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"What you need from school are thinking skills, to distinguish evidence from propaganda, possibility from certainty, rational beliefs from superstitions, data from assertions, science from folklore, theory from dogma."
The problems facing the population in the Third World are numerous. Improvements in medical care will only solve a few of these. A large proportion of the local population lives in unhealthy conditions, mostly as a direct consequence of poverty. Lack of income rather than the tropical climate is the leading factor in the occurrence of many diseases. There is a strong correlation between health parameters (life expectancy, child mortality) and economic parameters (GNP, per capita income, income distribution). The fact that health and development are closely related leads to the concept of diseases of poverty. Many of the problems can only get worse if the population continues to increase.
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Why are modern cultures so different from each other? Why is it that until recently Papuans were using neolithic stone tools, while Americans were walking on the Moon? Human history is affected by chance events and as such may seem unpredictable. Over a broader timescale however, there may be repeatable patterns. A fascinating hypothesis is that differences between cultures can arise from very early environmental differences. Some scholars (e.g. Jared Diamond) think that those cultures whose environments contained animals which could be domesticated and wild plants that could usefully be cultivated, developed farming. These cultures grew rapidly. This growth can lead to the establishment of political systems and written language, both aiding general knowledge and the development of new technologies, including weapons. This allowed these cultures to dominate others, as did the germs they brought with them. Some of these germs came from the animals they lived with. They spread easily due to high population densities and absent immunity due to lack of previous exposure. Large sections of the indigenous population of Latin America and the Pacific islands were wiped out when they first came in contact with measles and smallpox brought to them by the Europeans who contacted them.
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Medical disorders, diseases and infections are not isolated phenomena. Public health depends to a large extent on living conditions, social infrastructure, economic development and engineering programmes and to a lesser extent on medical services and medication. Naturally, vaccines, surgery and curative medicines have their place, but sanitary facilities (toilets, sewers, waste water treatment), safe drinking water, a safe and balanced diet, a knowledge of basic medical principles through education, good housing, lifestyle, etc., also have a role that should not be underestimated. As an illustration, reference may be made to the decline of cholera, tuberculosis and leprosy in Europe around the turn of the 19th-20th century, even before the time of antibiotics.
The great majority of diseases in tropical regions are cosmopolitan which means they are found throughout the world: pneumonia, burns, fractures, diarrhoea, asthma, diabetes, hypertension and schizophrenia. Some disorders were also previously found in Europe, but here they have largely disappeared: leprosy, vivax malaria, plague. Only a few diseases occur exclusively in tropical regions, e.g. African sleeping sickness. A number of diseases have disappeared in the West as a result of the improvement of living conditions. The classic, predominantly parasitic tropical diseases are for the most part not the main cause of disease in developing regions, except in certain localised areas where there is a high prevalence. The main medical problems in Third World countries at present continue to be respiratory tract infections, diarrhoea, tuberculosis, malaria, AIDS, measles, accidents, anaemia and pregnancy-related problems. Hepatitis B and C, salpingitis (P.I.D.) and meningococcal meningitis are also frequent problems.
It is important to realise that the distribution and incidence of diseases are constantly evolving. In the past few years there has been a marked reduction in poliomyelitis, river blindness and leprosy. Conversely, there has been a spectacular increase in West African sleeping sickness, dengue, multiresistant P. falciparum malaria and AIDS. Now and again new diseases appear. The risk of epidemics is real. When we think for example of what the so-called "Spanish Flu" caused at the end of the First World War, we must remain cautious and alert.
[Spanish Flu was first observed in March 1918 and in the following year 20-40 million people across the world died from the disease.] The recent appearance of SARS and avian influenza type H5N1 with transmission to humans, reminds us of the dangers.As economies develop, other diseases previously first seen in Western countries will become more common, such as cancer, caries, cardiovascular diseases and multiresistant micro-organisms. Problems typical of large cities will become more important in the near future as urbanisation increases in Third World countries. The poor neighbourhoods and slums of conurbations such as Cairo, Lagos and Kinshasa in Africa, Sao Paulo, Rio, Lima and Bogota in South America, Dhaka, Calcutta, Bombay, Delhi, Karachi and Manila in Asia pose their own problems, but also offer opportunities for improvement.
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In the West, the fear of attacks with biological weapons is increasing. Anthrax, plague, botulism and certainly variola major (smallpox) are high on the agenda. Although smallpox has been eliminated for decades and officially there are only two places where the virulent pox virus is stored (CDC in Atlanta, USA and the State Research Centre of Virology and Biotechnology, Novosibirsk, Russia), the possibility of the deliberate spread of the virus is considered to be real. An attack of this kind could be an unparalleled catastrophe (30% mortality in a non-immune population). For this reason, production of a large stock of vaccine was started in 2001 (Acambis, Cambridge, MA, USA). Vaccination of certain target groups in the USA was resumed.
Some diseases are due to infections, such as tuberculosis, while others are caused by inadequate diet, e.g. beri beri, kwashiorkor, pellagra. Others in turn are genetically determined, such as sickle cell anaemia. There still remain, however, numerous uncertainties and gaps in our knowledge of and insight into many diseases. An understanding of how current concepts have arisen (how we know what we know) is important. We will provide an overview of individual diseases currently associated with tropical regions and areas of extensive poverty.
Some concepts recur constantly and are explained below.
