex relationships between socioeconomic factors, environmental changes, human behavior, and the spread of malaria and COVID-19. Understanding those connections is central to saving lives, Ngonghala argues, recalling the early stages of COVID-19, when “most of the mathematical models that were developed which failed to account for these kinds of connections also failed to predict COVID-19 trajectories or dynamics accurately,” resulting in more loss of life.

A Love of Math and a Mission

In grade school, Ngonghala’s love for math was born of self-preservation. He was required to solve a set of 30 simple calculations in 30 minutes each morning. The penalty for every wrong answer was a whack on the hand. “To be very honest, that worked really well for me,” he recalls, “because I feared nothing more than the touch of a cane.”

Fortunately, his mother was more forgiving, happily accepting her son’s help tallying up customer tabs and coordinating bills in her small, local bar. Gradually, Ngonghala realized he wanted to pursue his passion for math and help his community thrive. “I started thinking about malaria,” he says, “this terrible problem that my people were facing and wondering how I could contribute.”

His answer came at Cameroon’s University of Buea, where his “mathematical biology” class taught by Gideon A. Ngwa showed him how he could use his favorite subject to study the transmission dynamics of infectious diseases. Ngonghala earned his undergraduate and master’s degrees in mathematics at the university in 1997 and 2000 respectively, focusing his graduate research on the mathematical modeling of malaria transmission. In 2011, he received his PhD in math at West Virginia University in Kenneth Showalter’s Physical Chemistry Laboratory, conducting chemical experiments and expanding his understanding of how to model chemical systems.

For the mathematician, Harvard is familiar academic ground. Before beginning work at the University of Florida, he conducted postdoctoral research at Harvard Medical School’s (HMS) Department of Global Health and Social Medicine with the HMS professor Matthew Bonds, the same department where Ngonghala is currently a visiting associate professor.

Modeling COVID-19

At the start of his career, much of Ngonghala’s focus had been on malaria and developing modeling frameworks to explain complex synergistic feedback between infectious diseases and economic growth, with the goal of improving public health, identifying pathways for breaking vicious cycles of disease and poverty, and guiding vulnerable populations toward sustainable growth trajectories. Then came March of 2020. He was at Arizona State University continuing work on malaria modeling with his collaborator, Abba Gumel, when they noticed a worrying spike in the number of people contracting a deadly new virus.

“We thought this was so urgent with not a lot known and that, maybe, through mathematical modeling, we could provide some insights that could also guide policy.” Guide they did. Their paper, written with a group of collaborators that included Bonds, presented a mathematical assessment of the effectiveness of social distancing, face masks, quarantines, and contract tracing that became a widely cited source for states and federal agencies. Later, as lockdowns and mask mandates encountered public pushback, Ngonghala began considering how “hesitance to adopt certain measures” and the impact of voluntary versus mandatory restrictions could affect a disease’s dynamics, questions he continues to explore at Radcliffe.

During his fellowship, Ngonghala will also study the economic effects of disease. He points to the countless officials who struggled with the difficult decision to either enforce COVID-19 lockdowns and suffer economic consequences, or to keep businesses running and struggle with a sicker population. “So many governments were faced with that trade-off, which just highlighted the fact that you cannot study diseases without thinking about the socioeconomic factors,” says Ngonghala. “So my research, too, has been focused on trying to understand these feedbacks between diseases and economic growth.”

While at Radcliffe, he will also explore how climate change may play a role in the transmission of COVID-19, building on his earlier work that examines how temperature changes affect the spread and control of the Zika virus and malaria in different parts of Africa.

Future Leaders in Math

For Ngonghala, sharing his knowledge and findings has become almost as important as his work and research focused on the transmission of COVID-19 and malaria. In addition to helping fight infectious diseases, he is eager to help future generations of budding mathematicians who may be unaware of just how far the field can take them.

“One of the things that I’ve been embarking on over the years has been to take part in training workshops, mostly in Africa, to educate younger people on how it’s so important to take on math and how math can be useful in addressing so many problems, not only in public health but a range of other issues,” says Ngonghala. “I want students to know that contrary to the belief that mathematics is abstract and impractical, it provides powerful tools for solving complex problems across diverse real-world fields.”

Colleen Walsh is a freelance writer.

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