Cytological Diagnosis of Infectious Diseases: Identification of Pathogens and Recognition of Cellular Reactions

Cytological diagnosis of infectious diseases is as important as the cytodiagnosis of malignancies, because the detection of pathogens in cytological specimens is crucially valuable for prompt and appropriate patients’ treatment. When compared with histological diagnosis, cytology is strong at detecting microbes under Papanicolaou and Giemsa stains. Host response against the infectious agent can be estimated by the type of background inflammatory cells. Patterns of the inflammatory cellular responses against extracellular and intracellular pathogens should be recognized. Immunocytochemical and molecular approaches can be applied, even when we have only one cytology specimen in hand. The cell transfer technique is useful to create plural material from one glass slide for immunocytochemistry and other techniques. In case of transmissible disorders including sexually transmitted diseases, the prompt and appropriate diagnosis will avoid avoidable transmission of infectious agents among people, and eventually contribute to the safety of the human society.