Virology

Virology is the branch of science that studies viruses and virus-like particles, focusing on their structure, genetics, replication, evolution, and interactions with host organisms. Viruses are obligate intracellular parasites, meaning they require a host cell to replicate. They have diverse genome types, including single- and double-stranded DNA and RNA, and can infect all domains of life, from bacteria to plants and animals. Virology also encompasses virus ecology, transmission dynamics, and virus-host coevolution, as well as the use of viruses as tools in research, therapy, and biotechnology.

Historically, the study of viruses began in the late 19th century with the discovery of tobacco mosaic virus by Dmitri Ivanovsky and the subsequent work by Martinus Beijerinck, who coined the term virus. Advances in imaging, biochemistry, and molecular biology led to insights into viral structure, replication cycles, and taxonomy. The Baltimore classification groups viruses by genome type and replication strategy; the International Committee on Taxonomy of Viruses maintains formal taxonomy.

Virology employs methods such as cell culture, electron microscopy, nucleic acid amplification and sequencing, serology, and computational analysis to detect and characterize viruses. Applications include vaccines, antiviral drugs, diagnostic tests, and gene therapy vectors. Bacteriophages are studied both as models and potential therapeutic agents; plant and animal viruses impact agriculture and medicine.

Public health virology concerns outbreak surveillance, epidemiology, and vaccination programs. Biosafety and biosecurity guidelines govern laboratory work with pathogenic viruses, reflecting the need to balance scientific advancement with potential risks and ethical considerations.