Virology is the branch of microbiology that studies viruses and similar infectious agents, focusing on their structure, classification, genetics, replication, and interactions with host organisms.
Scope, methods and concepts of virology
Virologists investigate viruses that infect bacteria, plants, animals and humans, examining the molecular composition of virions, the organization of viral genomes and the mechanisms by which viruses enter, replicate and exit host cells. Classification schemes such as the International Committee on Taxonomy of Viruses and the Baltimore classification organize viruses based on genome type and replication strategy. Virology encompasses laboratory methods including cell culture for propagating viruses, plaque assays and tissue culture infectious dose assays for quantifying infectivity, electron microscopy and cryo-EM for visualising virion architecture, and molecular techniques such as PCR and next-generation sequencing for analysing viral genomes. Studies of viral replication cycles reveal common stages—attachment, penetration, uncoating, synthesis, assembly and release—and highlight differences among RNA and DNA viruses. Virology also explores latency, integration and recombination in persistent infections, and the coevolution of viruses with their hosts. Understanding host immune responses and viral evasion strategies is critical for developing vaccines and antivirals.
Examples and importance of virological research
Research on influenza viruses has elucidated antigenic drift and shift, enabling the annual formulation of influenza vaccines. The discovery of reverse transcriptase in retroviruses led to the development of antiretroviral drugs and provided tools for molecular biology. Studies of human immunodeficiency virus (HIV) revealed mechanisms of immune cell depletion and informed public health interventions. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019, and virological analyses of its genome and replication rapidly guided diagnostics, vaccine design and antiviral development. Virologists have characterised bacteriophages and used them as cloning vectors and potential alternatives to antibiotics. Work on plant viruses has improved crop resilience by enabling virus-resistant plants. Continued surveillance and research into emerging viruses such as Ebola, Zika and Nipah are essential for early detection and control of outbreaks.
Virology provides insights into fundamental biological processes and contributes to medicine, agriculture and biotechnology by informing strategies to prevent, diagnose and treat viral diseases.
Related Terms: Virus, Virion, Viral genome, Host range, Antiviral