Epidemiology, pathogenesis, and prevention of African trypanosomiasis
- Sanjeev Krishna, MA, BMChB, DPhil, FRCP, ScD, FMedSci
Sanjeev Krishna, MA, BMChB, DPhil, FRCP, ScD, FMedSci
- St. George's, University of London
- August Stich, MD, MSc, DTMH
August Stich, MD, MSc, DTMH
- Department of Tropical Medicine, Medical Mission Hospital, Würzburg
Human African trypanosomiasis (HAT), also known as sleeping sickness, is caused by protozoan parasites transmitted via the bite of a tsetse fly [1,2]. There are two forms of the disease: an acute form occurring mainly in East Africa and caused by Trypanosoma brucei rhodesiense and a more chronic form occurring mainly in West and Central Africa, caused by Trypanosoma brucei gambiense (table 1) [3,4]. These two species have identical morphologic appearances and both are transmitted by tsetse flies of the genus Glossina. However, the clinical features of infection differ in presentation and prognosis [4,5].
Other Trypanosoma species include T. brucei subspecies brucei, T. lewisi, T. congolense, and T. evansi [5-11] Serum resistance factors lyse animal trypanosomes (including Trypanosoma evansi) and prevent infection in humans, unless there is a host genetic deficiency for these factors .
The epidemiology, lifecycle, and prevention of African trypanosomiasis will be reviewed here. The clinical manifestations, diagnosis, and treatment of these infections are discussed separately. (See "Clinical manifestations, diagnosis, and treatment of African trypanosomiasis".)
There are two forms of human African trypanosomiasis (HAT): an acute form occurring mainly in East Africa and caused by Trypanosoma brucei rhodesiense and a more chronic form occurring mainly in West and Central Africa caused by Trypanosoma brucei gambiense . T. b. gambiense generally causes endemic disease with chronic manifestations (the mean duration of the meningoencephalitic stage is approximately 250 days ), while T. b. rhodesiense is an acute epidemic disease (table 2).
In the last century, there have been three severe epidemics of African trypanosomiasis: one between 1896 and 1906, mostly in Uganda and the Congo Basin; one in the 1920s in several Central African countries; and one that began in 1970, which is abating. The 1920s epidemic was arrested using mobile teams that systematically screened millions of at-risk individuals. The disease practically disappeared between 1960 and 1965, and, subsequently, surveillance was relaxed. Civil wars, displacement of people, economic difficulties, and slackening in vector control measures subsequently allowed reemergence of disease in several foci.To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:
- Kennedy PG. Human African trypanosomiasis of the CNS: current issues and challenges. J Clin Invest 2004; 113:496.
- Büscher P, Cecchi G, Jamonneau V, Priotto G. Human African trypanosomiasis. Lancet 2017.
- Barrett MP, Burchmore RJ, Stich A, et al. The trypanosomiases. Lancet 2003; 362:1469.
- Urech K, Neumayr A, Blum J. Sleeping sickness in travelers - do they really sleep? PLoS Negl Trop Dis 2011; 5:e1358.
- Berriman M, Ghedin E, Hertz-Fowler C, et al. The genome of the African trypanosome Trypanosoma brucei. Science 2005; 309:416.
- Pays E, Vanhollebeke B. Human innate immunity against African trypanosomes. Curr Opin Immunol 2009; 21:493.
- Truc P, Büscher P, Cuny G, et al. Atypical human infections by animal trypanosomes. PLoS Negl Trop Dis 2013; 7:e2256.
- Lun ZR, Wen YZ, Uzureau P, et al. Resistance to normal human serum reveals Trypanosoma lewisi as an underestimated human pathogen. Mol Biochem Parasitol 2015; 199:58.
- Van Vinh Chau N, Buu Chau L, Desquesnes M, et al. A Clinical and Epidemiological Investigation of the First Reported Human Infection With the Zoonotic Parasite Trypanosoma evansi in Southeast Asia. Clin Infect Dis 2016; 62:1002.
- Lin RH, Lai DH, Zheng LL, et al. Analysis of the mitochondrial maxicircle of Trypanosoma lewisi, a neglected human pathogen. Parasit Vectors 2015; 8:665.
- Shegokar VR, Powar RM, Joshi PP, et al. Short report: Human trypanosomiasis caused by Trypanosoma evansi in a village in India: preliminary serologic survey of the local population. Am J Trop Med Hyg 2006; 75:869.
- Checchi F, Funk S, Chandramohan D, et al. Updated estimate of the duration of the meningo-encephalitic stage in gambiense human African trypanosomiasis. BMC Res Notes 2015; 8:292.
- Franco JR, Simarro PP, Diarra A, Jannin JG. Epidemiology of human African trypanosomiasis. Clin Epidemiol 2014; 6:257.
- Simarro PP, Cecchi G, Paone M, et al. The Atlas of human African trypanosomiasis: a contribution to global mapping of neglected tropical diseases. Int J Health Geogr 2010; 9:57.
- Simarro PP, Cecchi G, Franco JR, et al. Monitoring the Progress towards the Elimination of Gambiense Human African Trypanosomiasis. PLoS Negl Trop Dis 2015; 9:e0003785.
- Pepin J. Combination therapy for sleeping sickness: a wake-up call. J Infect Dis 2007; 195:311.
- Smith DH, Pepin J, Stich AH. Human African trypanosomiasis: an emerging public health crisis. Br Med Bull 1998; 54:341.
- Mhlanga JD. Sleeping sickness: perspectives in African trypanosomiasis. Sci Prog 1996; 79 ( Pt 3):183.
- Stich A, Abel PM, Krishna S. Human African trypanosomiasis. BMJ 2002; 325:203.
- Barrett MP. The rise and fall of sleeping sickness. Lancet 2006; 367:1377.
- Control and surveillance of African trypanosomiasis. Report of a WHO Expert Committee. World Health Organ Tech Rep Ser 1998; 881:I.
- Welburn SC, Odiit M. Recent developments in human African trypanosomiasis. Curr Opin Infect Dis 2002; 15:477.
- Cattand P, Jannin J, Lucas P. Sleeping sickness surveillance: an essential step towards elimination. Trop Med Int Health 2001; 6:348.
- World Health Organization. Human African trypanosomiasis (sleeping sickness). Fact sheet 259. 2012. Available at: http://www.who.int/mediacentre/factsheets/fs259/en/ (Accessed on May 29, 2012).
- http://www.who.int/mediacentre/factsheets/fs259/en/ (Accessed on July 06, 2012).
- Migchelsen SJ, Büscher P, Hoepelman AI, et al. Human African trypanosomiasis: a review of non-endemic cases in the past 20 years. Int J Infect Dis 2011; 15:e517.
- Sinha A, Grace C, Alston WK, et al. African trypanosomiasis in two travelers from the United States. Clin Infect Dis 1999; 29:840.
- Ripamonti D, Massari M, Arici C, et al. African sleeping sickness in tourists returning from Tanzania: the first 2 Italian cases from a small outbreak among European travelers. Clin Infect Dis 2002; 34:E18.
- Moore DA, Edwards M, Escombe R, et al. African trypanosomiasis in travelers returning to the United Kingdom. Emerg Infect Dis 2002; 8:74.
- Jelinek T, Bisoffi Z, Bonazzi L, et al. Cluster of African trypanosomiasis in travelers to Tanzanian national parks. Emerg Infect Dis 2002; 8:634.
- Malvy D, Chappuis F. Sleeping sickness. Clin Microbiol Infect 2011; 17:986.
- Lindner AK, Priotto G. The unknown risk of vertical transmission in sleeping sickness--a literature review. PLoS Negl Trop Dis 2010; 4:e783.
- Simon F, Mura M, Pagès F, et al. Urban transmission of human African trypanosomiasis, Gabon. Emerg Infect Dis 2012; 18:165.
- Pepin J, Donelson JE. African Trypanosomiasis (Sleeping Sickness). In: Tropical Infectious Diseases: Principles, Pathogens and Practice, 3rd ed, Guerrant R, Walker DH, Weller PF (Eds), Saunders Elsevier, Philadelphia 2011. p.682.
- Vanhamme L, Paturiaux-Hanocq F, Poelvoorde P, et al. Apolipoprotein L-I is the trypanosome lytic factor of human serum. Nature 2003; 422:83.
- Pérez-Morga D, Vanhollebeke B, Paturiaux-Hanocq F, et al. Apolipoprotein L-I promotes trypanosome lysis by forming pores in lysosomal membranes. Science 2005; 309:469.
- Vanhollebeke B, Truc P, Poelvoorde P, et al. Human Trypanosoma evansi infection linked to a lack of apolipoprotein L-I. N Engl J Med 2006; 355:2752.
- Hajduk SL. Antigenic variation during the developmental cycle of Trypanosoma brucei. J Protozool 1984; 31:41.
- Borst P, Rudenko G. Antigenic variation in African trypanosomes. Science 1994; 264:1872.
- Donelson JE. Antigenic variation and the African trypanosome genome. Acta Trop 2003; 85:391.
- Donelson JE, Hill KL, El-Sayed NM. Multiple mechanisms of immune evasion by African trypanosomes. Mol Biochem Parasitol 1998; 91:51.
- Truc P, Ravel S, Jamonneau V, et al. Genetic variability within Trypanosoma brucei gambiense: evidence for the circulation of different genotypes in human African trypanosomiasis patients in Côte d'Ivoire. Trans R Soc Trop Med Hyg 2002; 96:52.
- Pentreath VW, Kennedy PG. Pathogenesis of human African trypanosomiasis. In: The Trypanomiases, Mudlin I, Holmes PH, Miles MA (Eds), CABI Publishing, Reading, UK 2004.
- Chimelli L, Scaravilli F. Trypanosomiasis. Brain Pathol 1997; 7:599.
- Khonde N, Pépin J, Niyonsenga T, et al. Epidemiological evidence for immunity following Trypanosoma brucei gambiense sleeping sickness. Trans R Soc Trop Med Hyg 1995; 89:607.
- Vreysen MJ. Principles of area-wide integrated tsetse fly control using the sterile insect technique. Med Trop (Mars) 2001; 61:397.
- Kabayo JP. Aiming to eliminate tsetse from Africa. Trends Parasitol 2002; 18:473.
- Hursey BS. The programme against African trypanosomiasis: aims, objectives and achievements. Trends Parasitol 2001; 17:2.
- Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC). Available at: http://au.int/en/dp/rea/RO/PATTEC (Accessed on May 29, 2012).
- Simarro PP, Diarra A, Ruiz Postigo JA, et al. The human African trypanosomiasis control and surveillance programme of the World Health Organization 2000-2009: the way forward. PLoS Negl Trop Dis 2011; 5:e1007.