ABSTRACT
Major Causes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262 Specific Invasive and Emerging Wildlife Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
West Nile Virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263 Hantavirus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265 Lyme Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265 Monkeypox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 Raccoon Rabies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Foreign Wildlife Diseases That Could Invade the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268 Highly Pathogenic Avian Influenza . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268 Rift Valley Fever . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270 Nipah Virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 Japanese Encephalitis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
Prevention, Detection, and Control of Invading and Emerging Diseases . . . . . . . . . . . . . . . . . . . . . . . . 272 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274
Following a period of success in controlling infectious diseases with new vaccines, global vaccination programs (smallpox and polio), antibiotics, and advanced treatments, especially in the United States during the 1960s to the early 1980s, an era of invading, emerging, and reemerging diseases began. These diseases accelerated through the 1990s and early 2000s, resulting in new disease threats and outbreaks with increased human health risks and huge economic impacts [e.g., AIDS, Lyme disease (LD), West Nile (WN) virus, and severe acute respiratory syndrome-associated coronavirus (SARS-CoV)]. Of the 175 new human emerging diseases, 75% were caused by zoonotic disease agents transmitted between wild or domestic animals and humans (Cleaveland et al. 2001), and these emerging pathogens were predominantly viruses (Woolhouse and Gowtage-Sequeria 2005); for example, Hantavirus, WN virus, Monkeypox, SARS-CoV, and Nipah virus. Many of the newly emerging pathogens have seriously impacted the global public health and animal health infectious disease infrastructure, and some pathogens had the threat of producing pandemics, such as SARSCoV and recently highly pathogenic avian influenza (HPAI) virus (Fauci et al. 2005). The causes and methods of dissemination of these invading and emerging diseases are as varied as the diseases themselves. Despite advances in medicine and technology, we have been unable to prevent their introduction, establishment, or spread. Recent developments in rapid detection and identification
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capabilities (Kuiken et al. 2003), but many of these diseases have wildlife as natural hosts and disseminators of the pathogens, and we have insufficient resources to effectively manage the diseases in wildlife populations. I discuss some of the major causes of invasive and emerging diseases and provide examples of wildlife diseases of public health and animal health importance that invaded or emerged in North America during the past few decades and some foreign animal diseases that threaten new invasions. I then discuss measures that are in place and those that could be improved to prevent, detect, and hopefully control these disease threats.
The causes of the emergence, reemergence, and invasion of infectious diseases are varied and complex. Factors that are associated with and have contributed to emergence of pathogens include evolutionary changes in the pathogen (HPAI), changes in ecology of the host and pathogens (LD), and invasion of pathogens by movement of the infected host or vector species (WN virus) (Morse 1995; Wilson 1995; Lederberg 1998; Daszak et al. 2000; Cleaveland et al. 2001; Antia et al. 2003; Slingenbergh et al. 2004; Fauci et al. 2005; Gibbs 2005; Woolhouse and Gowtage-Sequeueria 2005). The frequency of new disease threats is increasing while the investment in public health and animal health infrastructure to deal with these challenges tries to keep up in the developed countries like the United States, but falls behind throughout the rest of the world.
