Elemental distribution in Rhodnius prolixus head structures after Azadirachtin treatment by low energy X-ray fluorescence

Full text: In this work, phase-contrast microtomography and X-ray microfluorescence synchrotron techniques were used to study Rhodnius prolixus, a potential vector of Trypanossoma cruzi, the etiologic agent of Chagas disease, which is a serious parasitic disease in Latin America, affecting approximately 8 million people in this region. Vector control is the most powerful method against this disease. Fifth stage specimens of the Rhodnius prolixus were taken from the colony of the Laboratory of Biochemistry and Physiology of Insects (FIOCRUZ, Brazil) and the insects were divided into two groups. The first group was treated with azadirachtin, which is a triterpene that prevents metamorphosis from the insect to the adult stage, and the other was the control group. After sample preparation, microtomography measurements were performed in the SYRMEP beamline, and X-ray microfluorescence measurements in the TwinMic beamline, both in the ELETTRA synchrotron, Trieste, Italy. The main objective of this work was to compare the two groups, in order to find morphological and multi elementary changes between them, using microtomography and microfluorescence synchrotron techniques. The results showed that azadirachtin is a powerful natural pesticide, directly affecting the internal structures of this insect, preventing metamorphosis and, consequently, preventing the proliferation of Chagas disease. (author)