Malaria pt2 Flashcards
malarial parasites Infecting the RBCs would cause
malarial
paroxysm
malarial stage/cycle:
sporogony occurring in definitive host
SExual stage
malarial stage/cycle:
(schizogony occurring in the
intermediate host)
Asexual stage
This is the mosquito that commonly carries
malarial parasites.
Anopheles Minimus Flavirostris mosquito.
Harbors the Asexual reproduction of the parasite for it to continue
its cycle going back to the moquito.
MAN (IH)
This happens when red blood
cells are exploding because they are being
infected by the parasite a.k.a. The
Plasmodium spp.
Malarial paroxysm
Chronic malaria leads to
anemia
which is associated with
impaired physical and mental growth and development in
children. In pregnancy, anemia is a leading contributor to
maternal morbidity and mortality, and is associated with
risk of cardiac failure and adverse perinatal outcomes.
Also known as the asexual reproduction
which happens in man.
Schizogony
sporozoite to gametocyte
This is the process wherein schizonts are produced.
Schizogony (asexual reproduction in man)
can infect hepatocytes and RBCs
due to the contents which are your
merozoites.
Schizonts
This is the sexual reproduction of the
parasite which happens inside the female Anopheles
mosquito.
Sporogony
leads to the formation of
sporozoites.
leads to the formation of
sporozoites.
Once the female anopheles has injected the sporozoites, These sporozoites will infect firstly, the
liver (hepatocytes/parenchymal cells?)
What organ does schizogony takes place
liver
also known as pre-erythrocytic
schizogony or exo-erythrocytic schizogony
Immature schizonts are called
schizones?
Stage of the formation of merozoites
schizones
contents that are formed inside the liver cells and they
are capable of infecting red blood cells and other liver
cells.
merozoites
The moment that the schizont explodes, it will release the ___ and it can infect the RBCs and liver cells.
Merozoites
Release of merozoites after the bursting of
hepatocytes will infect other liver cells and just repeat
its cycle.
These dormant stages of parasites inside the
liver cells are deadly and they are called
hypnozoites
Hypnozoites are formed from
merozoites that stayed inside the hepatocytes and
these are called the “dormant stages” of malaria.
Formation of hypnozoites are very common in infections of
P. vivax and P. ovale
Clinical features (signs and symptoms) of malarial infection is seen when
the malarial parasite is already inside the peripheral blood (RBCs)
Merozoites will enter RBCs and it will undergo
asexual reproduction
the type of asexual
reproduction inside the RBC is called as the
“erythrocytic shizogony.”
When merozoites infect RBCs, it will form
ring form
immature trophozoite
with chromatin dot and cytoplasm.
stage of parasite with ring inside, chromatin dot and cytoplasm
ring form / immature trophozoites
The most distinct ring forms are seen in what species
P. falciparum and P. vivax
the mature trophozoites in RBCs will developp into
schizonts with merozoites
In the RBCs some merozoites will develop as either
micro and macrogametocyte (gametogony) or erythrocytic shizogony
In order for the female anopheles to be infected it has to suck what stage parasite
both the micro and macrogametocyte
Inside the mosquito, they will reunite and it will form a zygote or ookinete
(motile form of zygote) and is capable of going to the
gut
Microgametocyte and macrogametocyte
Inside the mosquito, the zygote has a flagellate and can go to the gut and form
oocytes –> oocyst / sporoplast
contains many sporozoites
Stages of parasite in mosquito
Zygote - This forms after the union of gametocytes.
Ookinete - developed zygote; spindle shaped; found in gut of mosquito
Oocyst - develop and contain spotozoite
Sporozoite - found in the salivary glands
The entire developmental cycle in the mosquito take
8 to 35 days, depending to some extent
on ambient temperature
Stages of parasite in man
sporozoites are injected in man
Schizont - dividing forms of parasite
Trophozoite - growing form
Gametocyte - sexual forms
Usually applique or Accolle in P. falciparum
Ring form (trophozoite) found protruding on the surface
Applique means at the
periphery of the RBC.
P. falciparum infect what type of RBCs
Young (reticulocytes)
Old
Asexual schizogony takes place ___ hours upon infection
36-48 hours
Distinguishable features of macrogametocyte and microgametocyte in P. falciparum
Macrogametocyte: crescent-shaped medyo mataba; Compact Chromatin
Microgametocyte: banana-shaped, or
sausage-shaped in appearance; Diffuse Chromatin
Double ring form / Double chromatid dot – common in what specie
P. falciparum
Double ring form / double chromatid dot is caused by
1:1 or 1:2 (one red cell infected by two parasites resulting to the double ring form)
P. falciparum is considered the most dangerous malarial parasite because
it has the highest number of merozoites in a single red cell
Causative agent of Malignant Tertian
malaria or Black Water Fever
P. falciparum
What is the malaria caused by P. falciparum
Malignant Tertian
malaria or Black Water Fever
P. falciparum has presence of RBC stages:
ring forms
Gametocyte
Very seldom trophozoite is seen in this specie
P. falciparum
Dot / stippling seen in P. falciparum
Maurer’s dot
Also called tropical malaria
p. falciparum
Has a febrile / erythrocytic cycle / paroxysmal cycle of 48 hours
P. vivax
P. vivax causes what malaria
Benign tertian malaria
P. vivax affects what stage of RBCs
Young / reticulocytes /
polychromatic erythrocytes
Size of Parasitized
RBC of P. vivax
Enlarged RBC (1.5 – 2 times)
Size of Parasitized
RBC of P. falciparum
Normal
what stages of P. vivax are present inside RBCs
All stages present
Trophozoite of P. vivax is characterized as
Ameboid (bizarre looking; IRREGULAR shaped)
Trophozoite of P. falciparum is characterized as
Heavy ring forms; not commonly seen
How many merozoites in P. vivax
12-24
microgametocyte and macrogametocyte of P. vivax
Microgametocyte: Round; large pink to purple chromatin mass surrounded by a pale halo
Macrogametocyte: Round; eccentric chromatin mass
Dots / Stippling of P. vivax
Schuffner’s (eosinophilic) more common
dot or stippling that is characterized by
Pink, fine granules in the infected red blood cells.
○ Medyo mamula mula or eosinophilic in nature.
Schuffner’s dots in P. vivax
What specie has a ring form with 1/3 diameter of RBC
• Heavy Chromatin Dot
• Signet Ring
Appearance
P. vivax ring form`
TRUE OR FALSE
Usually in a malarial parasite, except in P. falciparum, the
ring form is found inside/middle of the RBC
TRUE
TRUE OR FALSE
P. falciparum schizont is easily detected in blood smear
FALSE
P. falciparum schizont is usually not detected in blood
smear unless it’s already in the severe form of the
malaria
The second most common malarial parasite found in the
Philippines is the
P. vivax
Infected RBCs are Enlarged are caused by
P. vivax and P. ovale
Infected RBCs are in normal shaped are caused by
P. falciparum and P. malariae
o Usually seen in almost all erythrocytes that contains the
mature stages of the malarial parasite
o These are said to be the degradation products of
hemoglobin
Hemozoin pigment
TRUE OR FALSE:
All malarial species have a gametocyte that are rounded in shape
FALSE
vivax, malariae, and ovale are usually
rounded but for falciparum, it is sausage-shaped or banana
shaped and not knowlesi
P. ovale cuases what malaria
ovale tertian malaria
Infected RBCs of P. ovale causes
Enlarged, Oval, Fimbriated, Serrated
Predominant stage or stages present in RBC of P. vivax
all stages are present (but mostly trophozoite?)
Ring form of P. ovale is
larger rings
similar to P. vivax
Trophozoite of P. ovale is characterized as
Ring shaped; non ameboid;
Number of merozoites in P. ovale
8 merozoites
Gametocytes of P. ovale are
Both round like P. vivax but smaller compared to P. vivax
Hemozoin pigments of the P. ovale
James dots
○ Shows pores/porous
○ coarser/darker in color
○ Red orange color
Febrile/
Erythrocytic Cycle/ Paroxysmal cycle of P. malariae
72 hours
P. malariae causes what malaria
Quartan Malaria
P. malariae infects what stage of RBCs
Old / Senescent
Predominant stage present in RBCs infected by P. malariae
Few Rings, mostly
trophozoites and
schizonts
Ring forms of P. malariae is characterized as
• Smaller rings (1/8 of cell) • Heavy Chromatin Dot (Bird’s Eye Appearance)
Trophozoite of P. malariae is characterized as
Band Shaped
Trophozoite; Basket
Forms may be seen
Number of MErozoites of P. malariae schizonts
6 – 12 Merozoites;
Rosette or Fruit pie
appearance
Hemozoin pigment of P. malariae
Ziemann’s
Micro and Macrogametoyte of P. malariae are characterized as
Round and smaller than P. vivax
Ring form forms bird’s eye appearance
P. malariae
Malaria caused by P. knowlesi
Quotidian Malaria
Non-relapsing Plasmodium specie
P. knowlesi (and P. falciparum??)
PReferred specimen for diagnosing malaria
Peripheral/Capillary Blood collected at the height of
the fever or every 6-8 hours
In diagnosing P. malaria we can only detect ____ and ___ 10 days after symptoms begin
Ring forms
Gametocyte 10 days after symptoms begin
Obtaining smears every _ to _ hours is usually appropriate
6 to 8 hours
smear for parasite screening and sensitivity
Thick smear
smear for Identification and specificity
Thin smear
Smear for parasite screening
Thick smear
Smear for parasite identification.
Thin smear
Size of blood drop for thick smear
dime or 25 centavo coin
Angle of the pusher / spreader slide in making the smear
45 degrees angle
Thick film smears must be completely __ before staining
air dry before staining
Puncture the finger about __ deep
2mm
To control the size of the blood drop on the slide,
touch the finger
to the slide from below.
For the think smear, using the corner of another slide, spread the blood drop into the shape of a
circle or square with a size of ~1cm^2 or size of a dime or 25 centavo coin
Scanning for the presence of Malarial Parasites should be
done under what microscope objective
Oil immersion objective
smear for For malarial count
Thick smear
Dehemoglobinizing agent for thick smear
distilled water
Dehemoglobinize with water before staining with Giemsa
What smear can be stained immediately no need to fix with MEOH (Methanol)
Thick smear
Giemsa pH
7.2-7.4
adjusted by adding phosphate buffered
saline to the Giemsa Staining Solution
Formula of no. of malarial parasite in uL
of malarial parasite / 200 * 8000
Smear Used mainly for identification of species using its morphology.
Thin smear
Smear that has to be fixed with MEOH (methanol) or Methyl alcohol before staining with Giemsa
Thin smear
Diagnostic Tests for malarial parasite
Thick and Thin Smear Quantitative Buffy coat Rapid Diagnostic Test Serologic Test Molecular Methods
Diagnostic test that makes use of Immunochromatography in nature
RDTs Rapid Diagnostic Test
Diagnostic test that detects Plasmodium-specific antigen (Ags)
RDTs Rapid Diagnostic Test
What are the Plasmodium-specific antigen (Ags)
Hrp-2 Histidine-rich protein 2 - P. falciparum
PLDH Plasmodium lactate dehydrogenase - sexual and asexual stage; P. falciparum and non-P. falciparum
Plasmodium aldolase
- produced by all plasmodium species
Diagnostic test that makes use of fluorescence microscope
QBC Quantitative buffy coat
Makes use of WBCs
Diagnostic test that makes use of Acridine orange stain
QBC Quantitative buffy coat
Buffy coat will be stained with acridine orange for it to be viewed under fluorescence microscope
Capillary tube lalagyan ng capillary blood & incubate
it with acridine orange stain and you will see…
Color of the parasite under fluorescence microscope
Bright green and Yellow (Apple green and yellow green)
water soluble
proteins which are produced by both trophozoites and
young gametocytes. This is very helpful to detect
(screening only but will not confirm presence /
absence of..) P. falciparum.
HRP-2 (histidine rich protein-2)
This plasmodium specific antigen is highly sensitive for diagnosis of severe malaria from all species.
pLDH
TRUE OR FALSE
pLDH and aldolase based RDT demonstrated sufficiently
high overall sensitivity for P. knowlesi.
FALSE
neither the
pLDH nor aldolase based RDT demonstrated sufficiently
high overall sensitivity for P. knowlesi.
Advantages of the RDTs
• You can have the result as fast as 15-30 minutes,
depending on the manufacturer.
• Can be used even without electricity kasi ang kailangan
mo lang ay yung kit
• Special equipment are not needed
• No need for training in microscopy
Disadvantages of the RDTs
• Lack of sensitivity at low levels of parasitemia which may
result to false negative result
•can detect the absence or presence of a malarial
parasite, but it cannot quantify the parasite density.
Inability to quantify the parasite density.
• It cannot differentiate Plasmodium ovale, Plasmodium
malariae, and Plasmodium vivax.
• Persistent positive despite parasite clearance.
• More expensive compared to the thick and thin blood
smear
2 types of serologic test
IFAT Indirect Fluorescent Antibody Test
IHA Indirect Hemagglutination
ELISA Enzyme linked immunosorbent assay ????
Principle of QBC
The principle of this procedure is that the acridine orange
will bind to the nucleic acids of the malarial parasite
(nucleus)
o RBCs will not stain because it lacks a nucleus (mature
red cells do not have a nucleus)
A serologic test involved in the detection of Plasmodium bodies
IFAT Indirect Fluorescent Antibody Test
Indirect testing :
Direct testing:
Indirect testing : antibodies
Direct testing: Antigen
This molecular method significantly
enhances microscopic diagnosis of malaria especially in low
cases of parasitemia and mixed infection.
Polymerase Chain Reaction (PCR)
Band formation, rosette arrangement of merozoites and
normal sized infected RBCs are all associated with which
species of Plasmodium? Give the complete scientific name
Plasmodium malariae that causes Quartan Malaria
True or False: IFAT detects antibodies against Plasmodium
True
○ IFAT is used to identify antibodies caused by
Plasmodium infection
Which species of Plasmodium is endemic in South East
Asia and can be mistaken for P. malariae? Give the
complete scientific name
Plasmodium knowlesi
○ It was zoonotic before but cases nowadays have
seen cross-infection between monkeys and apes to humans. Little by little, it is transforming to a
Plasmodium capable of infecting humans.
○ This plasmodium is sometimes mistaken as
Plasmodium malariae
Sausage shaped gametocytes, accole and applique ring
forms are all associated with which species of
Plasmodium? Give the complete scientific name
Plasmodium falciparum
○ Accolé and applique ring forms are seen in RBCs.
There are a lot of these in the peripheral blood
that would show multiple infections caused by P.
falciparum.
○ Sausage-shaped gametocytes: these are the
microgametocytes (male)
➢ Chromatin dots are clumped in male
gametocytes
○ Macro gametocytes (female): mataba ng onti.
Chromatin dots are diffused
True or False: Fixation of the thick smear is required
False
○ Fixation is only required in thin smear using
methanol. Thick smear would only require
dehemoglobinization and then staining.
Infective stage to the FH in the life cycle of Plasmodium
Gametocyte
Which Plasmodium produces a rosette pie appearing
schizont? (Give the complete scientific name)
Plasmodium malariae Schizonts
Which species has the longest paroxysmal cycle? (Give the
complete scientific name)
P. malariae (72 hours) (research only)
The most virulent species of Plasmodium causing malaria?
Give the complete scientific name
Plasmodium falciparum
The sequence of chills, fever and sweating occur every
_____ hours in cases of quartan malaria.
2-4 hours
○ The malaria paroxysm comprises three
successive stages. The first is a 15-to-60 minute
cold stage characterized by shivering and a
feeling of cold. Next comes the 2-to-6 hour hot
stage, in which there is fever, sometimes
reaching 41°C, flushed, dry skin, and often
headache, nausea, and vomiting. Finally, there is
the 2-to-4 hour sweating stage during which the
fever drops rapidly and the patient sweats.
Enumerate 2 malarial antigens detected by Rapid
Diagnostic Test.
Histidine rich protein 2, Plasmodium Lactate
[Dehydrogenase and Aldolase]
