The disease occurs in two forms:
- East African trypanosomiasis
- West African trypanosomiasis.
- Chagas disease or American trypanosomiasis
Certain regions of Eastern and Central Africa are affected by East African trypanosomiasis especially Botswana, Tanzania, Zaire, Kenya, Malawi,Zimbabwe, Ethiopia, and Uganda .It is caused by the parasite Trypanosoma brucei rhodesiense. It results in an acute form of the disease with the infection in full blown form in a few weeks.
Certain regions of West and Central Africa are affected by West African Trypanosomiasis caused by Trypanosoma brucei gambiense. It causes a chronic condition existing in a passive phase for months or years before symptoms emerge.
Annually, about 20,000 fresh cases of both East and West African trypanosomiasis are reported. The trypanosomiasis also affects animals, causing Animal African Trypanosomiasis (AAT) or Nagana. Trypanosoma brucei brucei is responsible for causing cattle disease.
Chagas disease or American trypanosomiasis
Chagas disease is also called as the American trypanosomiasis which is mainly prevalent in the Americas especially in the poor, rural areas of central and southern America.
Brazilian physician Carlos Chagas was the first person to describe this tropical disease and hence the name. The pathogenic agent causing the disease is a flagellate protozoan named Trypanosoma cruzi. It is transmitted to humans and other mammals commonly by Triatomine bugs which acts as the vector.These bugs are also called 'kissing bugs'.Other routes are ingestion of food contaminated with parasites, blood transfusion, fetal transmission and other infected humans and via domestic animals like cats, dogs, guinea pigs and wild animals like rodents,
The three stages of Chagas disease are as follows:
- The acute stage sets in during the immediate period following the infection.
- The intermediate stage appears after 8-10 weeks of the infection.
- The chronic stage manifests after a silent period. This also leaves a permanent damage to much of the internal organs like the colon, heart and the peripheral nervous system.
- Chagas Disease - (http://www.nlm.nih.gov/medlineplus/chagasdisease.html)