What is a virus? Even experienced microbiologists need to stop and think before answering this simple question. Viruses are tiny. The SARS-CoV-2 coronavirus has a width of no more than one hundred nanometers. Ten thousand such viruses lined up after each other will barely have the width of a pinhead. But an invisible enemy like this can bring a whole world to its knees, just as it did in spring 2020, with the COVID-19 pandemic. Through carefully selected stories, the author shows you what a virus is, what it consists of, how it is transmitted and how it produces disease.

Viruses and humans have coexisted forever, so this journey covers biological evolution, our own bodies, historical events, diagnostics, global politics, genetic material, ethics and biological warfare. The book is also about vaccines, one of our most important weapons in the war against viruses. The making of vaccines is in itself a science which is based upon our knowledge of how viruses are constructed and cause disease.

Viruses are bred to spread and don’t hesitate to set off on intercontinental journeys, like the travel-loving stowaways they are. In this book, you’ll get to know different kinds of viruses: some of the most common, some that are extremely cunning and some that are so dangerous their fatality rate is close to 100%. Viruses cause contagion by travelling, just as we do, but their journey doesn’t stop there. The way in which they produce disease inside us can also be viewed as a microscopic travelogue. We shall therefore follow some viruses as they travel through our bodies to reach the cells they both hijack and harm.

If you are prepared to face what fear of viruses you might have, you’ll discover that knowledge of viruses is extremely helpful. In certain situations, it may help you survive and avoid diseases like warts, cold sores, shingles, blindness and even cancer.