Sleeping sickness: a “neglected disease“ that can be eliminated
Human African trypanosomiasis (HAT),
also known as sleeping sickness, has for
many years been one of the major neglected
diseases found in the endemic areas of the least
developed countries of sub-Saharan Africa.
The disease affects people in rural areas where
they are in close contact with the tsetse fly
vector. The causative agent of HAT is a
single-celled protozoan parasite belonging to
the genus Trypanosoma, and is transmitted
through the bite of tsetse flies.
 Transmission cycle of trypanosomes that cause sleeping sickness
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Inhabitants of endemic areas are usually poor,
and health systems in such areas are weak
or non-existent, which in turn impairs rapid
diagnosis and effective treatment. People
who depend on agriculture, fishing, animal
husbandry or hunting are the most exposed
to the tsetse bite and therefore to the disease.
Most of the drugs used to treat sleeping sickness are not only toxic but also
difficult to administer, and thus a burden for
the patients.
There are two forms of sleeping sickness,
depending on the sub-species of the infecting
parasite:
Trypanosoma brucei gambiense causes
chronic infection and is found in West and
Central Africa. This form represents more
than 90% of the cases of sleeping sickness
reported. A person can be infected for
months or even years without major signs or
symptoms. Once symptoms emerge, the disease
is often in an advanced stage, meaning
that the patient’s central nervous system
(CNS) is affected.
Trypanosoma b. rhodesiense is found in
eastern and southern Africa. This form of
the disease represents less than 10% of
reported cases and causes an acute infection.
The first signs and symptoms are observed a
few weeks or months after infection. The disease
develops rapidly and parasites quickly
invade the CNS.
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