African Trypanosomiasis

African Sleeping SicknessKristen Sena

Period 2

General Information• Two types: East and West• Infection is caused by the bite of an infected

tsetse fly that are only found in Africa• It is caused by the protist Trypanosoma Brucei• The tsetse fly is only found in rural areas of Africa• If left untreated the victim will lapse into a coma

and eventually death• It is estimated that 500,000 people are currently

infected with this disease• It also can infect the livestock of the rural

population in Africa

History and Transmission

• History: The African Sleeping Sickness has been present in Africa since at least the 14th century and was identified in 1903 by Sir David Bruce on what is now the country of Mail. In 1960 the disease was almost eliminated and then surged back as the health systems began to fail because of political problems and war in Africa

• Methods of transmission: -Mother to child (crosses the placenta) -Laboratories (can be transmitted through organ transplants but this is uncommon) -Blood transfusion -Infected Tsetse fly bite

West vs East Sleeping Sickness• West: Found in Central and West

Africa, rarely carried to America, Symptoms show within a few months to a year, death occurs after several years if not treated, caused by Trypanosoma brucei gambiense

• East: Found in South and East Africa, more easily carried to America than is West, Symptoms show within 1-3 weeks and death occurs after several months if not treated, caused by Trypanosoma brucei rhodesiense

Symptoms

• West and East: chancre sores, fever, severe headaches, irritability, extreme fatigue, swollen lymph nodes, aching muscles and joints, can invade CNS and cause neurological problems including confusion and personality changes, some develop a skin rash, enlarged spleen, and increased heart rate

• Symptoms only found in West: swelling of face and hands, itching skin, weight loss, daytime sleepiness and nighttime disturbances

Tests and Treatment• Tests include a blood sample and sometimes a

spinal tap• Treatment depends on the patients lab results

but it includes the drug Melarsoprol made of an arsenic and anti-freeze compound, but this drug is very dangerous and kills about 15-20% of those treated, another drug that used to be manufactured is eflornithine. The production of this “miracle drug” stopped because of the high cost of manufacturing it, low profit, and the negative effect It had on treating cancer which was its original purpose.

Effect and Potential treatment

• The parasite overcomes the bodies defenses causing anemia, endocrine, cardiac, kidney diseases and disorders. It enters into a neurological state when it passes through the blood-brain-barrier

• Potential treatment: A team of CNRS researchers has found protein within the parasite and without this protein, the protist would not be able to feed itself causing it to die. The researches are trying to find a way to eliminate or prohibit this protein from functioning within the parasite.

The Infection• The parasite lives in the gut of

the fly and travels into the saliva when it bites infecting either a human or animal. The protist lives in the bloodstream of the host but often will travel to other parts of the body after infection.

- The Tsetse fly is found in rural areas and bites during the day light hours. They inhabit forests and thick vegetation along rivers and water holes. The majority of the flies in Africa do not carry this protist.

Cell Structure• Mostly like a eukayotic cell• Unusual features: a single large mitochondria with condensed mitochondria DNA and is associated with the flagellum• The surface of the cell also has a dense coat of

glycoproteins to avoid the immune system of its host. It does this by frequent genetic modification or “switching” allowing a new VSG coat to be created. This way it is constantly avoiding the immune respose that recognizes it and tries to eliminate it by changing the active expression or by changing the VSG gene in the active site. This creates a chronic infection.

Reproduction• The constant switching of its outer protein coat allows

it to be unrecognizable and allows time for reproduction.

• This pathogen undergoes a mitotic process but is different in the cytoskeletal process. -The basal body replicates-The kinetoplast replicates and the two daughter cells are seaerated by the basal bodies-The second flagellum grows and the nucleus replicates-The mitochondria divides and cytokinesis occurs

Effect on the Body• After the fly bites the protist enters

the bloodstream and begins to avoid the bodies immune system by antigenic variation. While this is ocuring it gives the protist a chance to replicate and inhabit other parts of the body. The replicated protists move throughout the body and begin affecting the bodies organs. In advanced cases of this disease the parasite invades the central nervous system and can change the patients behavior and cause other neurological problems