Hisae Kasai

Infection in Fish

Hisae Kasai , Associate Professor

Faculty of Fisheries Sciences / Graduate School of Fisheries Sciences (School of Fisheries Sciences, Department of Aquaculture Life Science)

High school : Hokkaido Prefectural Kushiro Konan High School

Academic background : Doctorate at Hokkaido University

Research areas
Research keywords
fish disease, viruses, vaccines

What are you aiming to achieve?

I am engaged in research into disease in fish in order to prevent outbreaks of fish diseases. Just like humans and animals, fish catch disease. Microorganisms (pathogens) that cause disease in fish include many kind of viruses that result in high death rates, and control strategies against these are urgently needed.

In order to prevent disease in fish, it is important to select the parent fish. We are aiming to establish a blood testing method that has similar standards to those used in humans and animals. At the same time, if the water in which the fish are reared is contaminated with pathogens, then it becomes difficult to prevent the outbreaks of disease even if healthy fry are introduced. Furthermore, if wastewater containing pathogens is released from a facility where infection has occurred into rivers or coastal areas, then downstream or coastal marine areas can be contaminated across a wide area, causing an epidemic of the disease. I researched the sterilization of breeding water and wastewater during my doctorate course, and established a method which is capable of disinfecting around 100 tons of seawater per hour. At present, its use is being rolled out in public sector cultivation centers (facilities that produce fry for release).

Photo 1 Experimentation

Photo 2 The laboratory team – photo taken with a visiting researcher from Thailand


What sort of equipment do you use to perform what type of experiments?

We need to culture cells that perform the role of host in order to then cultivate viruses. In order to prevent microorganisms present in the air from contaminating the culture, and also to maintain the safety of those working on the experiment, we use a device called a “safety cabinet”. There have to date been no cases of fish viruses infecting mammals, but since we sometimes work with unknown pathogens, we have to be extremely careful to maintain and prepare the environment in which we do our experiments.