Drawn to Tropical Medicine by a Mentor’s Inspiration
Kitamura:
Dr. Moriyasu, you have a diverse background, from holding a degree in economics to conducting research in parasitology. Could you tell us about your career path?
Moriyasu:
I first entered university with the goal of becoming a clinical laboratory technician. Back then, there was no unified “School of Health Sciences” as we have now—instead, each national university had what was called a “College of Medical Technology.” I attended one such program at Kyushu University. It was a three-year course designed to train co-medical staff, such as nurses, clinical laboratory technicians, and radiological technologists. These programs have now been integrated into the faculties of health sciences at medical schools. I studied there for three years and obtained my certification as a clinical laboratory technician.
What initially inspired me to pursue a career in healthcare was seeing the Ethiopian famine when I was in elementary school. That was a time when mass media was becoming an influential tool in social activism, and the dire situation in Ethiopia was widely covered around the world. Many people, including those in Hollywood, mobilized to help, and in the U.S., the song “We Are The World” became a symbol of this movement. In Japan too, attention to global social issues was growing, and as a teenager, I was deeply moved by the images and news. I thought, “The world is one—there must be something I can do.” Even as a child, I felt that medical care was one of the most needed areas, and so I decided to pursue a path in the medical field.
It was at university that I first encountered the Tropical Medicine Research Society. At the time, Kyushu University had an active chapter, and I met peers with similar aspirations, which was highly stimulating.
Kitamura:
Was that your entry point into tropical medicine?
Moriyasu:
Yes, it was. However, at that time, the field of tropical medicine was in decline. In fact, tropical medicine had nearly disappeared in Japan once. Infectious diseases like schistosomiasis, filariasis, and malaria—what we typically call tropical diseases—were once present in Japan and needed to be addressed. Historically, research in tropical medicine was also part of colonial governance. As Japan expanded into Asia, tropical disease control became a key concern, and research progressed accordingly. Additionally, many of these infectious diseases existed domestically, so they were considered internal issues as well. However, with Japan’s defeat in World War II, its overseas territories were lost, and the colonial motivation for tropical medicine disappeared. As public health improved through postwar economic growth, tropical diseases and parasitic infections gradually ceased to be major societal issues within Japan. When I entered university, parasitology departments at national universities across the country were being closed one after another.
Kitamura:
I had no idea that such a period had existed.
Moriyasu:
Yes, and by the time I entered university, the Tropical Medicine Research Society was practically inactive. But coincidentally, in the year I enrolled, a group of students like me who were eager to engage globally joined the society. About seven or eight of us from the same year joined, and the following year, around ten more first-years joined as well. Suddenly, the society was revitalized. It transformed into a circle that attracted students who aspired to provide medical aid overseas.
At that time, the Department of Parasitology in the Kyushu University Faculty of Medicine was led by Professor Isao Tada, who became the mentor who influenced me most deeply. Professor Tada also served as an advisor to the Japanese Society of Tropical Medicine. He would share stories of his research in Guatemala and the Ryukyu Islands, and we students were inspired to think, “Someday, I want to feel the tropical breeze myself!” and “Let’s all go to the tropics someday!”
One particularly memorable story from Professor Tada was about his survey work in the Ryukyus. During the American occupation of Okinawa, he obtained permission from the U.S. military to conduct fieldwork on filariasis and visited the area with students. That Okinawa expedition later became the origin of the Kyushu University Tropical Medicine Research Society. We had the opportunity to hear from professors who participated as students and even saw a documentary produced by a television station that followed the expedition. It was all so exciting. Just as Professor Tada passed that sense of wonder to us, I now hope to inspire the next generation with the same passion for tropical medicine.
Dr. Moriyasu holding a baby who came along to a parents’ meeting to discuss toilet construction.
A Multidisciplinary Career—Putting It to Use
Kitamura:
What path did you take after graduation?
Moriyasu:
After graduation, I worked as a clinical laboratory technician at Nagasaki Atomic Bomb Hospital. However, over time I began to feel unsatisfied with the routine of testing specimens in the lab day after day. I wanted to study more, so I consulted with Professor Tada, who introduced me to Professor Aoki in the Department of Parasitology at the Institute of Tropical Medicine, Nagasaki University. I was quite nervous when I first visited Professor Aoki’s office—I honestly don’t remember what I said—but afterward, I began working with Dr. Fujimaki, conducting experiments at night to test the anti-parasitic effects of compounds. These experiments involved observing the effects of drugs on the filarial worm Pahang Schistosomiasis* which is retrieved from jirds. Although the lab work was fascinating and rewarding, I began to feel a stronger desire to engage with people and contribute more directly to infectious disease control on the ground.
That led me to realize that combating infectious diseases requires more than just medical knowledge—it also requires an understanding of broader societal factors. So, I decided to study economics. Around that time, Nagasaki University launched an evening economics program for working professionals. The idea of being able to work and study at the same time appealed to me, so I enrolled and completed the four-year program, earning a bachelor’s degree in economics.
*Pahang Schistosomiasis: A filarial worm that infects humans but has rodents as its definitive host.
Kitamura:
So you earned your economics degree as a working adult! What did you study there?
Moriyasu:
In the Faculty of Economics, I joined a lab that used mathematical modeling to improve operational efficiency and support decision-making. My main interest was in evaluation metrics for nonprofit organizations operating in developing countries. Generally, such organizations set numerical targets for their projects, but it’s difficult to clearly quantify the effectiveness or outcomes. I sought methods that could more accurately capture efficiency and areas for improvement, rather than relying solely on numerical goals.
To deepen my research, I entered graduate school. I asked the nonprofit organization Ruchina Communication Yaponessia, which was active in Cambodia, to let me join their work and help evaluate their project activities. That fieldwork formed the basis for my master’s thesis in economics.
Kitamura:
Could you tell us more about the specific method you used to evaluate the Cambodian project?
Moriyasu:
I used a method called Data Envelopment Analysis (DEA), which measures the relative efficiency of multiple entities based on the ratio of inputs to outputs. The basic idea is to evaluate how much output was generated from the resources invested. In the Cambodian project, agricultural cooperatives were being organized in rural communities and microcredit programs were being introduced. My study aimed to include hard-to-quantify elements and differently scaled indicators to conduct comparative evaluations across cooperatives.
For example, it might seem that large cooperatives have an advantage because they have more resources, but DEA revealed that smaller cooperatives outperformed larger ones in certain areas. I also devised ways to quantify qualitative aspects such as the leadership of the cooperative chairperson and include them as inputs.
Kitamura:
That’s fascinating—so many ways to evaluate efficiency! You eventually earned a PhD in parasitology. How did you transition from economics to parasitology?
Moriyasu:
After completing my master’s in economics, I spent about 10 years as a full-time homemaker due to marriage and childbirth. Then I was invited by Professor Shinjiro Hamano, who had become a professor at the Institute of Tropical Medicine, Nagasaki University. He told me about a new graduate program called the “Leading Program.”
I had known Professor Hamano since my days at the Tropical Medicine Research Society at Kyushu University. The Leading Program was a doctoral course established by the Ministry of Education to cultivate globally active leaders through interdisciplinary education and collaboration among academia, industry, and government. Nagasaki University had just launched a program focused on developing leaders in infectious disease control.
What appealed to me was that it wasn’t a conventional research training course, but rather a program designed to cultivate leaders capable of addressing social challenges beyond disciplinary boundaries. That resonated with me, and I took the entrance exam. I was fortunate to pass and went on to earn my PhD in parasitology in Professor Hamano’s lab.
Kitamura:
What kind of work are you doing now?
Moriyasu:
Currently, I focus on behavioral change as my research theme. Behavioral change involves various elements—education, behavioral tendencies, psychological factors—and I’m working to integrate these in my research. I’m also participating in Professor Hamano’s project on schistosomiasis, exploring how human behavior affects infection and how we can alter that behavior to prevent disease.
For example, in diseases like schistosomiasis, which involve repeated infection, drug treatment can temporarily reduce prevalence. But as long as environmental sources of infection remain, the disease will not disappear. If people continue living the same way, they’ll keep getting infected. Of course, developing drugs and diagnostics is crucial, but that alone is not enough. Ultimately, we need to shift people’s lifestyles so they avoid infection.
Infections occur where the lifecycle of a pathogen intersects with human behavior. Our task is to determine where to sever that overlap. In areas without clean water infrastructure, telling people “Don’t touch lake water” is impractical—water is essential for daily life. In such cases, the focus shifts to defecation practices. If waste doesn’t enter the water, infection risk drops. Even without toilets, encouraging people to defecate away from water sources can help reduce infection. The key is finding practical, acceptable solutions for local communities. That requires listening to their voices and understanding that their everyday logic may be very different from ours.
Kitamura:
I see. Understanding the essence of these issues is harder than it sounds.
Moriyasu:
That’s why I want to incorporate more practical applications from behavioral science and psychology. In a toilet promotion project we’re conducting in Kenya, we work alongside the community. We don’t simply build toilets for them—we discuss what kind of toilet they want and help them develop a system to manage it themselves.
Furthermore, I believe that policy and broader societal movements are critical. In addressing neglected tropical diseases (NTDs), it’s not just about controlling the diseases—it’s also about how we approach policymaking and public campaigns. I learned this from another mentor, Dr. Kazuyo Ichimori, who worked for many years at the WHO on lymphatic filariasis control. She taught me that science alone isn’t enough—policy plays a vital role in infectious disease control.
Children, parents, teachers, and villagers all dig the toilet’s sewage tank by nearly 2 meters.
Kitamura:
What are your dreams or goals for the future?
Moriyasu:
I want to support the application of research outcomes from Japanese tropical medicine researchers to society. Currently, I work in a department at Nagasaki University that promotes internationalization, supporting the development of frameworks for international collaborative research and working toward the globalization of education. Nowadays, research projects are rarely carried out by a single researcher—they increasingly require interdisciplinary collaboration. It’s not just researchers either; cooperation among academia, industry, and government is becoming essential. I hope to contribute to the field of tropical medicine by building frameworks for such cross-sector projects and managing them.
Kitamura:
When bringing together people from different fields, I imagine it can be difficult to reconcile different perspectives. Do you have any tips on how to achieve cooperation among such diverse experts?
Moriyasu:
As you can probably tell from my background, I’ve done many different things. Some might say I lack a specific expertise, but I see that diversity as a strength. I try not to look at things solely from one disciplinary viewpoint. I make a conscious effort to understand the different positions and perspectives involved, and to engage in persistent dialogue so that all sides can come to an agreement and move forward together.
Kitamura:
What do you find rewarding or enjoyable about your current work?
Moriyasu:
I really enjoy talking with different people. Just having the opportunity to meet people from various fields is deeply rewarding. Another source of fulfillment is educating young people. That includes not just academic teaching, but also “sharing experiences.” For example, when I travel abroad with students and we see landscapes or encounter values they’ve never experienced before, it’s deeply moving to witness their sense of wonder. Just as I was inspired by Professor Tada, I now hope to leave a positive impact on the next generation.
Tropical Medicine Is Romance
Kitamura:
What do you think is the significance of Japanese contributions to tropical medicine?
Moriyasu:
There’s academic and practical value, of course, but above all, there’s “romance.” When I hear the sound of waves by a beach with palm trees or feel the wind off Lake Victoria, the song “The Lion Standing in the Wind” starts playing in my head. The idea that someone in Kenya and I are both alive on this planet, at the same time, is miraculous in itself. Even more so that we are working together to fight the same disease—it’s nothing short of a miracle. Just the fact that we stand together against infectious diseases, humanity’s common enemy, fills me with a sense of romance.
Kitamura:
“Tropical medicine is romance”—what a beautiful expression. Do you have any advice for the students in the Japanese Society of Tropical Medicine’s student division?
Moriyasu:
It might feel a little embarrassing or naive, but I encourage everyone to speak about their own sense of romance. When I joined the Tropical Medicine Research Society at Kyushu University, I found that, without any prior arrangement, people with the same aspirations naturally gravitated toward each other. That encounter changed the course of my life. I hope students today can experience that same kind of dynamism.
The friends I met back then are now people I can work with, even after 10 or 20 years. We sometimes talk about collaborating on projects together again. The connections you form in your youth are truly valuable. Tropical medicine lets you grow into adulthood while keeping your dreams alive.
And when you travel to places like Africa, there’s so much to learn. You don’t have to do research—even just going to a new place, eating unfamiliar foods, or speaking with someone you’ve never met before is amazing. The experiences you gain through the student division of the Japanese Society of Tropical Medicine are incredibly valuable. Even if you don’t continue with tropical medicine after graduation, the things you learn will undoubtedly support you no matter what field you pursue in the future.
From left, Yuma Yasunaka, Dr. Taeko Moriyasu, and Aika Kitamura
Profile of Interview Participants
Taeko Moriyasu
Assistant Professor, Global Collaboration Division, Nagasaki University.
After obtaining her clinical laboratory technologist certification from the School of Allied Health Sciences at Kyushu University, she worked at the Japanese Red Cross Nagasaki Atomic Bomb Hospital. While working, she earned a bachelor’s degree in economics and later a master’s degree in economics from Nagasaki University. Following a 10-year career break for marriage and childbirth, she obtained her Ph.D. in medicine in the field of parasitology at Nagasaki University. Drawing on her multidisciplinary background, she contributes to various international projects. Her hobbies include growing houseplants.
Aika Kitamura
Graduated from the School of Life Sciences, Faculty of Medicine, Tottori University in March 2025.
First-year master’s student at the Graduate School of Tropical Medicine and Global Health, Nagasaki University (from October 2025).
She aspires to contribute to the fight against neglected tropical diseases (NTDs) through basic research and aims to conduct research that directly addresses local needs in the field. Her research interests include schistosomiasis, basic research, and molecular epidemiology. Her favorite pastime is traveling abroad.
