How can I apply acedemic summer internship?

I want to apply academic internship about my interests and It is necessary to have summer internship in my university after 3rd year. After getting my BS degree I am considering to apply master programs of universities or institutes in  US, Canada and Europe especially Norway and Sweden .That's why I want to apply academic internship in one of these countries. As a junior student I am interested in biochemistry, microbiology, immunology and viruses. Although I didn't take any courses about viruses, I am very very interest in viruses. So, is there anyone having knowledge about academic summer internships and give me some piece of information about it? How can I initiate it and what should I do?