We studied the rate of dessication of bug faeces at room temperature with different relative humidities and at the mean temperature of the human skin (33°C). The time necessary to evaporate the water present in bugfaeces was inversely proportionalto the atmosphere saturation deficit and was accelerated at higher temperatures. We studied the motility offaecalflagellates on direct microscopy and infectivity ofthe same afterthe introduction of the faeces in the peritoneal cavity of mice. At low humidities, both motility and infectivity were lost within 30 minutes, at high humidities these parameters were preserved up to 30 minutes at 33°C. 100% ofmice were infected after 15 minutes, butonly 3.3% after 30 minutes exposure at this temperature. Ambiental conditions of the interior of a house in Mambai varied greatly over a year of observation. However they were often similar to those of our laboratory experiments.
Dessication; Skin microclimate; Chagas' disease