Human African Trypanosomiasis: a Critical Review
Human African Trypanosomiasis: A Critical Review
Introduction
Human African Trypanosomiasis (HAT) or more commonly known as African sleeping sickness is an endemic that is responsible for posing a risk to 60 million people in 36 countries in sub-Saharan Africa( Fig 1) (Brun et al 2009). It is a vector- borne disease which is transmitted by the bite of Tsetse flies of the Glossina genus which injects the protozoan parasite of the genus trypanasoma to humans (Rodgers 2009).
The disease appears to occur in two forms which depend on the subspecies of the parasite involved which include Trypanosoma brucie (T.b) gambiense and Trypanosoma brucie (T.b) rhodesiense. The former is the more common, accounting to be the cause of more than 90% of reported cases and is seen in the Western and Central Africa. The latter causes less than 10% of the disease and prevails in the East and South Africa (Cattand et al 2001, WHO 2006).
[pic]
Fig 1: Showing distribution of HAT in Sub- Saharan Africa (Brun et al 2009)
After the trypanosomes are injected into the host, the disease is said to be in the first (hemo- lymphatic) stage and as the disease spreads attacking the CNS, it is said to be in the second or meningo- encephalitic stage. T.b gambiense causes a chronic infection with the slow invasion of the CNS which lasts for several years without any major clinical signs and symptoms and T.b rhodesiense leads to an acute infection with the fast invasion of the CNS and clinical presentations are observed from a few weeks or months. Both forms are lethal without any treatment (Cattand et al 2001, Lejon et al 2005, WHO 2006).
Clinical manifestations
In terms of the clinical presentations both forms of Trypanosomiasis vary considerably and many symptoms are non- specific, variable and inconstant. With chronic T.b. gambiense the most prominent symptom is gland enlargement mainly in the neck. Other symptoms in the first stage include general malaise, headache, fever,
Introduction
Human African Trypanosomiasis (HAT) or more commonly known as African sleeping sickness is an endemic that is responsible for posing a risk to 60 million people in 36 countries in sub-Saharan Africa( Fig 1) (Brun et al 2009). It is a vector- borne disease which is transmitted by the bite of Tsetse flies of the Glossina genus which injects the protozoan parasite of the genus trypanasoma to humans (Rodgers 2009).
The disease appears to occur in two forms which depend on the subspecies of the parasite involved which include Trypanosoma brucie (T.b) gambiense and Trypanosoma brucie (T.b) rhodesiense. The former is the more common, accounting to be the cause of more than 90% of reported cases and is seen in the Western and Central Africa. The latter causes less than 10% of the disease and prevails in the East and South Africa (Cattand et al 2001, WHO 2006).
[pic]
Fig 1: Showing distribution of HAT in Sub- Saharan Africa (Brun et al 2009)
After the trypanosomes are injected into the host, the disease is said to be in the first (hemo- lymphatic) stage and as the disease spreads attacking the CNS, it is said to be in the second or meningo- encephalitic stage. T.b gambiense causes a chronic infection with the slow invasion of the CNS which lasts for several years without any major clinical signs and symptoms and T.b rhodesiense leads to an acute infection with the fast invasion of the CNS and clinical presentations are observed from a few weeks or months. Both forms are lethal without any treatment (Cattand et al 2001, Lejon et al 2005, WHO 2006).
Clinical manifestations
In terms of the clinical presentations both forms of Trypanosomiasis vary considerably and many symptoms are non- specific, variable and inconstant. With chronic T.b. gambiense the most prominent symptom is gland enlargement mainly in the neck. Other symptoms in the first stage include general malaise, headache, fever,
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