Viruses

A virus is a small infectious agent that replicates only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and fungi. As the world's smallest living organisms, viruses are a major threat to global public health and can cause a variety of illnesses ranging from the common cold and flu to more serious diseases such as HIV/AIDS, Ebola and Zika. Viruses have also been used in biotechnology and gene therapy to treat diseases and have even been used to produce new vaccines. Through further research and development, viruses are likely to play an increasingly important role in the field of medicine.