Trypanosoma cruzi Flashcards by Kyra Catedral

Epidemiology

• - Latin America, Central America, South America

•_____ million affected; 10,000-12,000 die annually

• Transmission:

– Majority:______

–(4)

10M

vector borne

Blood transfusion
needle-prick
transplacental
organ transplantation

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Disease by T. cruzi

American Trypanosomiasis,
Chagas Disease

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Vector/s by T. cruzi

Reduviid bugs

Triatoma
Panstrongylus
Rhodnius

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Infective Stage by T. cruzi

Metacyclic trypomastigote

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Diagnostic Stage by T. cruzi

– Blood smear:_____

– Tissues:______

Trypomastigote

Amastigote

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Multiplication: T. cruzi (HA;VE)

– Human: Binary Fission as______

– Vector: Longitudinal fission as_____

amastigote

epimastigote

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Reservoir Host of T. cruzi

Domestic animals
armadillo
racoons
rodents
marsupials
some primates

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Infection of T. cruzi: intracellular

– Common:

– Others:

myocytes, cells of reticuloendothelial system

skin, gonads, intestinal mucosa, placenta, esophagus

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• Dark brown to black with small tan edge around its abdominal region

• Wings are held flat over the back at rest

• Head:
____segmented antennae
____segmented beak that extends backward below the body

Triatoma

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Triatoma CN

Triatomine/Kissing Bug, Reduviid Bug

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Forms in the Life Cycle of Trypanosoma cruzi

• Amastigote

• Epimastigote

• Trypomastigote

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T. cruzi stages in Human

Trypomastigote
Amastigote

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Forms of T. cruzi

Vector

• Midgut:

Trypomastigote ->_______

• Hindgut:______

epimastigote

Metacyclic trypomastigote

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T. cruzi

• Round or ovoid in shape

• 1.5 to 4 um diameter

• In small groups of cystlike collections in tissue

– Intracellular in humans

• Replicating form in human host

Amastigote

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Amastigote in humans

•______ in shape

• 1.5 to 4 um diameter

• In small groups of ____like collections in tissue

– Intracellular in humans

•______ form in human host

Round or ovoid

cyst

Replicating

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T. cruzi

Amastigote

• No exterior flagellum and undulating membrane
-– movement ->______

• Found in_____ and _____ (skin, gonads, intestine mucosa)

rotation

macrophages and MYOCARDIUM

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T. cruzi

Trypomastigote

• NO____ capability

•_____ infective

– Invertebrate vector:____ trypomastigote

– Vertebrate host (human):____ trypomastigote

replicative

Extracellular

metacyclic

blood

T. cruzi

Trypomastigote

Shape: Unique(3)-shaped

C, S or U

• Replicating form in human host

Amastigote

T. cruzi

Trypomastigote

Undulating membrane: narrow with #______ undulations, single threadlike flagellum originating near the prominent kinetoplast

2-3

T. cruzi

Epimastigote

•______ of vector

• Mobile, presenting intense replicative activity by longitudinal binary division

Midgut

T or F

Trypomastigotes don’t multiply in the blood

True

• _______ inside the host -> engulfed by macrophages

• Multiply inside the macrophages as_____ (binary fission)

Metacyclic trypomastigote

amatigotes

• Amastigotes ->________ and are released in 4-5 days

• Released trypomastigotes enter the bloodstream

– ready to replicate once they enter another cell OR

– ingested by the insect vector

Trypomastigotes

• Trypomastigote ingested by vector -> pass through the posterior portion of the midgut ->________ • Epimastigotes multiply through longitudinal binary fission

Epimastigote

• Infective ________ appear in the insect’s rectum -> passed through the feces

metacyclic trypomastigotes

•_______ gain entry into the human host – broken skin – mucous membranes

Trypomastigotes

Pathogenesis:_______ • Focal or diffuse inflammation mainly affecting the ***skin and myocardium*** – ***Non specific symptoms*** such as fever, malaise, nausea, vomiting, and lymphadenopathy – ***Cutaneous manifestations*** are usually seen in the site of inoculation Undetected and undiagnosed in most individuals

Acute Phase

• Furuncle-like lesions associated with induration, central edema and regional lymphadenopathy • Appears on the site of entry of parasite.

Chagoma

• Swelling of the eyelid if the parasite penetrates the ***conjunctiva*** • Unilateral, painless, bipalpebral edema with conjunctivitis, may involve lacrimal gland and lymphadenopathy • Resolves after 12months

Romana’s Sign

Pathogenesis:______ • Maybe ***autoimmune-mediated*** • Fibrotic reactions to the parasite >>> injury to the myocardium, cardiac conducting pathways (SA and AV node) and even in the enteric nervous system

Chronic Phase

Pathogenesis: Chronic Phase ________: primary organ affected – Less severe: Chest pain, palpitation, dizziness, syncopal episodes, abnormal ECG results – Severe: Cardiomegaly, congestive heart failure, arrhythmia, thromboembolism, cardiomyopathy à left ventricular apical aneurysm

Heart

Pathogenesis: Chronic Phase •______: – Chronic constipation with megacolon – Achalasia with megaesophagus

GIT

Diagnosis:______ • Complete patient history – Exposure to the insect vector, travel history – Place of residence and work – Recent blood transfusion in the endemic area • Definitive diagnosis during acute phase – Direct visualization of the parasite in the thick and thin blood smear using ***GIEMSA stain*** – ***Tissue biopsy, CSF and lymph*** can also be submitted

Acute Phase

Other Tests in the Acute Phase

1. Concentration Method: Microhematocrit 2. Xenodiagnosis

– Laboratory reared triatomine bugs are allowed to feed on suspected patients and later (1month after) on examined for the presence of metacyclic trypomastigotes (intestinal contents)

Xenodiagnosis

Diagnosis: Chronic Phase (4) *WHO recommends that at least____ of the tests above should be positive before a diagnosis of Chagas disease should be made

• ELISA • Indirect Hemagglutination • PCR • Indirect Immunofluorescence two

Other Diagnostic Modality • Cardiac Involvement:

ECG Echocardiography

Management • Acute Phase –_______ Adverse effect: weight loss, anorexia and antabuse effect (severe hangover is patient will drink alcohol) –_______ Adverse effect: rash, bone marrow suppression, and peripheral neuropathy •______________: halt (not reverse) progression of cardiomyopathy

Nifurtimox Benznidazole Allopurinol and Itraconazole

Management • Chronic Phase – Symptom-specific management • Cardiac –______: Temporary or Permanent –______ • GIT –__________ –_____

Pacemaker Antiarrhythmic drugs Laxatives and soft diet Surgery