Trypanosoma brucei

Trypanosoma brucei is a vector-borne parasitic protozoan responsible for African trypanosomiasis or African sleeping sickness, as it is commonly known. The parasite is transmitted by the bite of the tsetse fly. This name is given after the abnormal fatigue that patients exhibit as T. brucei invades their central nervous system .

Symptoms

The symptoms can be divided into two stages.

In the first stage, Winterbottom’s sign is the first symptom of African trypanosomiasis . Winterbottom's sign is the swelling of the lymph nodes located on the back of the neck (posterior cervical lymphadenopathy) . This is usually followed by fever, myalgia and joint pain (arthralgia).

In the second stage of the disease, referred to as the neurological stage, T. brucei crosses the blood-brain barrier and infects the CNS which leads to confusion, lethargy, disturbances of the sleep cycle, coma and eventually death .

Treatment and prevention

The treatment chosen depends on a few factors such as, the stage the disease is in and the diseases progression.

Suramin is usually used in the first stages of trypanosomiasis . This intravenous drug forms a complex with host plasma proteins which, when inside the parasite, inhibits its enzymes leading to a gradual deterioration of the parasite’s organelles . Even though suramin is usually used against trypanosomes it can also cause severe side effects, which, if not controlled by a doctor, may lead to the patient’s death . Side effects include, skin rashes, kidney failure, adrenal insufficiency, haemolytic anaemia and optic atrophy . It has been shown that some individuals may suffer an idiosyncratic reaction which can cause nausea, vomits, seizures and loss of consciousness .

Alternatively, patients may be given pentamidine isethionate instead of suramin . The process by which pentamidine kills trypanosomes is still not entirely understood, however, it is thought that it binds to a high-affinity energy-dependent carrier that interacts with the parasite’s DNA .