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Kenya was certified by the World Health Organization (WHO) on August 8, 2025 as having eliminated Human African Trypanosomiasis (HAT), also known as African sleeping sickness, as a public health problem. Kenya is now the 10th country, along with Benin, Chad, Côte d’Ivoire, Equatorial Guinea, Ghana, Guinea, Rwanda, Togo and Uganda, to have eliminated HAT as a public health problem. After the eradication of Guinea-worm disease, this milestone marks a significant public health victory against neglected tropical diseases in Kenya. During the 20th century, HAT triggered severe epidemics in Sub-Saharan Africa. Over the past 25 years, however, sustained and coordinated control efforts have reduced reported cases to record lows, with fewer than 1,000 cases documented globally.
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The disease
African sleeping sickness is caused by protozoan parasites belonging to the Trypanosoma brucei species, transmitted through the bite of infected tsetse flies of the genus Glossina. There are two main forms of the disease: T. b. gambiense, found in West and Central Africa, progresses slowly and accounts for 92% of cases, while T. b. rhodesiense, found in east and southern Africa, is less common but more severe, often progressing rapidly. The disease occurs only in sub-Saharan Africa, in regions where the tsetse fly is found. Cases outside Africa are extremely rare and usually imported by travellers or migrants.
American trypanosomiasis, or Chagas disease, is found primarily in Latin America. It is caused by a different subgenus of Trypanosoma, transmitted by a different insect vector. It has distinct disease features from those of human African trypanosomiasis.
Symptoms and transmission
Human African trypanosomiasis is transmitted mainly through the bite of infected tsetse flies. Other, less common routes include transmission from mother to child during pregnancy when trypanosomes cross the placenta, occasional mechanical transmission by other blood-sucking insects with minimal epidemiological significance, accidental laboratory infections from needle-stick injuries, and, in one reported instance, sexual transmission. Infection occurs during activities such as farming, fishing, hunting, or collecting water or firewood, which bring people into contact with tsetse flies. While individuals of all ages and both sexes are susceptible, the disease is more commonly seen in adults than in children.
When an infected tsetse fly (male or female) bites a person, the parasite multiplies in the blood and lymph, leading to non-specific symptoms such as fever, headaches, weakness, muscle and joint pain, and swollen lymph nodes. This marks the first, or haemolymphatic, stage of the disease. Some individuals may remain without obvious symptoms at first, but over time the parasite can cross the blood–brain barrier and invade the central nervous system, initiating the second, or meningoencephalitic, stage. Once the brain is affected, a range of neurological problems can occur, including disturbances in sleep patterns, profound sensory changes, altered muscle tone, coordination difficulties, psychiatric symptoms, seizures, coma, and eventually death. Without treatment, the disease is almost always fatal.
Diagnosis and treatment
Diagnosis of human African trypanosomiasis typically follows three steps: initial screening for possible infection through serological tests are available only for T. b. gambiense and clinical examination; confirmation by detecting the parasite microscopically in body fluids; and, when necessary, staging the disease by clinical assessment and analysis of cerebrospinal fluid obtained via lumbar puncture. Early detection is crucial to prevent progression to the neurological stage, which requires more complex and risky treatment. Because the first stage of gambiense HAT can be long and relatively symptom-free, active screening of at-risk populations is carried out to identify cases early and eliminate them as a source of infection. Currently, treatment for gambiense HAT uses four main medicines: Fexinidazole, eflornithine, melarsoprol, nifurtimox, and pentamidine, while rhodesiense HAT is treated with melarsoprol, pentamidine, and suramin. Manufacturers provide these drugs as donations and distribute them free of charge by the WHO to guarantee that every HAT patient worldwide can access the most effective treatment.
Kenya’s success
Kenya has maintained steady control measures, with no locally acquired cases reported in over a decade. The last indigenous case was identified in 2009, and the most recent two exported cases, both contracted in the Masai Mara National Reserve, were recorded in 2012. The government, through national programmes such as the Kenya Tsetse and Trypanosomiasis Eradication Council (KENTTEC), implemented targeted surveillance in historically endemic regions like the Lambwe Valley, coupled with vector control measures, public health education, and prompt treatment of detected cases. Despite progress, certain populations across sub-Saharan Africa remain vulnerable. Rural communities in or near tsetse fly habitats, especially those with limited access to healthcare, continue to face the risk of infection. Cross-border populations in endemic areas are particularly susceptible, as movement between countries can facilitate the reintroduction of the disease. The existence of animal reservoirs also complicates eradication efforts.
WHO’s certification criteria
In 2017, during its tenth meeting, the Strategic and Technical Advisory Group for Neglected Tropical Diseases set the definition of “elimination of HAT as a public health problem” based on two key targets: reducing the total number of new cases worldwide to fewer than 2,000 by 2020, and achieving a 90% decrease compared to 2004 levels in the total area at risk that reports at least one case per 10,000 people each year. In Kenya’s case, WHO’s independent verification process confirmed that national surveillance systems were strong enough to sustain elimination.
Situation in India
Only a handful of African sleeping sickness cases have been reported in India, mostly isolated, imported events. Case reports are published due to the disease’s extreme rarity and lack of local transmission, highlighting unusual or travel-associated infections. Transmission risk within India is considered extremely low, as tsetse flies, responsible for the typical human-transmitting species, are not present, and these isolated cases were related to zoonotic spillovers.
Published – September 06, 2025 04:02 pm IST
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