Economic Importance of Viruses Viruses are acellular infectious agents composed mainly of nucleic acid (DNA or RNA) surrounded by a protein coat called a capsid. They can infect plants, animals, and microorganisms. Although many viruses are harmful and cause diseases, they also have significant economic importance in medicine, agriculture, biotechnology, and scientific research. Harmful Effects of Viruses Viruses cause several diseases in humans, animals, and plants, resulting in major economic losses. Viral diseases affect human health, reduce agricultural production, and cause damage to livestock industries. Importance in Human Diseases Many viruses cause serious diseases in humans. Examples include influenza virus causing flu, human immunodeficiency virus (HIV) causing AIDS, hepatitis viruses causing liver diseases, and coronavirus causing respiratory infections. These diseases lead to healthcare expenses, loss of productivity, and economic burden. Importance in ...