Observations on the compatibility between Bulinus spp. and Schistosoma haematobium in the Senegal River basin

Snail-infection experiments were carried out with a number of different species and populations of #Bulinus and isolates of #Schistosoma haematobium. The parasites came from six localities of the Senegal River basin (SRB), in the Lower Valley (Mbodiene), Middle Valley (Podoe, Diatar, Nguidjilone) and Upper Valley (Aroundou and Galladé). Isolates of #S. haematobium from the Middle and Upper Valleys all showed some compatibility with laboratory-bred #B. truncatus from Mali, but none of these isolates was compatible with laboratory-bred #B. truncatus originating from Senegal. #Schistosoma haematobium from Diatar (Middle Valley) was compatible with #B. senegalensis, whereas #S. haematobium from Mbodiene (Lower Valley), which is naturally tranmitted by #B. globosus, was compatible with #B. senegalensis and #B. truncatus. These data demonstrate that different isolates of #S. haematobium from different regions of the SRB exhibit distinct intermediate-host specificities, which in turn will have an effect on the epidemiology of the disease, including the periods of transmission. It is apparent that, in addition to #B. senegalensis and #B. globosus, #B. truncaus$, the most widespread bulinid snail in the SRB, may be playing a role in the epidemiology of urinary schistosomiasis. This conclusion has obvious implications for the future spread of urinary schistosomiasis in the SRB. Chemical and physical measurements from assorted habitats along the SRB, including pH, temperature, salinity, conductivity, and resistivity, are also reported. (Résumé d'auteur

The effects of irrigated agriculture on the transmission of urinary schistosomiasis in the Middle and Upper Valleys of the Senegal River basin

The importance of the increase in irrigated land on the perimeters of the Middle and Upper Valleys of the Senegal River basin, on the prevalence and intensity of urinary schistosomiasis, was investigated. Surveys were conducted, in May-June 1997, to determine the prevalence and intensity of #Schistosoma haematobium$infection among 1445 children aged 7-14 years : 1011 in 10 villages near Matam, and 434 in 4 villages near Bakel. Macrohaematuria was present in seven of the study villages (four near Matam and three near Bakel), whereas microhaematuria was present in all the villages, with prevalences of 10$ infected with schistosome cercariae were recovered from the Senegal River. (D'après résumé d'auteur

COMPARATIVE ANALYSES OF THE NEUROPEPTIDE-F (NPF)-RELATED AND FMRFAMIDE-RELATED PEPTIDE (FARP)-IMMUNOREACTIVITIES IN FASCIOLA-HEPATICA AND SCHISTOSOMA SPP

This article explores the potential offered by complexity theories for understanding language learners’ sense of self and attempts to show how the self might usefully be conceived of as a complex dynamic system. Rather than presenting empirical findings, the article discusses existent research on the self and aims at outlining a conceptual perspective that may inform future studies into the self and possibly other individual learner differences. The article concludes by critically considering the merits of a complexity perspective but also reflecting on the challenges it poses for research