Commentary: The lucid reasoning of Carlos Chagas

chicken blood. In the contaminated areas where we worked, we never found a bug-free hut among the rural population. New houses, built in remote spots far from other dwellings, are very quickly invaded by Conorhinus, despite the difficulty of infestation from another home. In areas where the ‘‘barbeiro’’ is present, recently settled small towns are quickly infested. A case in point is Lassance, a village that came into being with the arrival of the railroad. In the first two years after it was established, infested houses were few and far between. Today, four years later, Conorhinus is found in almost every house of Lassance, and schizotrypanosis is rampant. The bug bites only at night. In the dark, when the lights have been turned off, it leaves its hiding place and crawls down the walls in search of man. Adults can reach beds and mosquito nets in short flights. During the day, Conorhinids do not leave their hiding places. However, if a person leans for some time against a wall, he is sometimes bitten, as happened in our presence to a companion on an excursion to an infested house. We report this as a warning against prolonged contact with the walls of suspect houses. The bug’s bite is almost painless and leaves no betraying mark at the site, nor is it followed by any inflammation whatever. I watched children sleeping undisturbed while about 20 nymphs and adults of Conorhinus sucked blood from their bodies. Conorhinus megistus transmits the disease as a larva, as a nymph, and as a winged insect. A young larva is no larger than a bed bug and can be carried along in laundry, luggage, etc. This fact is very important for prophylaxis, and may account for the appearance of sporadic cases in homes where ‘‘barbeiros’’ are not present. We should also state the possibility of the disease being transported by larvae to other parts of the country when frequent communication has been established with infested regions.