Epidemiology of Human and Animal Viral Diseases

Murphy, F. A.

Viral disease epidemiology is the study of the determinants, dynamics, and distribution of viral diseases in populations. The risk of infection or disease in a population is determined by characteristics of the virus, the host, and the host population, as well as behavioral, environmental, and ecological factors that affect virus transmission from one host to another. Viral disease epidemiology has come to have a major role in clarifying the etiologic role of particular viruses and viral variants as the cause of specific diseases, in improving our understanding of the overall nature of specific viral diseases, and in determining factors affecting host susceptibility and immunity, in unraveling modes of transmission, in clarifying the interaction of viruses with environmental determinants of disease, in determining the safety, efficacy, and utility of vaccines and antiviral drugs, and especially in alerting and directing disease prevention and control actions. Information on incidence, prevalence, and morbidity and mortality rates contributes directly to the establishment of priorities for prevention and control programs, whether this involves vaccine or drug development and delivery, environmental and hygienic improvements, enhancement of nutritional status, personal or community behavior, agricultural and food processing enhancements, reservoir host and vector control, and international cooperation and communication.