Flies in Africa, what is African sleeping sickness? What is the tsese fly?
East African and West African African Sleeping Sickness
African trypanosomiasis, also called African sleeping sickness, is a parasitic disease spread by the tsetse fly. Symptoms include fatigue, high fever, headaches, and muscle aches. If the disease is not treated, it can cause death.
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parasitic disease spread by the tsetse fly
African sleeping sickness is caused by microscopic parasites of the species Trypanosoma brucei, which is found only in rural Africa. Currently, many cases go undiagnosed and unreported. Sleeping sickness is curable with medication, but is fatal if left untreated.
There are two types of African sleeping sickness diseases each is named for the region of Africa in which they were found historically.
East African sleeping sickness is caused by the parasite Trypanosoma brucei rhodesiense, which is carried by the tsetse fly. East African sleeping sickness is found in parts of Eastern and Southeastern Africa. More than 95% of cases are reported from Uganda, Tanzania, Malawi, and Zambia.
Individuals can become infected with West African sleeping sickness if they receive a bite from an infected tsetse fly, which is only found in Africa. West African sleeping sickness, also called Gambian sleeping sickness, is caused by a parasite called Trypanosoma brucei gambiense carried by the tsetse fly. In recent years, 7,000-10,000 new cases of West African trypanosomiasis have been reported to the World Health Organization annually.
West African sleeping sickness and East African sleeping sickness Life Cycle
The cycle in the fly takes approximately 3 weeks. During a blood meal on the mammalian host, an infected tsetse fly injects metacyclic trypomastigotes into skin tissue. The parasites enter the lymphatic system and pass into the bloodstream.
Inside the host, they transform into bloodstream trypomastigotes, are carried to other sites throughout the body, reach other blood fluids (e.g., lymph, spinal fluid), and continue the replication by binary fission.
The entire life cycle of African Trypanosomes is represented by extracellular stages. The tsetse fly becomes infected with bloodstream trypomastigotes when taking a blood meal on an infected mammalian host.
In the fly’s midgut, the parasites transform into procyclic trypomastigotes, multiply by binary fission, leave the midgut, and transform into epimastigotes.
The epimastigotes reach the fly’s salivary glands and continue multiplication by binary fission.
The cycle in the fly takes approximately 3 weeks. Humans are the main reservoir for Trypanosoma brucei gambiense, but this species can also be found in animals. Wild game animals are the main reservoir of Trypanosoma brucei rhodesiense.