African trypanosomiasis | |
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Other names | Sleeping sickness, African sleeping sickness |
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Trypanosoma forms in a blood smear | |
Specialty | Infectious disease |
Symptoms | Stage 1: Fevers, headaches, itchiness, joint pains[1] Stage 2: Insomnia, confusion, Ataxia[2][1] |
Usual onset | 1–3 weeks post exposure[2] |
Types | Trypanosoma brucei gambiense (TbG), Trypanosoma brucei rhodesiense (TbR)[3] |
Causes | Trypanosoma brucei spread by tsetse flies[3] |
Diagnostic method | Blood smear, lumbar puncture[2] |
Medication | Fexinidazole, pentamidine, suramin, melarsoprol, eflornithine, nifurtimox[3] |
Prognosis | Fatal without treatment[3] |
Frequency | 977 (2018)[3] |
Deaths | 3,500 (2015)[4] |
African trypanosomiasis is an insect-borne parasitic infection of humans and other animals.[3]
Human African trypanosomiasis (HAT), also known as African sleeping sickness or simply sleeping sickness, is caused by the species Trypanosoma brucei.[3] Humans are infected by two types, Trypanosoma brucei gambiense (TbG) and Trypanosoma brucei rhodesiense (TbR).[3] TbG causes over 92% of reported cases.[1] Both are usually transmitted by the bite of an infected tsetse fly and are most common in rural areas.[3]
Initially, the first stage of the disease is characterized by fevers, headaches, itchiness, and joint pains, beginning one to three weeks after the bite.[1][2] Weeks to months later, the second stage begins with confusion, poor coordination, numbness, and trouble sleeping.[2] Diagnosis is by finding the parasite in a blood smear or in the fluid of a lymph node.[2] A lumbar puncture is often needed to tell the difference between first- and second-stage disease.[2] If the disease is not treated quickly it can lead to death.
Prevention of severe disease involves screening the at-risk population with blood tests for TbG.[3] Treatment is easier when the disease is detected early and before neurological symptoms occur.[3] Treatment of the first stage has been with the medications pentamidine or suramin.[3] Treatment of the second stage has involved eflornithine or a combination of nifurtimox and eflornithine for TbG.[2][3] Fexinidazole is a more recent treatment that can be taken by mouth, for either stage of TbG.[3] While melarsoprol works for both types, it is typically only used for TbR, due to serious side effects.[3] Without treatment, sleeping sickness typically results in death.[3]
The disease occurs regularly in some regions of sub-Saharan Africa with the population at risk being about 70 million in 36 countries.[5] An estimated 11,000 people are currently infected with 2,800 new infections in 2015.[6][1] In 2018 there were 977 new cases.[3] In 2015 it caused around 3,500 deaths, down from 34,000 in 1990.[4][7] More than 80% of these cases are in the Democratic Republic of the Congo.[1] Three major outbreaks have occurred in recent history: one from 1896 to 1906 primarily in Uganda and the Congo Basin, and two in 1920 and 1970, in several African countries.[1] It is classified as a neglected tropical disease.[8] Other animals, such as cows, may carry the disease and become infected in which case it is known as Nagana or animal trypanosomiasis.[1]
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