hemoflagellates trypanosomaibrahim 2017.pptx

Haemoflagellates
Trypanosomiasis
Dr. Ibrahim Alkhalife

Different stages of Haemoflagellates

Trypanosomiasis
 There are two types of trypanosomiasis that affect humans
 They are divided according to their geographical location:
 African trypanosomiasis (sleeping sickness) is caused
by Trypanosoma brucei parasites in Africa and is transmitted by
the tsetse fly.
 American trypanosomiasis (Chagas disease) is caused
by Trypanosoma cruzi parasites in Latin America and is
transmitted by the ‘kissing’ bugs.

1-African sleeping sickness
Trypanosoma brucei rhodesiense: East Africa,
wild and domestic animal reservoirs
Trypanosoma brucei gambiense: West and
Central Africa, mainly human infection
2-Chaga’s disease (American trypanosomiasis)
Chaga’s disease in Central and South America
Trypanosma cruzi cause Chaga’s disease.

What isAfrican sleeping sickness?
 African trypanosomiasis is a parasitic disease
transmitted by the tsetse fly. It gets its nickname
‘sleeping sickness’ because symptoms can include a
disturbed sleep pattern.
 Infection occurs through the bite of infected tsetse
flies (intermediate host).
Humans, domestic cattle and wild animals are the
main reservoir host for Trypanosoma (definitive host).
 T. gambiense causes a chronic illness.
 T. rhodesiense causes a more acute illness.

Animal reservoir hosts for African sleeping sickness

How is African trypanosomiasis transmitted ?
 Trypanosoma are transmitted from human to human through the
bite of the tsetse fly which is only found in rural parts of Africa.
 However, trypanosomes can also be transmitted from mother to
child as the parasite can cross the placenta? in the blood and
infect the baby while it is still in the womb?.
 Contaminated needles can also contribute to the spread of
trypanosomes, but this is rare.

Trypanosoma life cycle
 The trypanosome parasite is first introduced into the
mammalian host as trypomastigotes when a tsetse fly
takes a blood meal and secretes parasite-filled saliva into
the host’s skin.
 Once in the bloodstream the trypomastigotes multiply in
the blood, lymph or spinal fluid.

African Trypanosomiasis
Life cycle of Trypanosoma
brucei gambiense & T. b. rhodesiense

Pathology and clinical picture
1. Skin stage: A primary reaction occurs at the site of
inoculation of trypomastigotes, chancre which resolve
in 2-3 weeks.
2. Haematolymphatic stage: intermittent fever, headache
and generalized lymphadenopathy mainly in the
cervical and sub occipital region (Winterbottom’
sign), anemia.
3. Central nervous system stage (CNS): This stage begins
when the trypanosome parasites cross from the blood-
brain barrier into the spinal fluid, infecting the CNS
including the brain, result in change in behavior,
confusion, poor coordination, difficulties with speech
and disturbance of sleep (Meningoencephalitis).
(Development of the disease more rapid in Trypanosoma
brucei rhodesiense)

3rd stage CNS: CNS involvement in typical case there is
daytime sleeping, psychological changes, tremors,
convulsions and finally coma without treatment, the
disease is invariably fatal.

Diagnosis ofAfrican trypanosomiasis
 Diagnosis relies on recognition of the trypomastigote
in peripheral blood during fever, sternal bone
marrow, lymph node aspirates and CSF. Motile
organisms may be visible in the buffy coat.
 Serological testing is also common as IF and ELIZA.

AMERICAN TRYPANOSOMIASIS
LIFE CYCLE OF Trypanosoma cruzi

American trypanosomes (Chaga’s disease)
 The parasites produce focal lymphangitis and oedema at
the site of parasites entry (Chagoma) after that parasites
(trypomastigote) enter the blood stream and find there
way, mainly on the face near the eyelids, it produces a
swelling of the eye and temporal region with
conjunctivitis (Romana’s sign), and also find their way
mainly the cardiac muscles cells. The most constant
feature of the cardiac disease is cardiomyopathy, in
severe cases can lead to partial or complete heart block
which may lead to cardiac failure.
 NOTE: Parasite when free in blood stream in form
(trypomastigote), but in the tissue it become in form of
(Amastigote).

American trypanosomiasis (Chaga’s disease)
American trypanosomiasis, is a tropical parasitic disease caused by
the Trypanosoma cruzi. It is spread mostly by insects known
as "kissing bugs.
The human disease occurs in two stages: an acute stage and chronic
stage. In the early stage, symptoms are typically either not present or
mild, and may include fever, swollen lymph nodes, headaches, or
local swelling at the site of the bite (chagoma). The most recognized
marker of acute Chagas disease is called Romaña's sign, which
includes swelling of the eyelids on the side of the face near the bite
wound or where the bug feces were deposited
or accidentally rubbed into the eye.

T. cruzi causes cutaneous stage
(chagoma)

Ocular lesion (Romana’ sign)

American trypanosomes (Chaga’s disease)
 T. cruzi causes a chronic illness with progressive
myocardial damage leading to cardiac arrhythmias and
cardiac dilatation, and gastrointestinal involvement
leading to mega-oesophagus and megacolon. T. cruzi
causes acute illness in children, which is followed by
chronic manifestations later in life.
intracellular amastigotes destroy the intramural neurons
of the autonomic nervous system in the intestine and
heart, leading to megaintestine and heart aneurysms, If
left untreated, Chagas disease can be fatal, in most cases
due to heart muscle damage.

About two-thirds of people with
chronic symptoms have cardiac
damage, including dilated
cardiomyopathy, which causes heart
rhythm abnormalities and may result
in sudden death.
Heart damage due to
American
trypanosomiasis

Diagnosis
 Microscopical examination of Giemsa–stained blood
film.
 Serology: IFAT
 Xenodiagnosis: feeding bugs on a suspected cases.
 PCR used to detect trypomastigotes.

TREATMENT OF TRYPANOSOMIASIS
African trypanosomiasis
For early infection
 pentamidine
 suramin
For late infection
 Diflouromethylornithine- (DFMO)
American trypanosomiasis (Chaga’s disease)
 benznidazole
 Nifurtimox

hemoflagellates trypanosomaibrahim 2017.pptx

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