Population Dynamics of Rabies in Wildlife

Preface Rabies has been known and feared as a killer disease for over 2000 years. Its association with `mad dogs' has also been understood since then, although it was not until the early nineteenth century that it was shown that the disease was passed from one animal to another and did not arise, spontaneously, during inclement weather. By the end of the nineteenth century a vaccine had been developed, but it often had serious side effects and was painful to receive. During the last few decades great strides have been made in vaccine development so that, in the developed nations, the disease has lost much of its aura. However, its associations with the stigma of madness (the faithful pet that turns on its owner), the horrifying symptoms in man and the inevitability of death once symptoms appear maintain the awesome image of the disease. In developing countries the disease is still a very serious problem. It is estimated to cause at least 15,000 human deaths annually, and the economic losses of cattle in Latin America alone cost around U.S. $250,000,000 directly and U.S. $250,000,000,000 indirectly a year. In the poorer developing nations, the lack of diagnosis and high costs of the effective vaccines prevent treatment in man, whereas, in the richer nations, vaccination of domestic animals, especially dogs, cats and livestock, has reduced the disease to a minor problem, predominantly in wild animals. Even so, the fear of rabies is so great that about 99% of all 'postexposure' treatments are probably unnecessary, and this, plus the losses of cattle (or cost of immunising them), makes the disease expensive even to developed countries. During the last hundred years or so the role that wildlife plays in rabies outbreaks has become clear, and the qualitative observations indicating that the disease did not spread in areas where its wild hosts were rare led to the expectation that killing the hosts would eliminate the disease....