Press Release WHO/91
4 December 1998
SCHISTOSOMIASIS THE SILENT SCOURGE OF DEVELOPMENT
Over 200 million people worldwide 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 endemic.
Control of this scourge is straightforward but interest in it has waned in recent years. Meeting at the World Health Organizations (WHO's) Geneva headquarters from 2 to 4 December, over 50 experts from 22 countries looked 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. Distribution systems also often do not exist," said Dr Lorenzo Savioli, head of WHO's Schistosomiasis and Intestinal Parasites Control team.
The schistosomiasis problem has long been associated with the growth of agriculture in developing countries. It has been noted that a schistosomiasis problem surfaces each time a dam is built or other agricultural development is undertaken: there is a direct link between the existence of stagnant bodies of water, inadequate water and 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 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. Moreover, WHO has sometimes had difficulty in securing international support because we do not yet have a vaccine against the parasite. But effective control, with the construction of proper water and sanitation systems and changes in behaviour, is possible," said Dr Savioli.
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."
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