January 9, 2004 - With the flu season upon us, Canadians are naturally concerned about getting sick. We're washing our hands more often, getting flu shots and generally trying to keep healthy. But for millions of people in developing nations, battling communicable and chronic diseases is a daily fact of life.
World disease patterns are shifting. For years it was assumed that industrialized society would suffer less from infectious diseases as they were eliminated with modern medicines, and more from chronic disease as the population ages.
However, the recent emergence of new infectious diseases (37 new disease-causing organisms have been discovered since 1973) and return of older ones shows that the situation is decidedly more complex. As every flu season tells us, developed nations are far from immune to communicable disease. And chronic diseases such as diabetes are indeed developing into an epidemic. One billion people worldwide are overweight and 300 million are clinically obese, making them five to 10 times more likely to suffer from diabetes.
The situation in developing world is even more complex. By now, most people know about the horror of AIDS in Africa and the effect the disease is having on millions of families and entire countries there. It's a problem that will continue to echo through the continent for generations. But there are plenty of other diseases infecting people in developing countries, from tuberculosis to malaria, some of which you rarely hear about, even though they affect millions.
Soil-transmitted parasitic helminthes (a type of nematode worm), for example, don't exactly get much press, but they certainly cause enough sickness to be considered one of the great scourges of the third world. These parasites, such as roundworm, hookworm and whipworm, are found in the soil in some areas and spread through ingestion of infected soil or through the soles of bare feet. Once in the human body, they spread to the lungs, the mouth and eventually the intestines, where they attach themselves and suck blood.
Worms are expelled through feces, so contact with feces-contaminated soil is the main cause of transmission. Children are at high risk because they are often barefoot, but also because resulting blood loss to the parasites can lead to anemia and protein deficiency, which can stunt growth and cause developmental defects.
According to a recent report published in the journal
Science, about 25 per cent of the world's population is infected with roundworm, 20 per cent with hookworm, 17 per cent with whipworm and up to four per cent with schistosomiasis. A full one third of the planet suffers from at least one of these parasites. Together, they account for 43.5 million life-years lost, second only to tuberculosis.
Symptoms of these parasites range from loss of appetite to nausea, vomiting, fever and weakness. Left unattended, they can have serious health implications - from malnutrition and chronic intestinal inflammation to impaired growth and development. Pregnant women suffer greatly because their bodies require extra nutrition, which is stolen away by the parasites. Helminthe parasites can lead to low birth weights and a greater likelihood of infection for the child - creating a vicious cycle of entrapment
Although intestinal parasites have largely been eliminated from developed countries, the overall incidence of infection has remained about the same for the past 50 years. In other words, little has been done to control the problem in the developing world. It's estimated that at least one billion people will need regular treatment to start reducing the number of people infected with roundworm alone.
It can be done. A systematic campaign to reduce guinea worm, for example, has proven successful, with the number of cases falling from 3.2million in 1986 to just 64,000 in 2001. It's a matter of industrialized countries finding the will to fund the necessary programs to bring the successes of parasite eradication to the world's poorest countries.
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