He took a deep breath to try to calm down.

This virus is highly infectious.

My computer was infected with a virus.

This container is a keepsake from my grandmother.

The environmental issues are becoming more serious.

Environmental issues are becoming more serious day by day.

He is an expert in virology.

My computer got infected with a computer virus.

The Ebola virus is a very infectious virus.

The poliovirus is a virus that primarily enters the body through the mouth and destroys the nervous system.