Page 273 - The Veterinary Laboratory and Field Manual 3rd Edition

242 Susan C. Cork and Roy Halliwell

to provide a confirmatory diagnosis. The sam- Laboratory methods used to diagnose
ples required for laboratory confirmation of a viral infections
presumptive diagnosis depends on the type of
the laboratory assay. For example, diagnosis Knowledge of the morphology and genetics of
based on virus isolation requires sterile samples viruses has increased significantly as new tools
maintained in ice or dry ice to prevent bacte- and techniques to study them have developed.
rial contamination whereas for assays based on This has also resulted in re-classification and
detection of viral nucleic acid or antigens, the re-naming of some viruses.
samples may not be required to be sterile. It is Figure 4.17 summarizes a few standard meth-
important to contact your regional or reference ods used to isolate and identify some viruses
laboratory for instructions on collecting suit- of veterinary importance. This information is
able samples and maintaining samples during given to enable technical and extension staff to
shipping. appreciate what is involved in virological exami-
nation although most district or even regional
veterinary laboratories will not usually have

Figure 4.17 Identification and isolation of viruses from clinical samples.

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