Trypanosoma cruzi (Kinetoplastida Trypanosomatidae): ecology of the transmission cycle in the wild environment of the Andean valley of Cochabamba, Bolivia

An active Trypanosoma cruzi transmission cycle maintained by wild rodents in the Andean valleys of Cochabamba Bolivia is described. Wild and domestic Triatoma infestans with 60% infection with T. cruzi were found and was evidenced in 47.5% (rodents) and 26.7% (marsupial) by parasitological and/or serologycal methods. Phyllotis ocilae and the marsupial species Thylamys elegans, are the most important reservoirs followed by Bolomys lactens and Akodon boliviensis. In spite of both genotypes (TCI and TCII) being prevalent in Bolivia, in our study area only T. cruzi I is being transmitted. Our data suggest that wild T. infestans and wild small mammals play an important role in the maintenance of the transmission cycle of T. cruzi. Furthermore, the finding of high prevalence of T. cruzi infection in wild T. infestans point to the risk of the dispersion of Chagas' disease.     

Reactions of Low Valent Transition Metal Complexes with Hydrogen Peroxide. Are they “Fenton-Like” or not? 4. The Case of Fe(II)L,L = Edta; Hedta and Tcma

The question whether hydroxyl free radicals are formed in the reactions of divalent iron complexes Fe(II)L; L = edta; hedta; tcma (tcma = l-acetato-l,4,7-triazacyclononane) with hydrogen peroxide in neutral and slightly acidic solutions was studied by using the β elimination reaction as an assay for the formation of hydroxyl free radicals, OH. The results show that at pH<5.5 the iron(II)peroxide intermediate complex decomposes rapidly to yield free hydroxyl radicals for L=edta and hedta. This is in contrast to the mechanism of the corresponding Fe(II)nta peroxide complex, which probably decomposes to form Fe(IV)nta which then reacts with organic substrates to yield aliphatic free radicals. Thus, the non-participating ligand L has an appreciable effect on the mechanism of reaction of the metal center with hydrogen peroxide. Blank experiments using ionizing radiation as the source of CH₂CR(CH₃)OH, R = H or CH₃ radicals indicate that when L = tcma intermediates of the type LFe^III-CH₂CR(CH₃)OH_aq are formed, but their major mode of decomposition is not the β elimination reaction. Thus, the present assay for the formation of hydroxyl free radicals by the Fenton Reaction does not fit the latter system.