Preparing for Global Infectious Diseases

In March 2020, just three months after the novel coronavirus COVID-19 began to make headlines, the infection had spread to 113 countries and regions worldwide, with over 120,000 confirmed cases. The WHO (World Health Organization) declared a pandemic, signifying a global outbreak. Speaking of global outbreaks, many may recall the 2009 novel influenza A (H1N1)pdm09 virus. In April 2009, cases of a new swine-origin influenza virus were confirmed in the United States and Mexico. Two months later, in June, with over 25,000 patients confirmed in about 60 countries and regions, a pandemic was declared.

A characteristic of infectious diseases in modern society is their rapid global spread due to the development of transportation such as airplanes. This has given rise to the concept of global infectious diseases. The novel coronavirus is an ongoing issue, and its spread across the globe remains a volatile situation. Although not causing the same level of turmoil as the novel coronavirus, highly pathogenic avian-origin H5 and H7 subtype novel influenza viruses have emerged, with reported cases of human infection. This means that the threat of new viral infections is lurking around us.

When a new virus emerges, it causes significant human casualties and economic losses. Therefore, crisis management is crucial to prevent the spread of infection. This crisis management can be broadly divided into the following three categories.

Although vaccines are effective for many infectious diseases, a major problem with new viruses is the time it takes to supply them. Therefore, technological development is needed to shorten the time until vaccines can be supplied.

As for therapeutic drugs, antibiotics are used for bacteria, and antiviral drugs are used for viruses. To develop antiviral drugs, the mechanisms of infection have been studied. For example, influenza virus infection is known to involve three processes: (1) entry into the cell through glycan recognition, (2) replication of the viral genome, and (3) budding of virus particles (see figure). Current anti-influenza drugs are inhibitors of processes (2) and (3). However, the emergence of viruses resistant to existing drugs has become a problem. We have been developing peptides that inhibit the cellular entry process (1). Considering the emergence of resistant viruses, it is necessary to develop therapeutic drugs with different mechanisms of action.

The third category, surveillance, requires advancements in technology to monitor for the emergence of new viruses. For diagnosing influenza in hospitals, rapid test kits are widely used. However, improving detection sensitivity to increase diagnostic accuracy remains a challenge, and devices are being developed for higher sensitivity. We are developing a new detection system using medium-sized molecules such as oligosaccharides and peptides that have an affinity for the influenza virus. In particular, we have developed a virus sensor that presents peptides and have succeeded in detecting the virus with high sensitivity using an electrochemical method. We are currently conducting research with the aim of practical application. Using this system, we have also begun developing a detection system for avian influenza viruses to prepare for future pandemics.

As we have experienced with the emergence of the novel coronavirus, the appearance of new viruses has a significant impact on social activities. How humanity will respond in terms of crisis management for global infectious diseases is a major challenge for the future, and great contributions are expected from the field of science and technology.