Perhaps even more important in the long term are developments that can benefit whole communities rather than individuals. Genetic screening techniques provide rapid, precise ways to analyze foods for contamination by pathogens and determine the cause of incipient epidemics. Environmental issues such as the purification of contaminated land and water supplies are also being addressed. The availability of sufficient, safe food in places where it is needed is a continuing challenge. Plants genetics is beginning to address this important problem by developing plants for increased agricultural productivity, especially in relatively infertile areas including those where fresh water is limiting.
Green plants are the one efficient and renewable way to use directly the sun's energy.
These approaches could decrease dependence on fossil fuels and the pollution they cause. They can also permit conservation of land in a natural state hospitable to other animals and plants. People worldwide will want to take advantage of these benefits. To do so will require thoughtful discussion of the related personal, social, and ecological questions they raise and the development of scientifically sound approaches to their use and regulation. Although vaccination has been demonstrated as the most effective way to prevent infectious diseases, its major public health impact has been restricted to the control of a limited number of human diseases including smallpox, poliomyelitis, neonatal tetanus, diphtheria, pertussis, or measles.