* To carry out an up to date assessment of the current situation on prevalence and morbidity of urinary (and intestinal) schistosomiasis in the Lower Middle and Upper parts of the Senegal River Basin (SRB) and identify new emerging endemic foci.
* To determine the factors which influence seasonality of transmission in Senegal and Mali. This information will be highly relevant in assessing the best time for intervention procedures.
* To determine the correlation between the development of immunity to Schistosoma haematobium infection and exposure to infection, in areas with different types of transmission (short / long) and in different types of foci (old / recent).
* To determine the effects of agriculture and water development on the spread of schistosomiasis in the SRB.
* To evaluate reinfection patterns and immunity development according to different timings of treatment.
It is expected that the data generated from these studies will give a clear lead as to the most effective control strategy for schistosomiasis in the Senegal River Basin.
These studies will generate important information for future vaccination trials, as it is possible to adapt vaccine formulation (presentation, type of vector) to the different transmission patterns in the field.
It is anticipated that the south-south axis will be strengthened through regional cooperation.
* A survey will be carried out in the Upper part of the SRB (Bakel, Manantali) to assess the current situation on prevalence and morbidity of schistosomiasis and the compatibility of Schistosoma haematobium with the local intermediate hosts (transition zone?). Suitable villages in Mali will be selected for the further studies.
* Epidemiological, morbidity and control studies. During a two year period longitudinal immuno-epidemiological studies will be carried out in 2-3 villages in the department of Podor (seasonal transmission), in 2-3 villages in the department of Dagana (long transmission period) and in 2-3 villages in the Upper Valley around Manantali (periodicity of transmission still to be determined). Before and after treatment, the current situation will be assessed by blood, faecal and urine sampling procedures, clinical examination and echography. Follow-up will be done in relation to timing of initial treatment (before the rainy season).
Immunological studies. Serum isotype analysis of specific human antibodies will be carried out (with emphasis on the IgA response to rSh28GST) and the functional properties of the antibodies (capacity to inhibit GST enzymatic activity) will be assessed. A comparative analysis of the immune responses between populations living in old or new foci, the evolution of the immunological parameters according to the seasonal or perennial transmission type, and the influence of treatment upon the acquisition of immunity to subsequent exposure will be investigated in each selected cohort.
* Transmission studies. Longitudinal malacological studies will be carried out during two years in the selected villages where the transmission sites will be identified. Sampling will be conducted at monthly intervals in Senegal and three-monthly intervals in Mali. Further laboratory studies will characterise fully the compatibility of the collected snails with the parasite species (strains) naturally transmitting in the SRB. These procedures will involve SEM, IEF and RAPD techniques. Physico-chemical characteristics will be measured over time from a number of transmission foci in order to assess the predictability of the likely outcome of potentially newly created transmission foci associated with agricultural development.
Funding SchemeCSC - Cost-sharing contracts
SW7 5BD London