María C. Lurá

El agua subterránea como agente transmisor de protozoos intestinales

Introduccion.El objetivo del presente trabajo fue establecer si habia asociacion entre el consumos de agua obtenida de fuentes subterraneas,solo desinfectada con cloro,y la presencia de protozoos intestinales en una poblacion pediatrica.Poblacion.Se estudiaron cuatro grupos de ninos,de cuatro meses a doce anosde edad,que compartian similares condiciones socio-economicas y sanitarias.Los grupos A(n=34)B(n=36) y C(n=45)consumian agua de rede proveniente de fuentes subterraneas,solo tratada con cloro antes de ser distribuida.El grupo control,D(n34)consumia agua de fuente superficial con tratamiento de potabilizacion convencional completo.Material y Metodos.En cada grupose analizo el agua,desde el punto de vista fisicoquimico,bacteriologico y parasitologico y se realizaron cultivos coproparasitologicos seriados a los ninos seleccionados.Se realizo,ademas,una encuesta a los padres.Conclusiones.En las muestras estudiadas las diferencias relativas existentes entre el grupo control y el resto de los grupos estudiados permitirian inferir que existe un alto riesgo de infeccion con protozoos intestinales cuando se consume agua contaminada de origen subterraneo que solo fue clorada antes de su distribucion

El tratamiento antihelmíntico selectivo frente al tratamiento masivo: experiencia en dos comunidades hiperendémicas

OBJECTIVE: To compare the prevalence and intensity of soil-transmitted nematode infection among children from two hyperendemic communities who were treated with antihelminthic drugs under two different regimens: selective or individual treatment was administered to members of one of the communities, and repeated mass treatment was given to the control community. METHODS: The study population was comprised of 909 children of both sexes between the ages of 2 and 13 from two peri-urban communities: Las Lomas and El Abastos, both in Santa Fe, Argentina. A prospective, longitudinal, quasi-experimental study was carried out in these communities. During the 22-month study period, 5 parasitologic controls were performed and results were qualitatively and quantitatively examined. Treatment with antihelminthic drugs was given at controls 0, 2, 3, and 4. At Las Lomas, selective treatment was administered to those in sample A (n = 55) who were positive for parasites; in El Abasto, mass treatment was given to all children, including those in sample B (n = 50). Both samples received follow-up. RESULTS: The prevalence and intensity of A. lumbricoides infections were found to be significant in El Abasto. No differences were detected in the case of T. trichiura. When prevalence and parasitic burden of A. lumbricoides were compared among controls within a single community (at the beginning and end of the study), no significant differences were observed in sample A, but a significant difference was seen in sample B. Insofar as T. trichiura is concerned, there were significant differences among controls in both samples. CONCLUSIONS: Only repeated and massive treatment significantly lowered the prevalence and intensity of A. lumbricoides infections during the study period.

Phenotypic and Genotypic Variability in Cercospora kikuchii Isolates from Santa Fe Province, Argentina

More than 100 fungal diseases affecting soybean (Glycine max (L.) Merr.) culture have been found worldwide, though only 35 of them are of great economic concern since they cause a 10 to 15% yield decrease (Ivancovich & Botta, 2003; Yeh & Sinclair, 1980). In Argentina, “Late-cycle diseases” (LCD) constitute a complex of infections affecting the culture of this leguminous, particularly in the reproductive stages. The first symptoms appear from the onset of carpel formation, thus producing premature plant maturation, a reduction in yield (5 to 8%) and seed quality loss. Due to the climate conditions of the region, leaf blight and purple seed stain, is one of the LCD prevailing in the central-northern region of Santa Fe Province (Formento, 2005; Ivancovich & Botta, 2003). The causal agent of the disease is the fungus Cercospora kikuchii (T. Matsumoto & Tomoyasu) M.W. Gardner, which produces irregular injuries on the leaves, forming reddish-purple necrotic areas, pale pink to dark purple stains on the seeds, together with cracks on the outer coat (Formento, 2005). C. kikuchii belongs to the Cercospora taxonomic complex, which is assumed to be host-specific (Crous & Braun, 2003), and therefore its species are normally identified from the phenotypic characteristics they show when grown on their natural substrate, being much more difficult to be characterized from artificial media (Almeida et al., 2005; Gams et al., 2007). One of the most important factors determining the pathogenicity of this fungus is the production of cercosporin, a red exotoxin (Kuyama & Tamura, 1957; Upchurch et al.,1991). Another aspect to consider is the genetic variability found in some fungi, which has determined the description of different races; that is why the use of some methodology to detect interand intraspecific variations between isolates is recommended (Kuyama & Tamura, 1957). In this sense, the Random Amplified Polymorphic DNA (RAPD) technique allows the differentiation between strains since amplification focuses only on the whole genome (Tigano et al., 2003; Williams et al., 1990). Although some Brazilian research groups have been studying aspects related with this phytopathogen (Almeida et al., 2003) only a few reports have been found in Argentina and, in particular in Santa Fe Province, about epidemiology and population structure of C. kikuchii.