Investigating of the occurrence of pathogenic viruses in drinking water sources and their reduction efficiencies in drinking water treatment processes by applying novel virus quantification and concentration methods
Dr. Nobutaka Shirasaki
Assistant Professor
Division of Environmental Engineering
Faculty of Engineering
Hokkaido University
*The organization and the title are those when awarded
Research summary
To control waterborne diseases and to ensure a stable supply of safe drinking water, it is essential to understand the occurrence of pathogenic viruses in drinking water sources and their removal efficiencies in drinking water treatment processes. Dr. Shirasaki improved and optimized a method that combines a photoreactive intercalating dye, which is used to determine whether bacteria are alive or dead, with a PCR*1 method1 for virus quantification, and developed a novel virus concentration method using two membranes, making it possible to investigate the occurrence of pathogenic viruses and to discuss the presence or absence of infectious viruses in drinking water sources. By applying the developed virus concentration method to water samples collected at actual drinking water treatment plants, he successfully evaluated the virus treatment properties in full-scale drinking water treatment processes. Furthermore, he prepared virus-like particles (VLPs)*2 of human norovirus, which is difficult to culture, and developed a method to quantify them in high sensitivity, and then successfully evaluated the removal efficiencies of human norovirus particles in drinking water treatment processes. This method is more time-efficient compared to the traditional culture method for human norovirus. In addition, he established a method for producing purified solutions of human sapovirus3 at high concentrations, and a method for evaluating its infectivity. As a result, he succeeded in understanding the removal and inactivation efficiencies of human sapovirus*3 in drinking water treatment processes ahead of the rest of the world.
Polymerase chain reaction (PCR) is a technique to amplify specific DNA sequences through the action of an enzyme called heat-resistant DNA polymerase.
Virus-like particles (VLPs) are particles that are equivalent in size, particle structure, and antigenicity to real viruses. It can be prepared large quantities without cell-based culture.
Sapovirus belongs to the same family of Caliciviridae as norovirus. It causes viral gastroenteritis.
Polymerase chain reaction (PCR) is a technique to amplify specific DNA sequences through the action of an enzyme called heat-resistant DNA polymerase.
Virus-like particles (VLPs) are particles that are equivalent in size, particle structure, and antigenicity to real viruses. It can be prepared large quantities without cell-based culture.
Sapovirus belongs to the same family of Caliciviridae as norovirus. It causes viral gastroenteritis.
Introduction to Research
