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African Trypanosomiasis
African Sleeping Sickness
Kristen 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