Viral pathogens are infectious agents that cause various diseases in humans, animals, and plants. These pathogens are composed of a nucleic acid genome (either RNA or DNA) surrounded by a protein coat called a capsid. Some viruses also have additional layers, such as an envelope derived from the host cell membrane. Viruses can infect host cells by binding to specific receptors on the cell surface and injecting their genetic material into the cell. Once inside the cell, the virus replicates and produces more virus particles, eventually leading to the destruction of the host cell and the spread of the infection to other cells in the body. Research on viral pathogens aims to understand the molecular mechanisms of viral infection, replication, and transmission, as well as to develop strategies for prevention, diagnosis, and treatment of viral diseases. This research area is of critical importance for public health, as viral pathogens are responsible for a wide range of diseases, including influenza, HIV/AIDS, COVID-19, and hepatitis.