Published online by Cambridge University Press: 07 December 2009
Detection of viruses in a patient's secretions or tissue provides direct evidence of current or ongoing infection (Table 48.1). This can be by:
virus culture (also referred to as cell or tissue culture)
electron microscopy – visualization of whole virus particles
detection of viral antigens
detection of viral genome (RNA or DNA) by molecular techniques.
This chapter will discuss the first three techniques; molecular diagnosis is discussed inChapter 49.
Virus or cell culture
Viruses, like bacteria, can be cultured in the laboratory. However, viruses are fastidious intracellular organisms and therefore living cells are required to grow viruses in the laboratory. Many cell lines have been developed to support the growth of different viruses. A single type of cell line is not adequate, as specific viruses need specific receptors on the cell surface to which they attach to gain entry into the cell and to initiate replication. The presence of specific cell receptors on the cell surface determines which viruses will be able to infect them, and this is called ‘viral cell tropism’. For this reason many cell lines have to be maintained in a diagnostic laboratory. Another problem in the laboratory is to maintain these living cells in culture long enough to allow sufficient virus growth.
A suspension of cells in growth medium (consists of a buffer plus calf serum to provide protein and amino acids, and antibiotics to prevent bacterial overgrowth) is put in glass or plastic tubes/flasks, the cells attach to the sides of the container and grow until they become confluent.
To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.