Trypanosoma
spp.
Polymorphic spindle-shaped
Kinetoplast
Flagella & undulating membrane
Trypanosoma
• require more then one host to complete their
life cycle
• transmitted through blood feeding
invertebrates (insects)
• mostly live in blood tissue but can be found in
different locations in the host
• uses antigen variation, or variation of the
protein coat, in order to avoid detection by the
body
• It cause sleeping sickness or
Trypanosomiasis
Trypanosomes
• Salivarian Trypanosomes
• Stercorian Trypanosomes
Human Trypanosomiasis
African Trypanosomiasis
West-Africa: Trypanosoma brucei gambiense
“sleeping sickness”.
East-Africa: Trypanosoma brucei rhodiesiense
American Trypanosomiasis
Trypanosoma cruzi
Trypanosomiasis in Africa
Vector - Tse Tse fly
Trypanosoma brucei gambiense , causes chronic
infection lasting years, and affects countries of western
and central Africa Glossina palpalis (Western Africa)
Trypanosoma brucei rhodesiense , causes acute
illness (much worse) lasting several weeks in southern
and eastern Africa.
Glossina mortisans (Eastern Africa)
How is it Transmitted?
• African sleeping sickness is
transmitted by the tsetse fly, found
only in rural Africa. There are over 22
types of this fly and all scrictly feed on
Blood
• Breed by Rivers and streams
•
• A pregnant woman could pass the
infection to her child and, in theory,
the infection could also be transmitted
by blood transfusion or sexual contact
Millions of square kilometers of
Africa are home to the tsetse fly,
vector of trypanosomiasis:
•
Uganda
Kenya
Tanzania
Malawi
Ethiopia
Zaire
Zimbabwe
Botswana
• 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
Signs & Symptoms
First Stage
• In the first stage the parasite is found in the peripheral
circulation, but has not yet invaded the central nervous
system. hemolymphatic stage
• Symptoms include:
– Headaches
– aching muscles and joints
– Fever
– Swollen lymph nodes all over the body
– Swollen, red, painful nodule at site of fly bite (Primary
chancre) - resolves 2-3 weeks
* The symptoms of both West and East African Sleeping Sickness are
essentially the same
Winterbottom's sign - Swollen
lymph nodes along back of neck in
child with early trypanosomiasis
Chronic Disease Phase
• In the second stage, the parasite crosses the bloodbrain barrier and infects the central nervous system.
Neurological phase
• Symptoms include:
– Confusion
– Personality or mood changes
– Difficulty walking and talking
– Seizures
– Night insomnia
– loss of consciousness and coma
Diagnosis
• Microscopic examination
– chancre fluid
– lymph node aspirates
– Blood
– bone marrow
– cerebrospinal fluid (late stages of infection)
• Serology
• Animal inoculation
Prevention
• Currently there is no vaccine or drug to
prevent infection of African sleeping
sickness.
• This illness is only spread by the bite of a
Tsetse fly, so if possible, the best way to
prevent this illness is to avoid travelling to
Africa.
• Preventative Measures Include:
– Wearing long-sleeved shirts and pants of
medium-weight material in neutral colors.
– Inspecting vehicles for flies before entering.
– Avoiding bushes since tsetse flies are less
active during the hottest parts of the day.
Natural Reservoir Hosts
Thompson’s gazelle
Warthog
Impala
Oryx
Domesticated Reservoir Hosts
Control
Destruction of animal reservoir
Vector Control
Diagnosis & treatment