Protozoa - Sarcomastigophora - Flagellates & Sarcodina Flashcards
Protozoa
simple sg cell organism
2-100um
Protoplasm enclosed by cell membrane differentiated into cytoplasm (outer hyaline ectoplasm - protection, locomotion, ingestion, excretion; inner granular endoplasm) + nucleoplasm
Can transform from active state (trophozoite) >inactive cyst stage (tough wall, protoplasmic body=cyst - can’t grow/multiply, resistant stage therefore infective to humans)
Repro
Assexual - binary fission, multiple fission (schizogony - >2 indivs produced)
Sexual - conjugation (temp union where interchange nucleur material ->seperate), syngamy (games unit permanently fuse > zygote)
Nucleus - contain dispersed chromatin and central karyosome
ER
Food storage granules
Contractile and digestive vacuoles
Motility organelles: simple cytoplasmic extrusions/pseudopods, flagella, cilia
Classification
1 - Rhizopoda (amoeba) - pseudopodia
2 - Mastigophora (flagellates) - flagella
3 - Sporozoa - no organ of locomotion, exhib slight amoeboid movement
4 - ciliates - cilial
Phylum sarcomastigophors subphylum mastigophora class kinetoplastidea, order trypanosomatida family trypanosomatidae Genus - Leishmania + Tryanosoma
Heteroxenous (definitve host w/ insect intermediate vectors) blood flagellate (i.e. matsigophora)
Round/oval nucleus, kinetoplast (deep staining parabasal body + adj blepharoplast connected y 1/1+ thin fibrils)
Flagellum - originate from blepharoplast (axoneme = from blepharolast to surface of bodt)
Diff cell types during life cycle stage
Amastigote - round/ovoid w/o ext flagellum, nucelus, kinetoplast, axial filaments. Axoneme extend to ant end of cell
Promastigote - lanceolate shape, antinucleur kinetoplast > flagellum emerges here, no undulating membrane (infective stage of Leishmania)
Epimastigote - elongated w/ kinetoplast more post (juxtanucleur kinetoplast). flagellum run along body as short undulating membrane and emerge anteriorly [trypsanoma brucei for in salivary gland of vector + trysonoma cruzi in midgut of reuviid bug - NOT in Leishmania}
Trypomastigote - elongated spindle shaped, central nucleus, postnucleur kinetoplast, flagellum runs along entire cell (long undulating membrane > emerge as free flagellum anteriorly) [infective stage of trypanosomas found in arthopod vector, NOT found in Leishmania]
Trypanosoma bruzei gambienese & rhodesiense- Morphology + Distribution
Gambienese
Distribution - tropical West +central Africa
Habitat - Live in man + other vertebrae CT, invade lymph nodes and blood and may move to CNS
Vector - tsetse fly (glossina palpalis)
Rhodesiense
Distribution - Eastern & central Africa
Vector - woodland tsetse fly (glossina morsitans group_
Morphology (both similar)
Vertebrate blood of host - polymorphic - trypomastigote form (15-40um x 1.5-3.5um), long slender form, stumpy short broad form (attenuated/absent flagellum) and intermediate form, metacyclic trpomastigote=infective to humans
Insect - Epimastigots and metacyclic trypomastigote form
Trypanosoma bruzei gambienese & rhodesiense - Life cycle
Gambienese
Human = definite host; Tsetse fly = intermediate host (glossina palparis)
Reservoir = humans by pigs & other domestic animals can act as chronic assymptomatic carriers
Rhodesiense
Human definite
Vector - woodland tsetse fly (glossina morsitans group
Reservoir - wild game
Lifecycle (Same)
Takes around 3 W
1 - Tsetse fly takes blood meal and inject metacyclic trypomastigotes
2 - Injected metacyclic trypomastigotes transform > blood stream trypomastigotes (long + slender) which multiply assexually 1-2 days before entering periph blood + lymph
2 - >intermediate > stumpy > enter periph blood & lymph (cn invade CNS in chronic infection)
3 - Stumpy trypomastigote ingested by tsetse fly during blood meal > procyclic bloodstream trypomastigotes +; binary fission
4 - in midgut of fly > when leave they > long + slender + multiply > epimastigotes
5 - After 2-3 W > migrate into salivary glands multiply + fill cavity of gland > metacyclic trypomastigotes
Trypanosoma bruzei gambienese + Rhoesiense - Disease
Gambienese
African trypanosomiasis (west AFrican sleeping sickness)
Chronic - persist for yrs, intermittent fevers, headaches, muscle + joint pain, swollen lymph nodes, CNS -> personality change, daytime sleepiness w/ night time disturbance, progressive confusion, chronic infection
Diagnosis - blood film, lymph node fluid
Treatment - Suramin w/ pentamidine alternative
Rhodesiense
African trypanosomiasis (East African sleeping sickness)
Acute (4 W incubation period) + more fatal (terminate w/i yr)
Oedema, myocarditis, weakness, fever, headaches etc. W/i few weeks parasite invade CNS -> mental deteriation and other neuro problems
Diagnosis - Blood smear
Trypanosoma cruzi - Morphology
Amastigote - round/ovoid, no flagellum, nucelus, kinetoplast, axial filaments. Axoneme extend to ant end of cell
Multiplication stage is here
[found in tissues in sm groups of cyst like collections]
Epimastigote - elongated w/ kinetoplast more post (juxtanucleur kinetoplast). flagellum run along body as short undulating membrane and emerge anteriorly
BInnary fission in hindgut of vector
[found in insect vector}
Trypomastigote - elongated C/U/S shape 20um/ stumpy 15um, central nucleus,
posterior=wedge shaped postnucleur kinetoplast, flagellum runs along entire cell (long undulating membrane > emerge as free flagellum anteriorly)
Not multiply in human & taken up by insect vectors
Metacyclic = infective forms
[in blood ]
Trypanosoma cruzi - Lifecycle
Definite host - man
Intermediate vector - Reduviid bug/ triatomine bug
Reservoir - Armadillo, cat, dog, pigs
1 - bug take blood meal (passes metacyclic trypomastigotes in feces) > feces rubbed into wound/via mucosal membrane
2 - Trypomastigotes penetrate various cells at wound site > inside > amastigotes
3 - Binary fission of amastigotes in infected tissue cells
4 - intracellular amastigotes > trypomastigotes > burst out into blood stream (can reinfect other cells)
5 - Bug take blood meal and ingest trypomastigotes
5 - >epimastigotes in midgut + multiply
6 - >in hindgut > metacyclic trypomastigote > excreted in feces
Trypsonoma cruzi - Disease
Chaga’s Disease
Pathogenesis
Acute phase - Amastigotes can kill cells and cause inflammation (cardiac muscle frequently affected) > arrythmias , megacolon (loss of tone), megaoesophagus
Chronic phase - persist in amastigote form
Symptoms
Assymptomatic acute
Chronic
Initial chagoma (erythematous + indurated area)/romanas sign in conjuctiva > rash + oedema, fever, chills, malaise, myalgia
Chronic - hepatosplenomegaly, myocarditis, megocolon + megaoesophagus (nerve cell destruction)
Diagnosis - blood film
Treatment - nifurtimox
Leishmania - Morphology
Tissue flagellates
Obligate intracellular parasites w 2 hosts (mammalian - amastigotes + insect vector - promastigotes; female sandfly)
Morphology
Amastigote - typically sm 2-5umx1-3um, oval, intracellular, found in phagocytic vacuoles of macrophages and other mononucleur phagocytes. Most DNA packed into kinetoplast
Promastigote - found in sandflies, 14-20um, long delicate ant flagellum, central nucleus, kinetoplast
Repro via binary fission
Leishmania donovani - Life cycle
Visceral leishmania - visceral tissue
Female sandflies in inter-tropical and temperate regions are the vector for the parasite.
Host - humans + dog
Habitat - reticuloendothelial system of viscera, mainly liver, spleen, BM, sometimes skin, intestinal mucosa +mesenteric lymph noses
1 - Blood meal > sandfly releases promastigotes through the proboscis into the skin.
2- Macrophages phagocytise the promastigotes. Promastigotes > amastigotes
3 - Amastigotes proliferate in cells > signs and symptoms of the disease become particularly prevalent. Macrophages rupture + release amastigotes
4 - Amastigotes in periph blood (also also phagocytosed by other macrophages)
4 - Sandfly takes a blood meal and ingests macrophages containing amastigotes.
5 - form flagella + multiply in gut
6 - > metacyclic promastigotes (infective stage) in the sandfly’s midgut
6 - migrate > pharynx > proboscis, ready to be released during the next blood meal.
Leishmania donovani - Disease
Visceral leishmaniais (Dum dum fever, Kala-azar -) - most case world wide inc India, Nepal, Bangladesh, Sudan
Pathogenesis
Organs of reticuloendothelial system affected, reduced BM activity
Symptoms
intermittent fever, weight loss, Enlarged spleen and liver, low blood cell count (can be life threatening).
Post Kala-azar leishmaniasis - 3-10% butterfly distrubition of erythrematous patches, nodular lesions
Diagnosis -
Tissue biopsy
Amastigotes intracellularly + extracellularly
blood, BM tissue culture
Leishmania tropica
Cutaneous parasite
FOund in middle east, India, Afghan, east mediterranean, north africa
Amastigote form - reticuloendothelial cell of skin
Promastigote - sandfly vector
Morphology same as donovani
Life cycle - similar to donovani except
ingested by sandflies feeding near skin lesion, and confined to skin (no transport to int organs)
Disease = cutaneous leishmaniasis
symptoms - oriental skin sores starting a papules/nodules, may > ulcers. Sores can be painless/painful. satellite lesions
Diagnosis - smear - find amastigotes
Skin test
Leishmania donovanii infantum
Visceral + cutaneous leishmania
Distribution - mediterranean coast, mid east, China
Reservoir = dog, fox, jackal, wolf
Transmission - zoonotic
Leishmania mexicana
Leishmania Braziliensis
Mucocutaneous leishmaniasis
Habitat - intracellular, amastigote in skin, mucosa of nose and buccal cavity, promastigote in sandfly
Distribution - braziliensis = tropical south americaa, mexicana - central america and amazon basin
Resevoir - forest rodent
Transmission - zoonotic
Lifecycle -
similar to L donovani except mastigotes found in reticuloendothelial cells, lymphoid tissue of skin but not int organs, direct transmission & autoinfection occu man-to-man
Mexicana - cutaneous - chiclero ulcer (ulceration in pinna)
Braziliensis - most severe & destructive involving nose, mouth + larynx, espundia (enlargement of nose + lips)
Trichomonas
Morphology
Species - T vaginalis (urogenital flagellate, largest, only pathogen), T hominis (intestine), T. Tenax (mouth)
T vag
- NO cyst form (not survive well in external environment)
- Trophozoite(active feeding stage) - pear shaped, 10-30x5-10um size, 4 ant flagella + 5th running along outer margin of undulating memb (supported by costa), prominent axostyle throughout length projecting post, siderophillic graniles in cytoplasm, motile w/ jerking/twitvching type movement
T. hominis
-8-12um, pyriform shape, 5 ant flagella, harmless commensal, transmission via fecal-oral
T. tenax
- harmless commensal
- 5-10um (smaller)
- transmit by kissing via salivart droplet
