Viral Pathogenesis

Pathogens are disease-causing agents and pathogenesis is the study of the disease process. In cultured cells, observed changes (i.e., death, altered morphology, transformation) can be ascribed directly to virus infection. However disease is a more complex process that may result from direct virus effects, immune responses to infection, or a combination of both. Modern studies of viral pathogenesis seek to understand not only the damage to an organism but the underlying molecular events that cause the observed damage. Diseases caused by human viruses are often studied in animal models. Developing such models may include adaption of a human virus to growth in animals. Or human viruses may be used to inoculate animals by unnatural routes, or at very high doses. Alternatively, studying the pathogenesis of an animal virus in its natural host may provide insight into pathogenesis of a related human virus. Development of model systems can be difficult and expensive but modern genetic methods are providing new avenues of study. Often results from several different models are combined to gain an understanding of the pathogenesis of a single virus.