plamodium Flashcards
phylum and order of plasmodium
phylum: Apicomplexa
- unique feature: apical complex (to help invade host cells)
order: Haemosporida
- live within the blood, specifically blood cells
- intracellular parasites
apical complex purpose
- for host penetration
● Intermediate host: man
- whr parasite develops
● Final host: mosquito
-whr parasite completes its life cycle - for cell invasion
[esp RBC in bloodstreams]
what are the distinguishing features between these
1. Amoeba
2. Flagellates
3. Ciliates
4. Apicomplexa
- Amoeba – pseudopodia
- Flagellates – flagella
- Ciliates – cilia
- Apicomplexa – apical complex
plasmodium spp is aka
malarial parasite
it refers to multinucleated mass
plasmodium
- seen during diff lifecycle of malarial parasites
[because during its life cycle, it has multiple nuclei in some stages.]
- exhibit multinucleation (smthing to do w nucleus, w cell division)
[divides in a way that involves many nuclei forming before the cells split]
two life cycles (alternating) of the plasmodium spp
- asexual cycle
● “Schizogony”
● Occurs within the RBCs of vertebrate hosts (humans – intermediate hosts)
- consists of schizogony and gametony
[parasite multiplies and bursts the RBCs, causing malaria symptoms.]
- sexual cycle
● “Sporogony”
● Occurs within the mosquitoes (female anopheles) - (final hosts)
- consists of sporogony (8-35 days)
[parasite develops and spreads when mosquitoes bite humans.]
what are the plasmodium spp that can clinically infect the humans
[MVF.OK]
- Plasmodium malariae
● Discovered by Alphons Laveran in 1881 - Plasmodium vivax
● Discovered by Giovanni Battista Grassi and Raimondo Feletti in 1890 - Plasmodium falciparum
● First discovered by Laveran in 1881
● Renamed by William Welch in 1922 - Plasmodium ovale
● First described by Stephens in 1922 - Plasmodium knowlesi
● Named by John Sinton and Mulligan in 1932
what are the stages of development and its morphology
morphology: refer to index card
- trophozoite
- early trophozoite
- developing trophozoite - schizont
- immature schizont
- mature schizont - gametocyte
- microgametocytes (male sexual form)
- macrogametocytes (female sexual form)
morphology of trophozoite in general
○ Single nucleus
○ Ring-shaped or ring forms
○ With a red chromatin dot
○ Small amount of blue cytoplasm (Giemsa or Wright’s stain)
earliest stage after the invasion of RBCs
trophozoite
- aka trophic stage
stage after invading healthy RBC
early trophozoite
- ring stage or ring forms
how does the hemozoin form
plasmodium spp digests Hb from RBC for foos
since it cant use the iron part of Hb, it turns into hemozoin (a waste product)
it is an asexual stage where it occurs within the RBCs of the vertebrate hosts
schizont
- parasite usually divide when growing
- multiple rounds of nuclear division (mitotic division)
Occurs after the trophozoite stage and before mature schizont stage
immature schizont
this is where active chromatin replication is evident
immature schizont
- crowing chromatin w visible cytoplasmic materials
presence of fully-developed merozoites and absence of cytoplasmic material
mature schizont
- can produce a specific number of merozoites depending on the species
it is the sexual stage of the plasmodium life cycle and has a compact cytoplasm and one large compact and round or elongated nucleus.
gametocyte stage
- happens in the RBC
- prep for transmission to mosquitoes for reproduction
why is there an absence of nuclear division in the gametocyte
absence in human host in the stage of gametocytes as
- malarial parasites consumes too much energy
- since malarial parasites want to focus on survival and transmission rather than rapid division or raid proliferation
gametocyte may be differentiated as
Microgametocytes (male sexual form)
Macrogametocytes (female sexual form)
where can the Plasmodium falciparum be found
most frequently observed in peripheral blood (the blood flowing in your veins and arteries) due to its ability to circulate freely
= ez to detect under microscope
what is the shape of the gametocytes in Plasmodium falciparum
Banana/sickle/sausage/crescent
- common to both macrogametocyte and microgametocyte
*it is the key feature
what is the shape of the cytoplasm in Plasmodium falciparum mature trophozoite
comma-shaped
*heavy ring forms not commonly seen
what does macrogametocyte and microgametocyte have in common in the gametocyte stage of P. falciparum
○ Reddish pink nucleus
○ Few blue-black granules [hemozoin pigments] in the center of the cytoplasm or scattered.
Why are they there?
The parasite does not completely get rid of the digested hemoglobin, so hemozoin granules remain inside its cytoplasm.
Small red-staining structures found in RBCs infected by Plasmodium falciparum; seen only after staining.
Maurer’s dots
- aka Maurer’s clefts
- structures observed in an infected RBCs
- not in gametocytes rater seen inn RBCs
Which stages of Plasmodium falciparum are seen in a peripheral blood smear?
■ Ring forms
■ Gametocytes
*mature trophozoites and schizonts stages rarely seen in blood smears as they tend to hide in capillaries of internal organs like
- bone marrow
- liver
- brain
How long is the asexual cycle of
- Plasmodium falciparum
- Plasmodium vivax
- Plasmodium ovale
- Plasmodium malariae
- Plasmodium falciparum
48 hours (2 days) - Plasmodium vivax
48 hours (2 days) - Plasmodium ovale
48 hours (2 days) - Plasmodium malariae
72 hours - longest among human malarial parasites
Do Plasmodium falciparum infections enlarge RBCs?
No, infected RBCs remain normal in size.
When do gametocytes first appear in the blood during infection in P. falciparum?
After four weeks
- they usually do not appear in the blood for the first 4 weeks of infection
true or false:
RBCs become larger and paler when infected in Plasmodium vivax
true
- the mature ring form tends to be large and coarse
what stages of Plasmodium vivax can be seen in blood smear
all stages
(rings, trophozoites, schizonts, and gametocytes)
what are the small red-staining granules seen in infected RBCs in Plasmodium vivax
Schüffner’s dots
What type of pigment is seen in Plasmodium vivax-infected RBCs?
- Few coarse brown granules (digested hemoglobin)
- James’ dots (small red-staining granules)
- ay be prominent when stained
How does Plasmodium ovale affect RBC size and shape?
RBCs become enlarged with torn, jagged, or fringed edges.
What parasite stages of Plasmodium vivax can be seen in a blood smear?
All stages (rings, trophozoites, schizonts, and gametocytes).
which institutions offer post graduate training for identifying malarial parasites
RITM: Research Institute for Tropical Medicine
DOH: department of health
How do mature schizonts of P. vivax compare to those of P. malariae?
larger and more coarse in appearance
In which Plasmodium species are comet forms commonly seen?
Plasmodium ovale
- an oval-shaped RBC with a tail-like projection and ragged edges
- during the developing trophozoite stage
Why do comet forms occur in P. ovale infections?
P. ovale causes RBC enlargement and distortion = oval with jagged edges.
How can you distinguish P. ovale infections microscopically?
Look for
1. enlarged, oval RBCs with ragged edges (comet forms)
2. Jame’s dots.
What is the characteristic appearance of the young trophozoite chromatin in Plasmodium malariae?
One large red dot, giving a “bird’s eye appearance”.
Does Plasmodium malariae cause RBC enlargement?
No, RBCs remain normal-sized.
What special stippling pattern is seen in RBCs infected with Plasmodium malariae?
Ziemann’s dots (tiny red spots).
Which stages of Plasmodium malariae are seen in a peripheral blood smear?
All stages (ring, trophozoite, schizont, gametocyte).
the 2 hosts of plasmodium
vertebrate: man - intermediate host
mosquito: vector - final host
MOT of plasmodium
○ Mosquito bite or inoculation of mosquito
○ Blood transfusion
○ Congenital (placental transfer)
infective stage to the
man:
mosquito:
man: sporozoites (asexual)
mosquito: gametocyte (sexual)
diseases in
Plasmodium falciparum
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
FALCIPARUM
1. Malignant Tertian Malaria (most severe form – high mortality)
■ Tertian – fever pattern, usually every 3rd day
- Subtertian Malaria
- Estivoautumnal Malaria
■ Estivoautumnal – seasonal pattern, usually during summer
and early autumn
VIVAX
1. Benign Tertian Malaria
■ Benign – milder
OVALE
1. Benign Tertian malaria / Ovale Tertian Malaria
MALARIAE
Quartan malaria
■ Quartan – fever recourse every 4 days, Latin word that means fourth
How long does it take for malaria symptoms to appear after infection?
Takes 8 - 40 days (varies by spp.)
what is the clinical incubation for each plasmodium spp.
■ P. falciparum = 8 - 15 days
■ P. vivax = 12 - 20 days
■ P. ovale = 11 - 16 days
■ P. malariae = 18 - 40 days
What are some prodromal (early but nonspecific - flu-like) symptoms of malaria?
- Feeling of weakness and exhaustion
- Aching toes, limbs and back
- Desire to stretch and yawn
- Loss of appetite
- Headache
- Nausea
- Vomiting
The hallmark symptoms of malaria, occurring at the end of the schizogonic cycle when merozoites are released from infected RBCs.
malarial paroxysms
- occur at the end of the schizogonic cycle
- release of merozoites from infected RBC.
briefly explain the stages are there in a malarial paroxysm
- Cold Stage (Chill) - 15 minutes to 1 hour
- peripheral BV are constricted
- clinical manifestation:
○ Sudden feeling of cold
○ Mild shivering that quickly turns into violent teeth chattering
○ Shaking of the whole body - Hot Stage (Fever) - for 2 to 6 hours
- clinical manifestation:
○ Body temperature increases up to (39 to 41°C).
○ Nausea
○ Vomiting
○ Headache
○ Rapid pulse
○ Hot skin
○ Flushed face
○ Confused or delirious - Wet Stage (Sweating) - 8-12 hours of typical attack (paroxysm).
- patient perspires profusely
- body temp drops
*Interval between attacks is determined by the length of the erythrocytic cycle. [how fast the parasite multiplies in RBCs]
*body temperature drops back to normal, signaling the end of the attack.
what does each plasmodium infect
Plasmodium falciparum
Infects: All RBCs (young & old) → High parasite levels
*infect RBC of all ages
- fatal type of malaria due to vascular obstruction.
- enters kidney, brain and liver
**Kidney:
○ Black water fever = marked hemoglobinuria (presence of
hemoglobin in urine)
○ Acute renal failure, tubular necrosis, nephrotic syndrome, cerebral malaria (brain), death
Plasmodium vivax & Plasmodium ovale
Infects: Only young or immature RBCs
- less severe than P. falciparum
Plasmodium malariae
Infects: Only mature or older RBCs
- can cause:
Anemia
Multiple organ pathology (tissue anoxia)
endemic areas in the Philippines
Provinces with slow, flowing,
partly shaded, clean mountain
streams.
breeding habitat of
major vector vs minor vector
major vector:
○ Anopheles minismus flavirostris
minor vector:
○ Anopheles mangyanus = clean stream breeder
○ Anopheles balabacensis = forest rain pool breeder
○ Anopheles litoralis = brackish water breeder
○ Anopheles maculatus = stream breeder
Malaria & Mosquito Transmission
Cause: Malaria is spread by the female Anopheles mosquito
How? Mosquito bites an infected person → Picks up parasites → Bites a new person → Spreads malaria
Malaria cases in 2023: Increased by 90% (DOH report)
Malaria-Endemic Areas in the Philippines (2022)
Most active cases:
Palawan
Other endemic provinces:
Sultan Kudarat
Davao del Norte
Maguindanao
Sulu
Occidental Mindoro
Tawi-Tawi
Cagayan Valley
Davao City
treatment
- Chloroquine = DRUG OF CHOICE
- Artemether & lumefantrine: P.
falciparum (when patient is resistant to
chloroquine) - Pyrimethamine/sulfadoxine combination
- Quinine
- Doxycycline: prophylaxis
- Fluid replacement
- Blood transfusion
drug of choice
Chloroquine
this drug is taken when patient is resistant to chloroquine
Artemether & lumefantrine
prevention and control methods
- Screening of houses
- Use of mosquito nets
- Protective clothing
- Insect repellants
- Apply every 4 hours - Early diagnosis and prompt treatment
- Chemical insecticides and larvicides (vector control)
what are the interval time from sporozoite inoculation to detection of parasites in the blood is dependent on the prepatent period
★ P. falciparum = 11 - 14 days
★ P. malariae = 3 - 4 weeks
★ P. ovale = 14 - 26 days
★ P. malariae = 11 - 15 days
time interval between initial infection with the malarial parasite and appearance of parasites in the blood, between infection and onset of symptoms
prepatent period
what are the lab diagnosis that can be used in plasmodium
- Microscopy (gold standard)
Blood Smear: Thick & Thin
Specimen: Capillary blood (preferred)
Stain: Giemsa - Malarial parasite count
- Quantitative buffy coat (QBC) method
- Rapid diagnostic tests (Immunochromatography)
● ParaSight F Test:
- Dipstick test
- Quickly detects P. falciparum infection - Serologic tests
● ELISA
● IHA
● IFAT - Molecular
● PCR - Culture
● Culture media: RPMI 1640
Thick smear →
Thin smear →
Thick smear → Detects presence of parasites
Thin smear → Identifies species & stage
WHO Recommendation for Negative Thick Smear in Malarial parasite count
For a thick smear to be considered negative, at least 100 fields (each containing ~20 WBCs) must be examined without finding parasites.
Thick and Thin Smear Parasite Count Formula
THICK
Parasites are counted against WBCs.
Stop counting after 200 WBCs.
Formula:
(No. of parasites counted / 200 WBCs) × 8000
THI
Parasites are counted against RBCs.
Formula:
(Parasitized RBCs / Total RBCs) × 100
QBC (Quantitative Buffy Coat) Method
Uses a specially prepared capillary tube coated with Acridine Orange
Viewed under a fluorescent microscope
Positive for Malarial Parasite → Bright green & yellow fluorescence
life cycle
transes
each infected bite contains how many sporozoites
20 to 200
*came from the salivary glands of female anopheles mosquito
dormant schizonts, inactivated that can relapse once activated
hypnozoites
what are the 3 stages in asexual or schizogony
pre-erythrocytic stage (liver stage):
Sporozoites (from mosquito bite) → travel through the blood → invade liver cells
Inside liver cells, sporozoites multiply to form schizonts
Schizonts rupture → release merozoites into the bloodstream
P. falciparum: 5–7 days
P. vivax: 6–8 days
P. ovale: 5 days
P. malariae: 13–16 days
exo-erythrocytic stage (outside the blood):
Some parasites stay in the liver instead of entering the blood
Merozoites can infect other liver cells
Some parasites become dormant hypnozoites (inactive form)
Hypnozoites can reactivate later → relapse/reinfection
erythrocytic stage (inside rbc):
This stage causes the symptoms of malaria
➡ Merozoites invade RBCs
➡ Develop through different stages:
Ring form → Trophozoite → Immature Schizont → Mature Schizont
Schizonts rupture → release more merozoites → infect new RBCs (cycle repeats)
Some parasites become gametocytes (the stage that can infect mosquitoes)
If an uninfected mosquito bites an infected person, it picks up gametocytes, completing
sexual or sporogony cycle
mosquito bite infected person
gametocyte enters it’s body
- micro: undergo exflagellation
-macro: ready for fertilization
*micro fertilize macro = zygote
form ookinete (motile form)
penetrates it’s midgut wall to form oocyst
-grows, divide and produce sporozoites (20to200)
travel to it’s salivary glands for it to be infective
infect another human
Marked hemoglobinuria
Black water fever
