American Trypanosomiasis, or Chagas' disease, is most commonly communicated through kissing bugs (Triatoma protracta). The parasite (Trypanosoma cruzi) will transmit the disease by painlessly biting a human host on the eyes, lips or ears as they sleep. Chagas' disease, a relative of African sleeping sickness, affects mainly the nervous and circulatory systems, especially the heart. The result can range from a weak pulse to loss of motor skills to heart failure. Left untreated, the disease is often fatal, preceded by bouts of dementia.