The preparation process however is time-consuming, laborious and expensive and requires the access to a laboratory which routinely performs this procedure. Advantages of viewing sectioned material Virus may be identified within the lesion which characterizes a particular disease. Site of intracellular viral replication may be observed. This is often useful in identifying the virus family. Immunolabelling with colloidal gold markers is possible when a specific antiserum is available.
Viral morphology is depended on specimen preservation.
Poor fixation or high tissue autolysis may render viruses nondescript or may induce changes in otherwise normal cells which resemble certain viral groups. Some commonly encountered psittacine viruses as seen in both negatively stained preparations and sectioned material are depicted in figures 1 - 16. Adenoviridae Fig 1. Negative stained preparation from liver homogenate. Thin section through nucleus of hepatocyte.