Public Health In Africa - Fight Against Bilharzia Still Goes On
Poku Adaa
The 'embarrassing disease' or Bilharzia afflicts millions of people all over the world, especially in Africa. A relatively new drug therapy for the disease was the topic of a public lecture organised by the Anderson Chemical Society in Scotland recently. POKU ADAA reports on the substance of the lecture and reviews the prevalence of the disease in Africa and past and present national and international efforts to control it.IN 1978, a new drug called Vansil was launched in Africa as a cure for the debilitating disease, Bilharzia which afflicts millions of people in the Continent. At the beginning of November this year, at a public meeting in Glasgow Scotland, Dr J. Harris of the Pfizer Pharmaceutical Company delivered a magnificent lecture on the development and usefulness of the new drug which also has a technical name, Oxamniquine.
The causes of the disease, according to the eminent speaker, arise out of poor sanitary conditions and ineffective public health programmes and fre- quent contact with dirty and unsafe water supplies. At this point, the audience was treated to a series of beautiful colour slides showing African women and children, some naked, wading through, washing in and collecting water from a swamp pool. The sighs and murmurs of the audience was not least surprising, especially, Africa being the depository of every conceivable ailment under the sun.
The drug has proved effective compared with existing drugs on the market and has been proved in tests in Brazil to be non-toxic, can be easily administered orally and is also inexpensive, so said the speaker. Asked whether African Health Authorities have accepted the drug, he replied in the affirmative adding that the World Health Organisation has approved it and listed it under its permissible drugs list.
Bilharzia is one of the most widespread parasitic diseases in tropical areas affecting over 90 million people in Africa alone. It is caused and transmitted by four different types of parasites which are carried by water-borne snails found in rivers, lakes, streams and swamps, especially those turned dirty and stenchy by the presence of accumulated domestic refuse and rotten debris.
According to a World Health Organisation (WHO) Bulletin report published in 1981, about thirteen countries in Africa have over 40% of their popu- lations constantly exposed to the disease. In Ghana, the figure is 48.5%, Chad 85.8%, Gambia 72.3%, Liberia - 46.6%, Mali - 59.2%, Sierra Leone - 48.9%, Nigeria 19.1%. The most severely affected countries in Africa were listed as Angola, Central African Republic, Chad, Egypt, Ghana, Malagasy, Malawi, Mozambique, Senegal, Sudan, Tanzania and Zambia. The dis- tribution of the disease is greatly accelerated by the creation of irrigation systems, man-made lakes and several other types of water development schemes in agriculture.
In Ghana, as an example, the construction of a dam across the Volta river at Akosombo created a man made lake of about 8,500 square kilometres of surface area, so providing a fertile breeding ground for the water snails which transmit the parasites to man. The considerable inter-village movement of the communities surrounding the lake, mainly fishermen, has contributed to the spread and intensity of the disease.
Similarly, the Gezira irrigation development in the Sudan has been the cause of the high incidence of the disease in that part of the country. The extensive rice fields in Yagoua in North Cameroon is another area where inci dence of Bilharzia is high.
There are three ways of attacking the disease: either through drug therapy which only attempts to kill the parasite once it has entered the human body, or through control of the snail which carries the parasite and transfers it to humans by spraying the infected water bodies with specially formulated chemicals. Thirdly, control can be achieved by rigid adoption of effective public health programmes.
Drug therapy is useful where the infection has taken roots and effort is required to contain the spread. The WHO has listed thirteen approved drugs as being permissible for use as cures against the parasite attack. The most widely used ones at the present time are Niridazole used in 41 countries and Hycanthone used in about 16 countries. It is alleged in medical circles that these drugs may have certain serious side effects.
Current international consensus indicates that Metrifonate, Praziquantel and Oxamniquine have effective specific action against particular parasites. It was revealed at the public lecture referred to earlier on that two drugs, Praziquantel and Oxamniquine when used as a mixture does provide the greatest cure than using each separately. It seems inconceivable that two drugs manufactured by two competing companies will easily accept such a commercially unattractive proposition. To be fair and honest, many a drug company will be more interested in profit than healthy African infants. Nevertheless, that revelation has interesting moral and commercial implications.
Large-scale treatment campaigns in several areas have been successful due to the co-operation of international agencies. A WHO/UNDP project was established in 1971 in Ghana to study the spread and incidence of the disease. This project was assisted by extra funds from the Government of Ghana, the Edna McConnel Clark Foundation, the Government of the Netherlands, the United Kingdom Overseas Development Department and the Canadian International Development Agency. The study centred initially around 26 villages around the south east section of the Afram branch of the Volta Lake.
Approximately 15,000 people in this area were involved in the campaign exercise with treatment consisting of hospital screening and spraying of large areas of the district. The programme has achieved an acceptable level of control of the disease and the measures have had some success.
In Nigeria, studies and mass treat- ment campaigns have been carried out in the Ajara community of Badagry and particular attention has been paid to children who have generally been most affected. There have been successful campaigns reported in Egypt, Sierra Leone, Tanzania, Ethiopia, Sudan and Senegal. In Tunisia, results of a ten year campaign have been reported to have progressively brought the disease under control.
In the control of the water-borne snails which transmit the parasites, several chemicals have been employed although it has been reported that there are certain plants that are effective in killing the snails. This offers a new impetus since synthetic chemicals are expensive to import and cannot sustain any long term control programmes. Over the last half century, over 1,000. plant species around the world have been identified. Typical ones are some types of berries successfully used this way in Ethiopia and the Sudan. In Ethiopia, large scale cultivation of the plant has practically aided the control of Bilharzia. The cashew nut has also been used for the same purpose in Mozambique. It is anticipated that in many areas where the disease is deeply rooted, a combination of using locally cultivated plants and synthetic chemicals will be the quickest and most cost-effective way to reduce the spread and intensity of infection.
The main public health and environmental control programmes recommended include health education, improvement of existing water supplies, provision of sanitary facilities to avoid dumping of domestic refuse into community water supplies, provisions of sanitary facilities to avoid dumping of domestic refuse into community water supplies. These measures have to proceed side by side with drug therapy and other control programmes, as indeed happens in many countries. In addition, WHO has recommended training and career structures for personnel involved in the various control arms of the eradication campaigns
The most anticipated technique will be vaccination. However, in spite of high quality research work in many parts of the world, there is still a long way to go for developing vaccine control for the disease in humans.
Every nation has the government that it deserves.
— Joseph de Maitre - Letter on the subject of Russia -1811
