Avaliação preliminar de impacto ambiental sobre a fauna de pequenos mamíferos e suas taxas de infecção por Trypanosoma cruzi e Hantavírus na área de influência da Usina Hidrelétrica Espora, Aporé - GO

Abstract

The objective of this study was to evaluate possible environmental impacts caused by the construction and filling of the Espora hydroelectric power plant s reservoir (localized in Aporé, Serranópolis and Itarumã GO, Brasil) on small mammal fauna and their Hantavirus and Trypanosoma cruzi infection rates. Small mammals were captured in periods pre- and postfilling of the reservoir between 2003 and 2007. The taxonomic identification of rodents and marsupials was performed through morphology and karyotyping. Serological diagnostic of Hantavirus infection was performed through IgG (Andes antigen) Enzime Immunoassay (ELISA), while indirect immunofluorescence (RIFI) and hemoculture were used to diagnose T. cruzi infection. In total, among rodents and marsupials, 358 specimens were captured, resulting in a total species richness of 17 species. Didelphis albiventris, Gracilinanus agilis and Marmosa murina were the most abundant marsupial species, being responsible for 94.5% of the captures. Among rodents, Hylaeamys megacephalus, Calomys tener and Necromys lasiurus were the most abundant, representing 44.04% of the captures. Of all captured specimens, 145 were serologically tested for T. cruzi infection, being 33.8% found positive. Out of 104 hemoculture testing performed for T. cruzi infection 10 were positive. Of the 193 rodents captured, 26.4% were tested for Hantavirus serum prevalence, from which only 2 specimens of Rattus rattus were found positive. In the post-filling period, there was a reduction in the proportion of captured rodents in relation to captured marsupials, and also in male to female ratio of G. agilis, M. murina and N. lasiurus. Species richness did not change with reservoir filling. T. cruzi and Hantavirus infection rates in the post-filling period were not statistically different than in the pre-filling period. The small mammals low infection rates, by either etiological agent, after filling the reservoir indicate a low probability of Hantavirus and Chagas Disease emergence after implementation of the Espora hydroelectric power plant in the area. Also, our results indicate that this undertaking does not cause a great impact on small mammal fauna, considering the relatively high species richness after filling the reservoir.