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Introduction to Viruses

Author(s): Christine Herrmann, PhD

How Are Viruses Studied?

With a few exceptions, viruses are too small (in the range of 10 to 200 nm) to be seen with a light microscope, so virologists use the more powerful electron transmission microscope to study them. The higher resolutions, facilitate identification of the type of virus and its structure. When there is a new outbreak of disease, such as during the 2003 SARS outbreak scientists can examine the unknown agent under an electron microscope and obtain clues about the virus with which they are dealing. Knowing the structure of a virus also is very helpful when designing drugs and vaccines to combat the agent.

Scientists prefer to be able to grow viruses in cell culture (cells derived from another organism and grown in controlled conditions), where it is much easier to study the virus. Some viruses, however, will not grow in cell culture using existing techniques (the techniques may work, but sometimes it takes awhile to find the right cell culture system). To study these viruses, virologists must infect susceptible animals to obtain enough of the agent to conduct their research.

Virologists study the genetics of viruses, how viruses cause disease, and how they interact with components within the host cell and the host’s immune system. Wherever possible, scientists also mutate viral genes to determine their functions in the virus life cycle. Using all these lines of research, virologists work to understand viruses, especially those which cause disease, and to gain information that can be applied to the design of antiviral drugs and vaccines. Particularly when working with potentially deadly viruses, virologists must adhere to strict safety procedures and perform manipulations in laboratories specially designed to contain the viruses. 

Funded by the following grant(s)

Video and transcript courtesy of Wah Chiu, PhD, National Center for Macromolecular Imaging at Baylor College of Medicine. Funding for the video provided by NCMI, NIH.