Viruses have an enormous influence in our lives.-- daily and historically. The influenza epidemic of 1918 cost far more casualties than World War I, and we still dread the renewed coming of the flu each winter, despite partial potential vaccine protection. The world-wide AIDS epidemic is decimating parts of Africa and Asia, having an enormous effect on many aspects of life in our world as well, and taxing all that we know about medical care - despite the fact that HIV is a relatively weak virus. The efforts to deal with Foot and Mouth Disease are devastating the livestock industry and economy of Britain and beyond, despite all containment strategies. In a format of lectures, seminar discussions, videos and presentations of student projects, we will explore viral infection in terms of molecular biology, ecology, and physiological and historical consequences. We will begin by looking at well-understood infection processes for a very special group of viruses that only infect bacterial cells. These bacteriophages were used to lay the foundations of molecular biology - from the demonstration that DNA is the genetic material to the discovery of messenger RNA to vectors for gene expression. They also play key roles in the natural control of bacterial populations; at any given time, ¼ of the over 1030 bacteria in the oceans are infected by phages, which make them release their rich nutrients high in the ocean, to be used by other organisms, rather than sinking to be mired in the muck as they die. Insects also have their own viruses, which are important in helping control their natural population cycles. In turn, human impact and climate changes lead to new virus patterns, acute and chronic - Hantavirus, Ebola, influenza, herpes, HIV. We will next explore the components of the immune system and the intercommunications between them and between the immune, hormonal and nervous systems, taking advantage of what we have learned from AIDS and other viral infections and from modern technology. We will consider the concept of the immune system as a sixth sense organ and the implications of psychoneuroimmunology, particularly as related to viral infection. We will explore the apparent roles of viral infections and resulting autoimmune responses in such diseases as juvenile-onset diabetes and chronic fatigue syndrome and consider evidence that viral infection actually has a broad stimulatory effect on certain aspects of the system. Viral infections and the resultant cellular responses also play key roles in certain kinds of cancers and have contributed to our understanding of the basic mechanisms of cancer development from all causes. We will focus here on human papiloma virus and cervical cancer and on hepatitis viruses and cancer of the liver and talk about tumor suppressors, protooncogenes, and the importance of apoptosis, or programmed cell death. Worldwide vaccination against major childhood diseases is a major current goal, with the potential to save lives and suffering, as shown by the eradication of smallpox. However, questions are also being raised about potential negative impacts of vaccination. We will explore questions that should be considered before making any personal or public-policy vaccination decision related to the efficacy of particular available vaccines, the timing and routes of administration, the consequences of the illness and potential long-term implications. This upper-division/graduate program is intended both for those with a strong background in biological sciences and those with a more limited background but a strong interest in the subject. As readings, we will be using articles from the scientific and more popular literature, the Encyclopedia of Virology, Scientific American and books like The Coming Plague. Generally, there will be some choices of readings, which will help accommodate differences in background and specific interests. Evaluation will depend on class participation and preparation as well as on a project and class presentation. There is the potential for parallel lab work through an introductory phage course within the Undergraduate Research Program.