Trypanosoma cruzi Flashcards
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
Disease by T. cruzi
American Trypanosomiasis,
Chagas Disease
Vector/s by T. cruzi
Reduviid bugs
Triatoma
Panstrongylus
Rhodnius
Infective Stage by T. cruzi
Metacyclic trypomastigote
Diagnostic Stage by T. cruzi
– Blood smear:_____
– Tissues:______
Trypomastigote
Amastigote
Multiplication: T. cruzi (HA;VE)
– Human: Binary Fission as______
– Vector: Longitudinal fission as_____
amastigote
epimastigote
Reservoir Host of T. cruzi
Domestic animals
armadillo
racoons
rodents
marsupials
some primates
Infection of T. cruzi: intracellular
– Common:
– Others:
myocytes, cells of reticuloendothelial system
skin, gonads, intestinal mucosa, placenta, esophagus
• 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
4
3
Triatoma CN
Triatomine/Kissing Bug, Reduviid Bug
Forms in the Life Cycle of Trypanosoma cruzi
• Amastigote
• Epimastigote
• Trypomastigote
T. cruzi stages in Human
Trypomastigote
Amastigote
Forms of T. cruzi
Vector
• Midgut:
Trypomastigote ->_______
• Hindgut:______
epimastigote
Metacyclic trypomastigote
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
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
T. cruzi
Amastigote
• No exterior flagellum and undulating membrane
-– movement ->______
• Found in_____ and _____ (skin, gonads, intestine mucosa)
rotation
macrophages and MYOCARDIUM
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»_space;> 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
- Concentration Method: Microhematocrit
- 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
