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In the present study, we compared Trypanosoma cruzi infection in four native mammals from a hyperendemic area of Chagas disease in Chile for two different periods to assess the occurrence of interannual variation (1999-2000 vs. 2005-2006). Parasite detection in mammals is performed by polymerase chain reaction assays and confirmed by Southern blot analysis and hybridization test with a universal probe. Results showed significant differences in the levels of T. cruzi infection between the compared periods. We suggest that the major El Niño event occurred in 1997-1998, a large-scale global climatic fluctuation, could be indirectly explaining the extremely high T. cruzi infection in 1999-2000 by means of a time-lag response of the wild transmission cycle of Chagas disease in semiarid Chile after the irruption of small rodent populations.

Abstract. We show Koszulness of the prop governing involutive Lie bialgebras and also of the props governing non-unital and unital-counital Frobenius algebras, solving a long-standing problem. This gives us minimal models for their deformation complexes, and for deformation complexes of their algebras which are discussed in detail.Using an operad of graph complexes we prove, with the help of an earlier result of one of the authors [W3], that there is a highly non-trivial action of the Grothendieck-Teichmüller group GRT 1 on (completed versions of) the minimal models of the properads governing Lie bialgebras and involutive Lie bialgebras by automorphisms. As a corollary one obtains a large class of universal deformations of any (involutive) Lie bialgebra and any Frobenius algebra, parameterized by elements of the Grothendieck-Teichmüller Lie algebra.We also prove that, for any given homotopy involutive Lie bialgebra structure in a vector space, there is an associated homotopy Batalin-Vilkovisky algebra structure on the associated Chevalley-Eilenberg complex.

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Fifty-six Trypanosoma cruzi stocks from Chile and neighboring countries and different hosts, humans, and Triatoma infestans and Mepraia sp., vectors of domiciliary and natural environments were characterized by using three molecular markers. These were cytochrome b (Cyt b) gene sequencing, minicircle DNA blotting, and hybridization with five genotype-specific DNA probes and nuclear analysis of 1f8 and gp72 by polymerase chain reaction-restriction fragment length polymorphism. The results with all three molecular markers are concordant, with minor limitations, grouping T. cruzi stocks into four discrete typing units (DTUs) (TcI, TcII, TcV, and TcVI). TcI and TcII stocks were heterogeneous. TcI and TcII stocks were clustered in two main subgroups determined by Cyt b gene sequencing and minicircle hybridization. However, TcV and TcVI stocks were homogeneous and not differentiated by Cyt b gene sequencing or minicircle DNA hybridization. The discriminatory power and limitations of the molecular markers are discussed, as well as the distribution of the four DTUs in the domiciliary and sylvatic transmission cycles of Chile and the limitations of each marker for molecular epidemiological studies performed with T. cruzi stocks rather than the analysis of direct T. cruzi samples from natural hosts.

Abstract. We evaluated Trypanosoma cruzi infection in 397 wild Mepraia gajardoi specimens from five coastal localities in northern Chile by detection of minicircle DNA by polymerase chain reaction. The wild capture sites were classified into two ecotopes: a fully wild ecotope (ecotope 1) and a wild ecotope near human dwellings (ecotope 2). Infection rates varied between 11% and 27%. Minicircle hybridization assays showed that T. cruzi lineages Tc II and Tc VI were commonly detected in ecotope 1 and ecotope 2, respectively. These results are discussed in the context of insect proximity to human dwellings, the alimentary profile of Mepraia sp., T. cruzi lineages detected in the past in the same diseaseendemic area circulating in humans, and Triatoma infestans.

We prove a stronger version of the Kontsevich Formality Theorem for orientable manifolds, relating the Batalin-Vilkovisky (BV) algebra of multivector fields and the homotopy BV algebra of multidifferential operators of the manifold.

In this study, we performed a phylogenetic analysis of 35 species of the tribe Triatomini by means of available 16S ribosomal DNA and cytochrome b (Cyt b) gene sequence data, adding taxa of the spinolai complex, to clarify phylogenetic relationships of this complex and related triatomines. The phylogenetic analysis suggests a monophyletic clustering of the spinolai complex related to the South American species of triatomines.