As viruses evolve and new types emerge, so our perceptions continuously change about their potential for hatching plagues. What can and should be done? Since publication of this book in 1998, we now have to face the possible return of smallpox and its use as a weapon of bio-terrorism ( 1). We have witnessed the return of yellow fever to the United States, the first case in seventy-four years. The vector that spreads that disease, the Aedes aegypti mosquito, now dwells in our midst. Even as the march to eradicate poliomyelitis from our world continues at an impressive pace, containment of measles has encountered bumps and setbacks along the way. Measles viruses now infect humans in the tens of thousands in Brazil and in the hundreds of thousands in Japan. The return of measles epidemics highlights its near universal infectivity (>99%) for susceptible populations, the growing pool of susceptible individuals, and the difficulty in eliminating the virus. Since immunization, paralytic poliomyelitis has disappeared from the Americas. Correspondingly, since 1991, the world's total number of recorded cases has diminished more than 89 percent, from over 35,000 to about 2,000 currently. More than twothirds of children under five years of age, approximately 420 million individuals worldwide, have been vaccinated over the last two years. The hope is that by the year 2002, or by 2005, sufficient immunizations will have blanketed the globe's population to wipe out the poliomyelitis virus.
Yet even now immunization must be required and occur not only in Third World countries but also in the United States. As an example, when Dirk Kempthorne, current governor of Idaho, decided to enhance vaccination of susceptible children, he appointed Jim Hawkins to oversee the program. Because Hawkins was infected with the poliomyelitis virus as a child, he knows its horrors well. Despite this, he is confronted with opposition groups from the Christian Coalition, some other religious factions, and antigovernment groups who do not want any agency or government telling them what to do with their children. As a consequence, the pool of unvaccinated children grows, and the risk to all citizens increases. Currently, Idaho ranks low