Swallowing air and belching are natural occurrences that result from eating or drinking too quickly. Chewing gum or drinking carbonated beverages can also introduce air into the stomach and cause belching. Because infants frequently swallow air when feeding, burping or belching is normal after they have been fed. The act of burping an infant helps relieve the discomfort caused by swallowed air.
Sleeping sickness, also known as Human African Trypanosomiasis (HAT), is caused by Trypanosoma brucei rhodensiense in Eastern Africa and Trypanosoma brucei gambiense in Western Africa . Both protozoan species are morphologically indistinguishable, but have drastically different epidemiological features.
Trypanosomes are also found in the Americas in the form of Trypanosoma cruzi, which causes American human trypanosomiasis, or Chagas' disease. This disease is found in humans in two forms: as an amastigote in the cells, and as a trymastigote in the blood. The vectors for Trypanosoma cruzi include members of the order Hemiptera, such as assassin flies, which ingest the amastigote or trymastigote and carry them to animals or humans.