pathogenic viruses (those that cause disease in humans) have caused more deaths on this planet than all of the wars famines and natural disasters put together. every year just the flu virus causes tens of thousand of deaths in the united states alone. in 1918 that number was in the millions from the spanish flu epidemic. certain viruses cause pneumonia. and meningitis. and yes even the common cold. just a cold can cause harm. some viruses cause diseases in plants/crops and other animals. viruses destroy living tissue destroy bodies destroy ecosystems and economies. they most definitely cause harm in so many different ways.
how can viruses cause harm?