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A major agricultural development project was commissioned to celebrate Ghana's independence in 1957. In the Upper Region along the border with Upper Volta now named Burkina Faso, a total of 185 clay-core dams were constructed in 15 years to enhance village water supplies during the 6-month dry season. In a concentrated area of N.E. Ghana (now the Upper East Region) no fewer than 104 dams were erected in only 3 years. The beneficial impacts of the dams are indisputable, and life today would be unthinkable without them, despite severe problems of neglect of maintenance. Equally undeniable has been a negative disease impact whereby the regional rate of schistosomiasis tripled in 1 or 2 years from 17% to 51% prevalence. Thus, an agriculturally induced hyperendemicity of "red water" or "bloody urine" disease was established. To test the longevity of community disease impact, a survey of hematuria (bloody urine) was conducted in the same areas in 1997. It showed a 40-year ecological entrenchment of elevated levels of schistosomiasis, that is, seemingly permanent alteration of regional disease ecology. The consequences of planning negligence have left a generational impact in that hematuria has become a "rite of passage" for young boys and girls. Unprepared and overburdened rural health care systems are ill-equipped in the face of competing demands to respond to the presence of schistosomiasis. Yet excellent medication is available to break the transmission cycle provided that there is a sufficiency of political will, accompanied by effective, inter-sectoral campaign coordination.

Mega-Acritarchs previously referred to as Chuaria circularis Walcott from the Late Proterozoic Pendjari Formation of Benin and Burkina-Faso (West Africa) are reinvestigated. Both optical microscopy of thin sections and scanning electron microscope study of these fossils, in situ, on the bedding surface of shales, have revealed a considerable thickness and a multilamellar structure of the acid-resistant wall. These two fundamental features had not been recognized in the only previous study of the topotype Chuaria circularis from the Chuar Group (Arizona, USA) using scanning electron microscopy. However, a third feature - a canal-like structure - which had been reported on topotype specimens by transmission electron microscopy, has just been recorded in the present material too using the same technique.

Eight agroclimatic variables related to crop production potential in the semi-arid tropics of India are identified. These are used to assess dry-seeding feasibility, water-logging hazard, risk in agricultural production, cropping patterns and their spatial distribution, using data from 80 locations in India. Regression analysis has been used to identify differences between locations at different scales, i.e., local differences caused by orography, regional differences associated with circulation patterns and continental differences associated with general circulation patterns. Using the data of 8 variables from 199 locations in India and two west African countries (Senegal and Upper Volta) three dissimilarity parameters were derived. The basic dissimilarity observed on a continental scale is that for the same amount of mean annual rainfall the growing season is longer in west Africa than in India. Thus, in west Africa the corresponding wet and dry spells within the available effective rainy period are quite different from India. This will have a significant influence on farming systems in general, and on the identification of adopted crop/cropping systems in particular.

Lack of moisture in the arid and semi-arid regions of Africa is the most fundamental factor limiting crop production. Knowledge of moisture conditions will therefore go a long way to boost crop production. It is against this background that the Hargreaves monthly moisture availability index classification has been employed to identify the various moisture zones and crop zonation in Burkina Faso (formerly Upper Volta). Due to a stimulus of financial incentives, some crops are being expanded beyond their moisture availability limits.

As in most developing countries, Upper Volta is experiencing a very high rate of urban growth. Most of the results of this process may be described as 'uncontrolled' . Almost 50% of the population of Upper Volta's capital, Ouagadougou, lives in so-called 'spontaneous' housing areas, and this percentage is increasing . Legislative measures cannot cope with a phenomenon of this magnitude . Successful intervention can be achieved only by socio-economic actions. With its limited financial resources, how can the Government of Upper Volta define and engage in a policy with regard to urbanization which would allow the improvement of living conditions?

Summary The authors give some historical data and the geographical distribution of dengue fever in Africa. They describe circumstances in which they isolated 96 strains of dengue 2 virus from wild mosquitoes collected in Ivory Coast and Upper Volta, during the dry or semi-humid savanna from May to November, 1980. Aedes luteocephalus and Aedes furcifer/taylori were the two main species from which the virus was isolated by the classical inoculation technique in newborn mice. Identification was carried out by haemagglutination inhibition and complement fixation tests, and further characterization was performed by the immunofluorescence test with monoclonal specific antibodies, at the WHO Collaborating Center for Arboviruses Reference and Research in Dakar. Epidemiological serosurveys carried out in Ivory Coast after the finding of the epizootic showed the absence of human infection. Possible animal reservoirs, such as monkeys, have not yet been studied. The isolation of virus from one pool of male mosquitoes, A. furcifer/taylori, could at least partially explain the maintenance of the virus in wilderness areas.

Onchocerciasis is one of the most serious blinding diseases in the world, affecting between 20 and 25 million people, of whom 200-500 thousand are blind. In Africa more than half of the countries on the continent are affected, the basin of the Volta river containing one of the largest endemic areas. In this area the unique Onchocerciasis Control Program (OCP) is being undertaken, involving Benin, Ghana, Ivory Coast, Mali, Niger, Togo and Upper Volta. In this region, surveys have shown that 14.78% of the population have microfilariae in their skin biopsies, while in hyperendemic villages the figure rises to 75.2%. In such a village the prevalence of blindness rises steeply with age, from 0% under age 20, to over 40% in the over 50 age group. Various environmental factors relevant to the prevalence and incidence of systemic and ocular onchocerciasis are discussed, and pharmacologic treatment modalities are described. Prevention activities, centred around vector control by insecticides, have been dramatically effective.

This paper presents the experiences had in delivering health services to pastoral Tuareg and Maure nomads living in the West African sahel. Because of the rudimentary nature of the existing general health services structure and existing attitudes towards health services among nomads, the mass campaign technique was employed. Between 1968 and 1971 campaigns were directed at Tuareg and Maure groups living in Mali, Mauritania, Niger, Senegal and Upper Volta. Such campaigns consisted of preparatory, planning and execution phases. During the first two, nomadic movements were studied and program logistics planned in detail. Because nomads have historically resisted the payment of taxes on themselves and their livestock, special efforts were made to completely dissociate health temas from administrative authorities associated with tax collection. The low population density of the sahel, the dispersion of nomads over a wide geographic area and the long distances between individual nomad camps necessitated the investment of man hours and gasoline far in excess of those invested in campaigns for sedentary farmers living in the same areas. In one program for both nomads and sedentaries living in the same topographic zone, a comparison of costs and resources necessary was made between the two sets of medical teams established. The operational costs for the program for nomads was eleven-fold more than that for the sedentary agricultural population. The short term goals of the program were: (1) the delivery of specific immunizations; (2) health education; and (3) a demonstration of the complete separation of health service delivery and tax collection. The long term goals were: (1) the extension of general health services to the nomadic population; and (2) the use of fixed curative medical facilities by the nomadic population. Crucial to the program's success was the delivery of a service such as measles immunization which had an immediate and striking effect on the health of the community.

To arrange the 190 locations in India, Senegal and Upper Volta into finite groups, numerical taxonomic techniques were adopted, using 11 agroclimatic variables derived from parts I, II and III of this study. The results obtained using the data matrix of 7 principal coordinates with Euclidean metric — unweighted pair group method using arithmetic averages (UPGMA) fusion strategy appear to be the most suitable to identify groups formed in India and West Africa. In general, this study separated the highly undependable locations with different effective rainy periods. The groups identified are not homogeneous in terms of dependability defining dry-seeding feasibility, at the lower end of the range, and water-logging hazards. Therefore, to overcome this problem, the groups were first arranged into 3 broad zones, namely arid, semi-arid and sub-humid according to a modified Thornthwaite approach, and the semi-arid locations were further divided into 5 zones based on the effective rainy period related to the cropping pattern. As the primary groupings refer to the most stable situation, they were again divided into 5 sub-zones each based on the level of dependability, which was characterized by the standard deviation of the commencement time of sowing rains. To account for some of the operational problems, such as water-logging, availability of field work days for cultural operations, etc., they were further divided into groups and sub-groups based on wet and dry spells and aridity index. The derived zones and sub-zones of the semi-arid tropics are straight forward and easily memorised, and make sense agronomically. With the given classification structure it is easy to add new locations without further numerical analysis.