Human African trypanosomiasis (HAT) can be acquired only in sub-Saharan Africa. About 55 million people are at risk of infection in 36 sub-Saharan countries.[2]Franco JR, Cecchi G, Paone M, et al. The elimination of human African trypanosomiasis: achievements in relation to WHO road map targets for 2020. PLoS Negl Trop Dis. 2022 Jan;16(1):e0010047.
https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0010047
http://www.ncbi.nlm.nih.gov/pubmed/35041668?tool=bestpractice.com
The disease is limited to foci, and about 300 foci have been described.[3]World Health Organization. Report of a WHO meeting on elimination of African trypanosomiasis (Trypanosoma brucei gambiense). December 2012 [internet publication].
http://apps.who.int/iris/bitstream/10665/79689/1/WHO_HTM_NTD_IDM_2013.4_eng.pdf
Most infections (97%) are due to Trypanosoma brucei gambiense. Control efforts have reduced the number of new cases reported. In 2023, 675 cases were reported (down from 2184 in 2016, and 9875 in 2009).[4]World Health Organization: The Global Health Observatory. Indicators: number of reported cases of human African trypanosomiasis (T.b. gambiense). 2024 [internet publication].
https://www.who.int/data/gho/data/indicators/indicator-details/GHO/hat-tb-gambiense
The vast majority of cases are reported in the Democratic Republic of the Congo. Since 2010, the following countries have reported cases of gambiense HAT to the World Health Organization (WHO): Angola, Burkina Faso, Cameroon, Central African Republic, Chad, Congo, Côte d'Ivoire, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Ghana, Guinea, Nigeria, South Sudan, and Uganda.[4]World Health Organization: The Global Health Observatory. Indicators: number of reported cases of human African trypanosomiasis (T.b. gambiense). 2024 [internet publication].
https://www.who.int/data/gho/data/indicators/indicator-details/GHO/hat-tb-gambiense
Cases due to T b rhodesiense are uncommon. In 2023, 24 cases were reported. Most cases occur in Malawi.[5]World Health Organization: The Global Health Observatory. Indicators: number of new reported cases of human African trypanosomiasis (T.b. rhodesiense). 2024 [internet publication].
https://www.who.int/data/gho/data/indicators/indicator-details/GHO/number-of-new-reported-cases-of-human-african-trypanosomiasis-(t-b-rhodesiense)
Since 2010, cases of rhodesiense trypanosomiasis have been reported to the WHO in the additional following countries: Ethiopia, Kenya, Uganda, United Republic of Tanzania, Zambia, and Zimbabwe.
In non-endemic countries, an average of five cases of HAT are diagnosed each year.[6]Franco JR, Cecchi G, Priotto G, et al. Human African trypanosomiasis cases diagnosed in non-endemic countries (2011-2020). PLoS Negl Trop Dis. 2022 Nov;16(11):e0010885.
https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0010885
http://www.ncbi.nlm.nih.gov/pubmed/36342910?tool=bestpractice.com
The majority of these are caused by T b rhodesiense infection and are among travellers or migrants who have visited or resided in rural areas of disease-endemic countries. People diagnosed with T b gambiense infection in non-endemic countries are typically migrants who have originated from or visited an endemic country.
HAT has no particular predominance in sex, age, or ethnicity as infection is related to activities that facilitate contact with the vector. Disease onset is more acute in individuals who do not originate from endemic countries.[7]Duggan AJ, Hutchinson MP. Sleeping sickness in Europeans: a review of 109 cases. J Trop Med Hyg. 1966 Jun;69(6):124-31.
http://www.ncbi.nlm.nih.gov/pubmed/5940665?tool=bestpractice.com