Round Table Discussion

Abstract

Chairman Blattner: During recent years, there has been increasing interest shown in diseases caused by filterable viruses, and significant work has been accomplished in this comparatively new and absorbing field of endeavor. With the advent of chemotherapeutic agents and antibiotics, the presence and action of these infectious agents has become more apparent. Viral diseases, therefore, have assumed increasing importance in medical literature in general and in pediatric literature in particular.

By way of review, it is well to bear in mind that viruses are filter-passing agents, obligate intracellular parasites, capable of reproducing themselves and of producing disease in plants and animals, including man. While these agents cannot be seen except by the most elaborate methods, their presence can be detected by their injurious effects.

The pathologic picture produced by viral agents is rather characteristic and can be recognized readily by experienced observers acquainted with tissue response. In some instances, inclusion bodies are produced which may be intranuclear or intracytoplasmic, and represent cytologic changes which are considered typical of the pathologic response to viral invasion. When inclusion bodies are present they may serve as sign posts for the recognition of the type of infectious agent.

The nature of a filterable virus is as yet unknown. Viruses may be a form of life similar to bacteria, but infinitely smaller in size. It is conceivable that viruses are enzymes capable of reproducing themselves and capable of producing cellular response. They may be non-living, crystallizable substances, such as the Stanley tobacco-mosaic virus; or a form of life, the definite nature of which is as yet unrecognized. Dr. Thomas M. Rivers has stated : "Viruses are a heterogeneous collection of diverse agents which happen to induce a state of broad similarity." He points out that the reaction of the tissues in general, and of the cells in particular, determines the nature of the pathologic process about as much as the infectious agent itself.