THE AMBASSADORS
THE AMBASSADORS
NEWS
Volume 1,
Issue 3
November 1998
SCHISTOSOMIASIS
THE SILENT
SCOURGE OF DEVELOPMENT
At the dawn of the twentieth
century, to the world's dismay, over 200 million people worldwide
still suffer from schistosomiasis – a parasitic infection
which, if not controlled, can cause the development of liver and
urinary tract disease and cancer of the bladder. Over 20 million
people are chronic sufferers, most of them living in the 48
African countries where the disease is now endemic.
What is most saddening is that controlling this scourge is straightforward but interest in it has waned in recent years. Between December 2 and 4, meetingings were held at the World Health Organizations (WHO's) Geneva headquarters with the attendence of over 50 experts from 22 countries to look at means of increasing international recognition of the schistosomiasis problem and reaching larger numbers of infected people.
"We have an effective drug – praziquantel – which kills all the schistosome species and a course of treatment only costs between 30 and 40 US cents. But the numbers of people affected means that buying sufficient quantities of the drug is beyond what most developing countries can afford," says Dr. Lorenzo Savioli, head of WHO's Schistosomiasis and Intestinal Parasites Control team. "Distribution systems also often do not exist."
The problem of schistosomiasis has long been associated with the growth of agriculture in developing countries. It has also been reported that a schistosomiasis problem often surfaces each time a dam is built or other agricultural development is undertaken. Researchers have correlated a direct link between the existence of stagnant bodies of water, inadequate water, ineffective sanitation systems, and the development of endemic schistosomiasis.
Yet some countries, ranging from Brazil to China to Egypt to Morocco, have shown that easy-to-implement control measures can control and even eliminate schistosomiasis as a public health threat. Among the measures which have proved to be the most effective are repeated treatments of people in known high-endemic areas and the targeting of schoolchildren. Reaching children between the ages of five and 15 is important both in terms of changing behaviour and stopping the effects of infection before permanent damage is done. This age group is the most infected, most likely to show clinical disease and, consequently, most responsible for re-infecting the community.
Schistosomiasis is transmitted by infected patients defecating or urinating schistosome eggs into wells, lakes and other water systems.
Participants also recommended that means of ensuring the delivery and distribution of praziquantel at a low price, the proper management and diagnosis of clinical cases, and the rapid assessment and monitoring of schistosomiasis be developed.
Scientific evidence has shown that a single dose of the 'magic bullet' drug praziquantel can reverse 90% of urinary tract lesions in schoolchildren after only six months, while regular treatment, given to children between the ages of five and 15, can prevent long-term consequences in adulthood. While people treated with praziquantel are cured from the infection and free of clinical diseases, they do tend to get re-infected. To maintain populations free from symptoms, yearly doses – or even treatment once every two years in areas of lower transmission – are necessary.
"People often do not realize the gravity of schistosomiasis infection because the consequences do not develop until years later and, even then, many people do not realize that one is linked to the other,"says Dr Savioli. Moreover, WHO has sometimes had difficulty in securing international support because a vaccine against the parasite was still not available. "But effective control, with the construction of proper water and sanitation systems and changes in behaviour, is possible."
Yet the need of regular re-treatment, especially of schoolchildren, must not stop the international community from addressing this scourge, WHO experts emphasized. "Even if we cannot yet rid the world of this worm, we can cure the disease. It is thus imperative we act now to save these children from the much graver consequences that await them as adults if the infection goes untreated," added Dr Savioli. "To not treat them would be a human travesty, a loss to the development of many countries and a dereliction of our moral duty."
