Cytological diagnosis of virus-infected cells in Papanicolaou smears and its application in clinical practice.

The cytopathic changes of herpes simplex virus, varicella-zoster virus, the human polyomaviruses, and the trachoma agent can be recognised in smears prepared from a wide variety of specimens. The morphology of virus-infected cells is described, and the clinical value of these observations is discussed. Cytological diagnosis offers a rapid and convenient method of detecting infection with these viruses which can be confirmed by conventional virological method while the patient is still in the acute stages of the disease. Confirmation can also be made retrospectively by reprocessing cells, identified in the Papanicolaou smear, for electron microscopy. Screening for virus-infected cells in cytological smears is a technique that can be developed in any pathology laboratory prepared to provide a comprehensive cytology service, and it is proving to be a useful tool in clinical diagnosis and applied research.