Viral zoonoses - a threat under control?

Despite intensive research and considerable effort to eradicate infectious diseases, modern medicine has failed to control many infectious diseases which have been thought to be easy to overcome with advances in medical science and technology. In fact, infectious diseases remain a dominant feature in public health considerations for the 21st century. Some infectious agents already known to be pathogenic have gained increasing importance in recent decades due to changes in disease patterns. Furthermore, many new, previously unknown infectious agents with a high pathogenic potential have been identified. Nearly all of these emergent disease episodes have involved zoonotic or species-jumping infectious agents. The complex interaction of factors like environmental and ecological changes, social factors, decline of health care, human demographics and behaviour influences the emergence of re-emergence of such diseases. Viruses, especially RNA viruses with their ability to adapt quickly to changing environmental conditions, are among the most prominent examples of emerging pathogens. In this review, we present the important examples of zoonotic viruses and discuss the factors playing a key role in the emergence and resurgence of these diseases. Copyright 2003 S. Karger AG, Basel