W2- Phylum Sarcomastigophora. Subphylum Mastigophora Flashcards
What is Phylum Sarcomastigophora?
what are subphylums?
they are free living protozoans.
subphylums:
- Mastigophora/ flagellates–> move using flagella
- Sarcodina/ ameboa–> move by cytoplasmic protrusions called pseudopods
Genus Trypanosoma characteristics
has:
- a single nucleus (round/oval in centre of body),
- a kinetoplast (well developed mitochondrion DNA),
- a single flagella.
- affects humans and animals,
- mostly transmitted by insects.
- size= 14-33µm
- has an undulating membrane(trypomastigote)
What are trypanosomes?
where are the found?
- they are Extracellular hemoflagellates in connective tissue space.
In smear: between RBCs - found in peripheral blood, lymph nodes, spleen + cerebrospinal fluid
What is Trypanosoma Equiperdum?
cause?
It is an animal parasite causing dourine in horses. DOESN’T affect humans.
it is an extracellular parasite living in blood plasma. cell is elongated and spindle-shaped. it is a trypomostigote (kinetoplast is posterior to the nucleus).
Trypanosoma Equiperdum transmission
sexually transmitted in horses
Is Trypanosma Brucei intracellular or extracellular?
what does it cause?
an extracellular parasite, they are in-between RBCs - doesn’t enter cell.
infects humans and animals causing African trypanosomiasis (sleeping disease).
sleeping disturbances, abnormal reflexes, sensory disorders, untreated=death
Trypanosma Brucei transmission
latin name?
transmitted by vectors=tse-tse fly bite. (lat= Glossina)
Trypanosma Brucei forms
trypomastiogote in vertebrate host, epimastigote in the insect vector
What are the types of Trypanosma Brucei?
where are the the types found?
T.B Gambiense: takes years to act, chronic. found in C+ W Africa
T.B Rhodesience; acts in week, acute. found in S+E Africa.
Hemoflagellates morphology
- Amastigote:(Hum) rounded, no flagellum. seen as intracellular form in vertebrate host. Axosome- ant of cell. not mobile
- Promastigote:(Ins) K ant to N, near ant of cell. F at anterior of cell. no UM.
- Epimastigote:(Ins) K post of cell, its ant to N. F runs alongside the body as short undulating membrane then emerges from the ant end
- Trypomastigote:(Hum) spindle shaped w/ central N. Kineto post to N at post end of body. F runs alongside the entire length of the cell + forms a long UM before emerging as a free F from the ant end
Trypanosma Brucei Life cycle
- Tsetse fly injects metacyclic trypomastigotes
- meta..—> long slender trypomastigotes in blood. Reach body fluids
- multiply in fluids- binary fission
- trypomastigotes circulate in blood
- tsetse fly takes blood w/ trypomastigote
- go to midgut-procyclic trypomastigotes. multiply
midgut, leave as epimastigote - epimastogoes go salivary gland of vector.
Epimastigote—> metacyclic Trypomastigotes
Hosts of Trypanosma
Def Host: humans
Inter Host: insect vector (tse-tse or ‘kissing bugs’)
Is trypanosome Cruzi extracellular or intracellular? what does it cause? where?
its extracellular and intracellular parasite.
causes chagas disease
found in C&S America
How is trypanosome Cruzi transmitted/vector? when are they active
transmitted through bite of Triatomine bug (kissing bug)
they feed during the night, feces rubbed into bite wound
Morphology of trypanosome Cruzi
in human host: extracellular trypomastigote in blood AND intracellular amastigotes in tissues
in insect vector: epimastigote
Life cycle of trypanosome Cruzi
- Infected Triatomine bug passes metacyclic trypomastigote in faeces or bite wound
- Metacyclic trypomastigote penetrate through cells and becomes amastigote- loose flagellum
- Amastigote replicate in cell by binary fission and infect cell
- Amastigote–> trypomastigote cell ruptures releasing the trypomastigote into bloodstream
- Triatomine bugs ingest trypomastigotes
- Differentiate to epimastigote in midgut and multiply in midgut.
- Metacyclic trypomastigotes in hind gut
Leishmania Donovani hosts/vector
def host: human,dog &mammals vector: female sandfly (Phlebotominae)
Is Leishmania intracellular or extracellular?
its intracellular (amastigote) parasite in host. its extracellular (promastigote) in sandfly vector
What does Leishmania Donovani cause?
causes visceral leishmaniasis= kala azar (black fever). it infects internal organs (liver, spleen, bone marrow)
Morphology of Leishmania Donovani?
2 forms:
1) amastigote (no flagellum) in humans
2) promastigote(with flagellum) in female sandfly
infective form of trypanosome
metacyclic trypomastigote
Infective form of Leishmania Donovani?
promastigote form in female sandflies midgut
Leishmania Donovani transmission
bite from infected female sandfly.
rarely:
organ transplant, blood transfusion
mother to foetus
Leishmania Donovani lifecycle
- Sandfly injects promastigote stage into skin
- Promastigote is phagocytise by macrophages.turns to amastigote(lose flagellum)
- Amastigotes multiply in cells of tissue + infect other cells
- Sandfly ingests macrophage with amastigote
- Ingest parasitised cell.amastigotes—>promastigote in gut.
- Multiply in gut and migrate to proboscis(mouth)
Leishmania Donovani and phagocytes
phagocytes try to kill Leishmania, but parasite resists killing and takes control of phagocyte obtaining its nutrients and replicating in cytoplasm until cell ruptures
What are parasite reservoirs?
infected parasite, serve as a source of infection for humans. DO NOT experience the symptoms of disease when infected.
What does Leishmania Tropica cause
Causes cutaneous leishmaniasis (oriental sore)- mildest leishmaniasis. Large ulcers on skin.
can heal by itself, but leaves a disfiguring scar.
Trichomonas Vaginalis morphology
size=15-20µm.
pear-shaped as it has an axosome at post end. anterior end is broader- has 5 flagella(4 runs free+ 5th runs backwards supporting the undulating membrane)
Is Trichomonas Vaginalis intracellular or extracellular?
where is it found?
extracellular
inhabits in mucosal surface of vagina+urethra in both sexes. it feeds on bacteria.
How is Trichomonas Vaginalis transmitted?
sexual intercourse
What is cytostome in Trichomonas Vaginalis?
its an invagination used for phagocytosis.
What does Trichomonas Vaginalis cause?
trichomoniasis=STD.
causes inflammation in female genital tract but lives In male w/o any symptoms.
in women can cause vaginitis–discharge + unpleasant odour.
Trichomonas Vaginalis life cycle
- trophozoite in vaginal and prostatic secretions and urine
- Multiplies by longitudinal binary fission
- Sexual intercourse—>trophozoites in vagina /opening of vagina
Trichomonas Vaginalis forms
ONLY trophozoite, no cyst form
Where is Giardia lamblia found?
found in the SI- duodenum and jejunum.
they absorb nutrients.
Giardia lamblia forms
2 forms:
1) Trophozoite
2) cyst
Giardia lamblia trophozoite morphology
size=15x9µm
heart-shaped, its rounded ant and pointed post. has bilateral symmetry.
-ant part has: 2 nucleus
-post part has: 8 flagella
there is a sucking disk used for attachment to intestinal mucosa.
it has an axostyle running midline
Giardia lamblia cyst morphology
size= 12x8µm
small, oval, surrounded by thick cyst wall
it has 4 nuclei due to mitosis w/o cytokinesis.
flagella are internalised inside cytoplasm
What is the infective form of Giardia lamblia
the mature cyst
Giardia lamblia transmission
ingestion of cysts in contaminated f/w.
fecal-oral route
Giardia lamblia life cycle
- Cyst is ingested- contaminated f/w. fecal-oral route
- excystation in duodenum, releases trophozoites. 1 cyst=2 trophozoites.they multiply by binary fission and remain attached to duodenal mucosa by ventral sucking disk.
- Encystation occurs as parasites go towards colon. cyst formed
- cysts are excreted in feces
What is the other name for Giardia lamblia
Lamblia intestinalis
What does Giardia lamblia cause
Causes giardiasis - infection of SI
Is Giardia lamblia intracellular or extracellular?
Extracellular
how do Trypanosoma escape the Immune system?
They switch surface glycoprotein (VSG) causing antigenic variation. So immune system can’t recognise parasite.
what does Leishmania Braciliensis cause
mucocutaneous (American) leishmaniasis. skin lesions of oral and nasal mucous membrane.
where is Trichomonas tenax found?
size?
in the mouth, around teeth, cavities
6-10μm
