Ecology of potential hosts of schistosomiasis in urban environments of Chaco, Argentina

• Autores: Rumi, A.; Bechara, J.A.; Hamann, M.I.; Ostrowski De Núñez, M.
• Año de publicación: 2002
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Malacologia 2002;44(2):273-288
• Materia: Chaco Region; Gastropoda; Intermediate-hosts; Paraná River; Planorbidae; Schistosomiasis; Vector-ecology; Ancylidae; Biomphalaria; Biomphalaria straminea; Biomphalaria tenagophila; Canna glauca; Cimex; Drepanotrema; Drepanotrema cimex; Drepanotrema lucidum; Eichhornia; Eichhornia crassipes; Gastropoda; Hydrobiidae; Hydrocotyle; Hydrocotyle ranunculoides; Panicum; Panicum elephantipes; Pistia stratiotes; Planorbidae; Stratiotes
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

Some of the Biomphalaria species living in Chaco, such as B. straminea and B. tenagophila, are natural transmitters of schistosomiasis in Brazil, while those of the genus Drepanotrema are not intermediate hosts of the disease. The aim of the present work was to analyze the importance of a selected set of environmental variables in explaining patterns of distributions and relative abundance of planorbid gastropod assemblages. The study sites were located in urban areas of Resistencia City, Chaco Province, and the environmental variables measured were substratum (macrophytes), water quality (pH, O2, nutrients, among others), as well as other gastropods (Ancylidae, Hydrobiidae and Ampullaridae). Seasonal samplings were carried out in four distinct environments. Thirty-one quantitative samples of gastropods and environmental variables were obtained. In canonical correspondence analysis (CCA), seven environmental variables were retained after a stepwise forward selection, from a total of 26, including [N-NH4+], O2%, and the macrophytes Eichhornia crassipes, Pistia stratiotes, Panicum elephantipes, Hydrocotyle ranunculoides and Canna glauca. They explained 62% of the variation in planorbid association. Canna glauca was the most significant variable, being positively correlated with all of the species of Drepanotrema. Axis I separates B. tenagophila from B. straminea, along a gradient related to increasing O 2% and P. elephantipes abundance, as well as decreasing [N-NH 4+] and P. stratiotes. Axis II separates D. lucidum, D. anatinum and D. cimex from the other planorbid species along a gradient associated with decreasing abundances of H. ranunculoides and C. glauca. Some common aquatic macrophytes, and to a lesser extent, dissolved oxygen and ammonium in water, may be useful indicators of favorable environmental conditions for potential intermediate hosts of schistosomiasis in Chaco Region.
Fil:Ostrowski De Núñez, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.