(b) Child medical research in one form or another has led to the virtual elimination in industrialized countries of the leading causes of child mortality and morbidity, including tetanus, pertussis, diphtheria, poliomyelitis and measles. Though not yet sufficiently implemented, a simple and effective treatment has been found for diarrhoea (the main cause of child death in developing countries), and progress is being made in treating certain forms of cancer, which is among the largest child killers in the industrialized world.