protozoa - flagellates - hemoflagellates Flashcards
where do hemoflagellate live
in the bloodstream and tissues
trypanosomes morphology
elongated, spindle-shaped
flagellum
undulating membrane
single nucleus
kinetoplast
hemoflagellate life stages
-amastigote
-trypomastigote
-promastigote
(not all life stage types are present in all trypanosomes)
what life stages occur in vertebrate hosts
amastigote and trypomastigote
what life stages occur in invertebrate hosts
promastigote
amastigote
non-motile
no visible flagellum
replicates in tissues
trypomastigote
infective form in some species
flagellum
promastigote
infective form in some species
flagellum
trypansomes transmission
-arthropod vector: arthropod bites mammal host and ingests trypomastigote in blood
- salivarian transmission - when insect bites host
- stercorarian transmission - arthropod feces
trypanosoma cruzi host
dogs; all mammals
trypanosoma cruzi morphology
in bloodstream:
-trypomastigotes = spindle-shaped, single flagellum, undulating membrane, nucleus and kinetoplast
in macrophages and cardiac myocytes:
-amastigotes = intracellular, oval-shaped, no flagellum
trypanosoma cruzi reservoir
wild mammals (raccoons, opossums, armadillos)
trypanosoma cruzi source
arthropod vector (triatoma bugs)
trypanosoma cruzi transmission method
stercorarian transmission to dog/mammals or oral ingestion of infected triatoma bugs
trypomastigote invades cardiac myocyte and turns into amastigote and divides then turn back into trypomastigote
infected myocyte ruptures and trypomastigote released into host blood stream
trypanosoma cruzi clincial signs
acute phase:
-within a couple weeks after infection
-cardiac failure (arrhythmias, myocarditis, dilated cardiomyopathy)
- can be fatal
latent phase:
-if host survives acute phase; asymptomatic
chronic phase:
-months after infection
-cardiac failure
trypanosoma cruzi patho
-trypomastigotes invade cardiac myocytes - INTRACELLULAR
-amastigote replication in cells damage the cell
-host immune response –> INFLAMMATION
-progressive cardiac damage
trypanosoma cruzi diagnosis
-clinical signs: heart failure (ECG changes, thoracic imaging)
-cytology: trypomastogtes in stained blood films (acute stage)
-serologic tests: antibody detection (ELISA, IFA)
trypanosoma cruzi treatment/prevention
-drugs are not easily available
-supportive therapy for cardiac disease
-reduce exposure to vectors
trypanosoma cruzi zoonotic?
-not directly to people from mammals
-triatoma bug vector required
-dogs are a possible reservoir for human inf.
Leishmania host
dogs, people
less common - cats, horses, other animals
Leishmania morphology
in mammal host
-in macrophages: amastigotes - oval shaped, no flagellum
-in sand fly vector: promastigoTes - flagellum
Leishmania arthropod vector
sand flies
Leishmania transmission
-salivarian transmission (promastigotes) to dog via sandy fly bite
-promastigote invades macrophages
-promastigote turn into amastigote
-divides, infected macrophage ruptures, amastigotes infect other cells/macrophages
-
Leishmania source
bite of sand fly carrying Leishmania
Leishmania clinical signs
-cutaneous lesions: dermatitis, skin ulceration
-visceral/systemic signs: lymphadenomegaly, weight loss/muscle wasting, lethargy, splenomegaly, GI signs
-immune response leads to –> kidney failure, epistaxis, ocular disease
-may not be seen for months to years following infection
Leishmania patho
-phagocytized by macrophages (as promastigotes)
-multiply in macrophages (as amastigotes)
-disseminate to … hemolymphatic organs and skin
-chronic disease
Leishmania diagnosis
-antibody testing (serology)
-PCR
-visualization of amastigotes: cytology, biopsy
Leishmania treatment
-drugs available (must report infected dog to CDC)
-difficult: months of treatment; rarely eliminated
-relapses common
Leishmania control and prevention
-keep dogs indoor during sandfly season
-prevent sandfly bites (topical insecticides for dogs)
-vaccine (one available)
Leishmania zoonotic?
-nothing documented from dogs to people
-sand fly vector required
-humans can be infected via bite of infected sandfly
