vol.17 Department of Hygiene

Professor Hiroshi Nishiura, a chair of the Department of Hygiene since 2016, says: “The frequency of emerging infectious diseases, such as Ebola, Zika and Middle East respiratory syndrome (MERS), is said to be increasing over the past half century. This is partly attributable to the growing mobility of people by air travel and increasing opportunities for them to contact animals in the natural settings. It is possible that a largely unknown infectious disease immediately appears in humans in a remote corner of the world and rapidly spread around the globe, forcing state and local governments to come up with sensible countermeasures to control it.

Professor Nishiura is an expert in real-time studies that quantify the transmission potential of emerging infectious diseases that are prevalent in some parts of the world, and also the probability of death from those diseases for the sake of appropriate risk assessment. The Department of Hygiene has established a research team in social medicine whose members use mathematical models for the analysis of infectious diseases and demographics.

The team at the Department consists of people with diverse backgrounds and includes physicians, public health nurses, and Japanese and international graduate students and postdoctoral researchers in the fields of mathematical sciences, biology, physics, veterinary medicine, statistics, informatics and policy science, as well as researchers from Hokkaido University and beyond. “The Department is a mixture of researchers with various backgrounds is a source of pride for us. We come to enjoy our differences in language and in the way of looking at things as we continue discussions on our common themes.”

Except during the epidemic of an emerging infectious disease, members of the Department are engaged in their respective studies on vaccine-preventable diseases, including rubella and measles, other infectious diseases and demography.

In November 2017, under the guidance of Professor Nishiura, a postdoctoral fellow at the Department conducted an epidemiological study on infectious disease risks among defectors from North Korea. They analyzed epidemiological data obtained from non-governmental organizations helping North Korean defectors resettle in Canada and South Korea. The study found a substantial risk of measles and tuberculosis among children, as well as the presence of a certain number of subjects with diseases such as vivax malaria, which is prevalent near the border with South Korea. This epidemiological study was followed immediately by a surge in the number of wooden boats from North Korea that were found on and off the Sea of Japan coast. Since the crew of those boats included people with active tuberculosis, there were concerns about the health of governmental officials in Japan who were exposed to the disease during the duty. In this way, the Department is seeing its role expanded as the Japanese government works to hurriedly come up with measures to deal with refugees.

“Vaccinations are an essential part of the government’s infectious disease control policy. We will be able to lay out the direction of the most effective and efficient vaccination strategies if the epidemic dynamics of infectious diseases can be elucidated using mathematical modeling together with demographic data and data on human contact patterns relevant to the spread of infectious diseases, rather than blindly giving vaccinations. To prevent the spread of rubella, for example, it is necessary to present model-based data and estimates supported by theory, such as about age, gender and other factors of vaccine administration.”

At this highly international Department, English is used as the official language for seminars, workshops and research consultations. Professor Nishiura encourages graduate students, including those who are not fluent in English, saying: “Even if they’re not good at English at the moment, they will be fine if they take the opportunity in our department to improve their English communication and writing skills and actively try to communicate with members.” He helps students boost their research credentials to apply for the Japan Society for the Promotion of Science (JSPS) Fellowship, which gives Japanese scientists an opportunity to carry out research at an overseas first-rate research institute. He works to guarantee a bright future for his students by encouraging them to build their experience in writing papers strategically from the moment they join the Department.

On the other hand, he stresses the needs for students who aspire to become educational researchers in a depopulating society to outperform other students in terms of research achievements while at graduate school. “This research field is vulnerable to the changes of the times. They write down every detail of their work in every single equation today, but that will be all taken over by machines someday, and more will be required of them,” he says.

Professor Nishiura advises on the importance of working to develop a field of one’s interest rather than being fixated on infectious diseases, citing an example of an ex-student of his who established a mathematical model for obesity based on a novel idea that “obesity is contagious” and remains at the forefront of obesity studies in the US.