Transmission of schistosomiasis in an urban population and prevalence of intestinal helminthiasis in Bamako, Mali

Parasitological, malacological and anthropological studies were performed to assess the prevalence of Schistosoma haematobium and S. mansoni in schoolchildren living in the suburban area of Bamako. A total of 1017 schoolchildren aged 6-14 years were selected in two different areas between September 1997 and December 1999. In Djikoroni, the prevalence of S. haematobium and S. mansoni was 80.7% (339/420) and 22.8% (85/372) respectively. There was no significant difference of prevalence and intensity of infection with S. haematobium between schools, gender and age (p > 0.05), whereas, those of S. mansoni were higher in the vicinity of (+/- 100 m from) major sites where infected Biomphalaria pfeifferi were found (p < 0.001). In Niomirambougou, S. haematobium was prevalent in 46.7% (279/597) and S. mansoni in 28.2% (134/475). Boys and children aged 11-14 years were more infected (p < 0.001). Associated intestinal helminths (Hymenolepis nana, Necator americanus and Ascaris lumbricoides) were relatively scarce (prevalence < 1%). The prevalences of schistosome infected snails intermediate host were relatively high, 49.3% (100/203) in B. pfeifferi, 20.6% (88/138) in B. truncatus and 24.1% (7/29) in B. globosus. We recorded a total of 2514 water contacts about which 1130 in December and 1384 in January. Most of the children, 42.9% (1077/2511) were attracted to water bodies for bathing, swimming and playing, suggesting the lack of recreational facilities in these areas. Developing local control programmes in schools located in the vicinity of water bodies would contribute to break the parasite transmission cycle in Bamako.     

The RAFT network: 5 years of distance continuing medical education and tele-consultations over the Internet in French-speaking Africa

Continuing education of healthcare professionals is a key element for the quality and efficiency of a health system. In developing countries, this activity is usually limited to capitals, and delocalized professionals do not have access to such opportunities, or to didactic material adapted to their needs. This limits the interest of such professionals to remain active in the periphery, where they are most needed to implement effective strategies for prevention and first-line healthcare. Telemedicine tools enable the communication and sharing of medical information in electronic form, and thus facilitate access to remote expertise. A physician located far from a reference center can consult its colleagues remotely in order to resolve a difficult case, follow a continuous education course over the Internet, or access medical information from digital libraries or knowledge bases. These same tools can also be used to facilitate exchanges between centers of medical expertise: health institutions of a same country as well as across borders. Since 2000, the Geneva University Hospitals have been involved in coordinating the development of a network for eHealth in Africa (the RAFT, Réseau en Afrique Francophone pour la Télémédecine), first in Mali, and now extending to 10 French-speaking African countries. The core activity of the RAFT is the webcasting of interactive courses. These sessions put the emphasis on knowledge sharing across care professionals, usually in the form of presentations and dialogs between experts in different countries. The technology used for the webcasting works with a slow (25 kbits/s) internet connection. Other activities of the RAFT network include visioconferences, teleconsultations based on the iPath system, collaborative knowledge bases development, support for medical laboratories quality control, and the evaluation of the use of telemedicine in rural areas (via satellite connections) in the context of multisectorial development. Finally, a strong emphasis is put on the development of capacities for the creation, maintenance, and publication of quality medical didactic contents. Specific courses are organized for the national coordinators of the network to develop these competencies, with the help of the Health-On-the-Net Foundation. The richness of the plurality of knowledge and know-how must be steered towards emulation and sharing, respectful of each partner's identity and culture. Collaborations with UNESCO and WHO have been initiated to address these challenges.     

Detection and quantitation of stem cell factor (kit ligand) in the synovial fluid of patients with rheumatic disease

OBJECTIVE: To identify and quantitate stem cell factor (SCF; kit ligand) in the serum and synovial fluid (SF) of patients with rheumatoid arthritis (RA) and to compare these values with those measured in normal serum, RA serum, SF of patients with other rheumatic diseases, and conditioned medium from cultured synoviocytes. METHODS: SCF was measured in serum, SF, and conditioned synovial cell culture medium by a sensitive ELISA. Results were correlated with hematologic variables including white blood cell count, hemoglobin, platelet count, erythrocyte sedimentation rate, and rheumatoid factor. RESULTS: SCF levels in RA SF exceeded those measured in RA serum, osteoarthritis SF, and SF from patients with other inflammatory arthropathies. SCF was detectable in conditioned medium from cultured synoviocytes. CONCLUSION: High levels of SCF are present in RA serum and SF. Local production of SF may influence expansion of myeloid progenitor cells and mast cell function in RA.     

Assessment of Internet-based tele-medicine in Africa (the RAFT project).

The objectives of this paper on the Réseau Afrique Francophone de Télémédecine (RAFT) project are the evaluation of feasibility, potential, problems and risks of an Internet-based tele-medicine network in developing countries of Africa. The RAFT project was started in Western African countries 5 years ago and has now extended to other regions of Africa as well (i.e. Madagascar, Rwanda). A project for the development of a national tele-medicine network in Mali was initiated in 2001, extended to Mauritania in 2002 and to Morocco in 2003. By 2006, a total of nine countries are connected. The entire technical infrastructure is based on Internet technologies for medical distance learning and tele-consultations. The results are a tele-medicine network that has been in productive use for over 5 years and has enabled various collaboration channels, including North-to-South (from Europe to Africa), South-to-South (within Africa), and South-to-North (from Africa to Europe) distance learning and tele-consultations, plus many personal exchanges between the participating hospitals and Universities. It has also unveiled a set of potential problems: (a) the limited importance of North-to-South collaborations when there are major differences in the available resources or the socio-cultural contexts between the collaborating parties; (b) the risk of an induced digital divide if the periphery of the health system in developing countries is not involved in the development of the network; and (c) the need for the development of local medical content management skills. Particularly point (c) is improved through the collaboration between the various countries as professionals from the medical and the computer science field are sharing courses and resources. Personal exchanges between partners in the project are frequent, and several persons received an education at one of the partner Universities. As conclusion, we can say that the identified risks have to be taken into account when designing large-scale tele-medicine projects in developing countries. These problems can be mitigated by fostering South-South collaboration channels, by the use of satellite-based Internet connectivity in remote areas, the appreciation of local knowledge and its publication on-line. The availability of such an infrastructure also facilitates the development of other projects, courses, and local content creation.     

Identifying and quantifying genotypes in polyclonal infections due to single species

Simultaneous infection with multiple pathogens of the same species occurs with HIV, hepatitis C, Epstein-Barr virus, dengue, tuberculosis, and malaria. However, available methods do not distinguish among or quantify pathogen genotypes in individual patients; they also cannot test for novel insertions and deletions in genetically modified organisms. The strategy reported here accomplishes these goals with real-time polymerase chain reaction (PCR) and capillary electrophoresis. Real-time PCR with allotype-specific primers defines the allotypes (strains) present and the intensity of infection (copy number). Capillary electrophoresis defines the number of genotypes within each allotype and the intensity of infection by genotype. This strategy can be used to study the epidemiology of emerging infectious diseases with simultaneous infection by multiple genotypes, as demonstrated here with malaria. It also permits testing for insertions or deletions in genetically modified organisms that may be used for bioterrorism.     

Spatial patterns of infant mortality in Mali: the effect of malaria endemicity

A spatial analysis was carried out to identify factors related to geographic differences in infant mortality risk in Mali by linking data from two spatially structured databases: the Demographic and Health Surveys of 1995-1996 and the Mapping Malaria Risk in Africa database for Mali. Socioeconomic factors measured directly at the individual level and site-specific malaria prevalence predicted for the Demographic and Health Surveys' locations by a spatial model fitted to the Mapping Malaria Risk in Africa database were examined as possible risk factors. The analysis was carried out by fitting a Bayesian hierarchical geostatistical logistic model to infant mortality risk, by Markov chain Monte Carlo simulation. It confirmed that mother's education, birth order and interval, infant's sex, residence, and mother's age at infant's birth had a strong impact on infant mortality risk in Mali. The residual spatial pattern of infant mortality showed a clear relation to well-known foci of malaria transmission, especially the inland delta of the Niger River. No effect of estimated parasite prevalence could be demonstrated. Possible explanations include confounding by unmeasured covariates and sparsity of the source malaria data. Spatial statistical models of malaria prevalence are useful for indicating approximate levels of endemicity over wide areas and, hence, for guiding intervention strategies. However, at points very remote from those sampled, it is important to consider prediction error.     

Molecular identification of sympatric chromosomal forms of Anopheles gambiae and further evidence of their reproductive isolation

Three chromosomal forms of Anopheles gambiae s.s., designated as Bamako, Mopti and Savanna, were studied for diagnostic PCR assays based on the analysis of the X-linked ribosomal DNA (rDNA). The study was performed on a 1.3 kb fragment containing part of the 28S coding region and part of the intergenic spacer region. The amplified material was cut with fourteen restriction enzymes to detect Restriction Fragment Length Polymorphisms (RFLPs). The enzymes Tru 9I and Hha I produced patterns of DNA bands which differentiated Mopti from Savanna and Bamako; moreover, a distinct 'hybrid' pattern was recognized in the F1 female progeny from the cross of Mopti with either one of the other two chromosomal forms. The diagnostic significance of the PCR-RFLP assay was verified on 203 karyotyped females from field samples collected in two villages in Mali and one village in Burkina Faso. Agreement was observed between the chromosomal and the molecular identifications. No 'hybrid' molecular patterns were detected even among carriers of rare heterokaryotypes hypothetically produced by crosses between Mopti and Savanna. The results confirm previous observations indicating barriers to gene flow within An. gambiae s.s. and supporting the specific status of the taxonomic units proposed on cytogenetic ground.     

Mapping malaria transmission in West and Central Africa

We have produced maps of Plasmodium falciparum malaria transmission in West and Central Africa using the Mapping Malaria Risk in Africa (MARA) database comprising all malaria prevalence surveys in these regions that could be geolocated. The 1846 malaria surveys analysed were carried out during different seasons, and were reported using different age groupings of the human population. To allow comparison between these, we used the Garki malaria transmission model to convert the malaria prevalence data at each of the 976 locations sampled to a single estimate of transmission intensity E, making use of a seasonality model based on Normalized Difference Vegetation Index (NDVI), temperature and rainfall data. We fitted a Bayesian geostatistical model to E using further environmental covariates and applied Bayesian kriging to obtain smooth maps of E and hence of age-specific prevalence. The product is the first detailed empirical map of variations in malaria transmission intensity that includes Central Africa. It has been validated by expert opinion and in general confirms known patterns of malaria transmission, providing a baseline against which interventions such as insecticide-treated nets programmes and trends in drug resistance can be evaluated. There is considerable geographical variation in the precision of the model estimates and, in some parts of West Africa, the predictions differ substantially from those of other risk maps. The consequent uncertainties indicate zones where further survey data are needed most urgently. Malaria risk maps based on compilations of heterogeneous survey data are highly sensitive to the analytical methodology.