Health

The fight against disease is far from over. Dr Hiroshi Nakajima, Director-General, the World Health Organisation, argues that we face a global health crisis unless the international community takes action

Until relatively recently, the long struggle for control over infectious diseases seemed almost over. Smallpox was eradicated and half a dozen other diseases were targeted for eradication or elimination. Vaccines protected about eight out of ten of the world's children against six killer diseases. Antimicrobial drugs were effectively suppressing countless infections. However, in the path of these successes, cautious optimism has been overtaken by a fatal complacency that is costing millions of lives a year. Infectious diseases are the world's leading cause of death, killing at least 17 million people - most of them children - every year. Up to half the 5.72 billion people on earth are at risk of many endemic diseases.

Far from being over, the struggle to control infectious diseases has become increasingly difficult. Diseases that seemed to be subdued, such as tuberculosis and malaria, are fighting back with renewed ferocity. Some, such as cholera and yellow fever, are striking in regions once thought safe from them. Other infections are now so resistant to drugs that they are virtually untreatable. In addition, deadly new diseases such as Ebola haemorrhagic fever, for which there is no cure or vaccine, are emerging in many parts of the world. At the same time, the sinister role of hepatitis viruses and other infectious agents in the development of many types of cancer is becoming increasingly evident.

The result amounts to a global crisis: no country is safe from infectious diseases. The socio-economic development of many countries is being crippled by the burden of these diseases. Much of the progress achieved in recent decades towards improving human health is now at risk.

A global challenge

Poverty exposes hundreds of millions of people to the hazard of infectious diseases in their everyday lives. More than 1 billion people live in extreme poverty. Half of the world's population lacks regular access to the most needed essential drugs.

Continuing global population growth and rapid urbanisation force many millions of city dwellers to live in overcrowded and unhygienic conditions, where lack of clean water and adequate sanitation are breeding grounds for infectious disease.

Migration and mass movements of millions of refugees or displaced people from one country to another as a result of wars, civil turmoil or natural disasters, also contribute to the spread of infectious diseases.

As a result of the economic and social crises still affecting many countries, health systems which should offer protection against disease have, in extreme cases, either collapsed or not even been built. The result is a resurgence of diseases that were once under control or should be controllable, given adequate resources. Disabled by these diseases, some societies are unable to get themselves back on their feet.

Increasing international air travel, trade and tourism result in disease-producing organisms being transported rapidly from one continent to another. Reporting of infectious diseases now poses serious economic threats to trade and tourism. Some countries impose unjustified restrictions on travellers coming from infected countries; others are tempted to conceal information about infections within their own borders. The result is a fragmented, unco-ordinated approach to infectious disease control and inadequate global information to allow worldwide monitoring.

Changes in the global food trade create new opportunities for infections to flourish. They include the shipment of livestock, new methods of food production, storage and marketing and altered eating habits.

The effects of climate change may allow some diseases to spread to new geographical areas. Microbes continue to evolve and adapt to their environment, adding antimicrobial resistance to their evolutionary pathways.

A global response

For all these reasons, controlling infectious diseases is an imperative global challenge that requires a global response. There is an international consensus that priorities have to be set and activities initiated speedily. This favourable environment for action needs to be exploited, and in WHO's view there are three priorities for international action over the next five years.

The first priority is to complete unfinished business, namely the eradication and elimination of diseases such as poliomyelitis, dracunculiosis, leprosy and Chagas disease. This does not require a huge expenditure, and if the resources are not found, these diseases will return with a vengeance and previous efforts will be lost.

The second priority is to tackle old diseases such as tuberculosis and malaria which present new problems of drug and insecticide resistance. Here there is a need to remove infectious sources in the community and cure a high proportion of infectious cases, establish appropriate national and international epidemiological surveillance and undertake research on treatment regimens and improved diagnostics, drugs and vaccines. Work is needed on developing new and improved vaccines against neonatal tetanus, bacterial meningitis, tuberculosis and other diseases.

The third priority is to take short-term and long-term action to combat newly emerging diseases. A speedy response is needed to outbreaks of important new infections, wherever they occur. At the same time there is a need for intensive research on the natural history of new diseases and on possibilities for preventing, treating and controlling them. A global surveillance programme is also essential.

The world has lost sight of its priority to reduce poverty through better health and foster development by fighting disease. Today, infectious diseases are not only a health issue; they have become a social problem with tremendous consequences for the well-being of the individual and the world we live in. We need to recognise them as a common threat that has been ignored, at great cost, for too long, and to build the global solidarity to confront them. What is required is the commitment of the international community to helping countries most at risk to help themselves. By helping each other, nations united protect the world and protect themselves.