• The World Health Organisation (WHO) has validated Kenya as having eliminated Human African Trypanosomiasis (HAT) or “sleeping sickness” as a public health problem.

• As the name indicates, HAT is transmitted only on the African continent.

• Kenya became the tenth country to reach this important milestone. 

• The other countries that have reached this milestone are Benin, Chad, Ivory Coast, Equatorial Guinea, Ghana, Guinea, Rwanda, Togo and Uganda.

• HAT is the second neglected tropical disease (NTD) to be eliminated in Kenya. The country was certified free of Guinea worm disease in 2018.

• The first cases of HAT in Kenya were detected in the early 20th century. Since then, Kenya has engaged in consistent control activities, without indigenous new cases reported for over 10 years. 

• The last autochthonous case was detected in 2009, and the last two exported cases, infected in the Masai Mara National Reserve, were detected in 2012.

Human African Trypanosomiasis (sleeping sickness)

• Human African Trypanosomiasis (HAT), also known as sleeping sickness, is a vector-borne parasitic disease caused by the Trypanosoma parasite. 

• These parasites are passed to humans through the bite of infected tsetse flies, which get the infection from humans or animals carrying the parasites. 

• This life-threatening disease mostly affects poor rural populations, causing significant harm. Travellers to endemic regions may also be at risk of infection.

• Most exposed people live in rural areas and depend on agriculture, fishing, animal husbandry or hunting.

There are two forms of the disease: 

i) One is caused by Trypanosoma brucei gambiense, found in 24 countries in West and Central Africa, accounting for more than 92 per cent of cases. 

ii) There is another form of HAT caused by Trypanosoma brucei rhodesiense, found in 13 countries in East and Southern Africa accounting for the remaining cases.

• The rhodesiense form (r-HAT), which is found in eastern and southern Africa, was the only one present in Kenya. It is caused by Trypanosoma brucei rhodesiense and progresses rapidly, invading multiple organs including the brain. Without treatment, it is fatal within weeks.

• Sleeping sickness can cause flu-like symptoms initially but eventually causing behaviour change, confusion, sleep cycle disturbances or even coma, often leading to death. 

• Improved access to early diagnosis and treatment, as well as surveillance and response has proven that countries can control and eventually eliminate transmission. 

• In 1995, about 25,000 cases were detected, 300,000 undetected cases were estimated and 60 million people were estimated to be at risk of HAT infection. 

• In 2001, WHO launched an initiative to reinforce control and surveillance, and HAT decreased markedly in the ensuing years. Since 2019, fewer than 1,000 cases have been reported yearly. 

Symptoms:

• After infection, trypanosomes multiply in the blood and lymph (first-stage, haemolymphatic) and, following a variable incubation period (from days to months), unspecific symptoms and signs such as headache, fever, weakness, joint pain, and lymphadenopathy appear. 

• Over time, the parasites cross the blood–brain barrier to invade the central nervous system (second-stage, meningoencephalitic), causing various neurological disturbances including sleep disorders (excessive daytime sleepiness, nocturnal insomnia), deep sensory disturbances, abnormal movements, tremor, ataxia, walking difficulties, speech difficulties, psychiatric disorders, seizures, coma and ultimately death. 

• Sleep cycle disturbance, which gives the disease its name, is a prominent feature. 

• Most signs and symptoms are common to both stages, and sleep disorders in particular can appear already during the first stage.

• Rhodesiense HAT is typically acute, progressing to second-stage within a few weeks, and to death within six months. 

• Gambiense HAT progresses slowly over around three years (highly variable).

Treatment

• Without treatment, HAT is usually fatal although rare cases of self-cure have been reported.

• Available treatment can cure most patients, completely eliminating trypanosomes from the body.

• Treatment of cases suspected by serology depends on specific conditions set by national protocols, which usually set specific conditions defining a higher suspicion index.

• The current treatment options include six medicines, all of which are donated by the manufacturers. WHO ensures their worldwide distribution free of charge.

• Treatment choices are based on the causative trypanosome and the disease stage.

Manorama Yearbook app is now available on Google Play Store and iOS App Store