Charting the future
　　By the end of the 20th century we could be living in a world without poliomyelitis, a world without new cases of leprosy, a world without deaths from neonatal tetanus and measles, a world without dracunculiasis. In 1993 measles killed nearly 1.2 million children and infected more than 45 million; poliomyelitis killed 5 500