(M) Plasmodium (lecture-based) Flashcards
Dr. Jasper Pablo coverage
Phylum
Sporozoa (formerly known as Apicomplexa)
Class
Sporozea
Subclass
Coccidia
Superorder
Eucoccidea
Order, Suborder and Family of Plasmodium
Haemosporida, Aconoidna, Haemospiridae
The malaria antigen was detected in? dates back from 3200-1304 BC
Egyptian remains
Indian writings of the Vedic period (1500 - 800 BC) called malaria the?
King of diseases
In 270 BC, who linked tertian and quartan fevers with splenomegaly and blamed malaria’s headaches, chills, and fevers on demons in Chinese literature
Nei Chin
According to Nei Chin, what are the 3 demons?
one carrying a hammer (headaches), another carrying a pail of water (chills), and the third a stove (fever),
He mentions Malaria in The Iliad, as foes Aristophanes in The Wasps, and Aristotle, Plato, and Sophocles
Homer
He described the disease in a medical text in the 4th or 5th century BC
Hippocrates
This person may have died of a Malaria infection at age 30
Alexander the great
TOF. The greek physician, Torti, coined the term Malaria in 1718.
F (italian)
Italian word Malaria which means?
Bad air
Roman physicians believed that the disease was caused by?
malignancies in the swamp air
- Definitively showed that Malaria is caused by another type of single-celled organism, a protozoan of the Plasmodium family, which attacks RBC’s
- 1907 Nobel Prize Winner in Physiology or Medicine
CHARLES LOUIS ALPHONSE LAVERAN
What did Laveran discovered?
protozoan plasmodium
He found out that the plasmodium is the causative agent of Malaria
CHARLES LOUIS ALPHONSE LAVERAN
Over how many species of plasmodium have been described?
200
Plasmodium species are limited to five
Plasmodium falciparum
P. ovale
P. vivax
P. malariae
P. knowlesi
still considered a zoonotic plasmodium, i.e. it is a disease of animals such as Macaque monkeys
Plasmodium knowlesi
In the 2022 CDC update, Malaria has remained to be endemic in the ff regions:
- Central and South America
- Africa
- Middle East
- Asia
CA SA A A M E
TOF. In 2023, the Department of Health (DOH) reported a decrease in the cases of Malaria
F (increase)
only province in the Philippines where Malaria is endemic
Palawan
there are more regions where Malaria has become endemic, other than palawan
Occidental mindoro and Sultan kudarat
Species
- most widespread
- can be life threatening
P. vivax
primary Malaria species of public health importance in the Philippines are?
P. falciparum and P. vivax
This species comprise 88% and 9% of the total indigenous Malaria cases
P. falciparum and P. vivax
The vectors (6)
- Anopheles minimus
- A. flavirostris
- A. litoralis
- A. maculatus
- A. mangyanus
- A. balabacensis
P. vivax
A. Malignant Tertian Malaria
B. Benign Tertian Malaria
C. Ovale Tertian Malaria
D. Quartan Malaria
E. Quotidian Malaria
B. Benign Tertian Malaria
P. vivax
TOF. Widespread location is in Sub-Saharan Africa, Southeast Asia, South America.
F (Southeast Asia and Latin America; for P. ovale ‘yan)
isipin mo nalang na may viva max sa asia at latin america
For one to be infected with P. vivax, one must possess?
Duffy antigens
p. vivax
produces what color?
Yellow-brown colored pigment
Schuffner dots
- Last of the malaria parasites of humans to be described
- Rarely causes severe illness or death
- Relatively unusual to acquire infections outside Africa
P. ovale
P. ovale
AKA
A. Malignant Tertian Malaria
B. Benign Tertian Malaria
C. Ovale Tertian Malaria
D. Quartan Malaria
E. Quotidian Malaria
C
PLASMODIUM OVALE
Endemic
West africa & South africa
PLASMODIUM OVALE
TOF. There have been rare cases of P. ovale infection in the Philippines, other Asian countries, and in Papua New Guinea.
T
PLASMODIUM OVALE
Colored pigment
Dark brown called James’ pigment
- this species has the lowest incidence rate out of all the plasmodium
- Maximum parasite count is low
PLASMODIUM MALARIAE
Most immunogenic when the infection produces an immune complex deposition in the kidneys, which is associated with nephrotic syndrome
PLASMODIUM MALARIAE
PLASMODIUM MALARIAE
A. Malignant Tertian Malaria
B. Benign Tertian Malaria
C. Ovale Tertian Malaria
D. Quartan Malaria
E. Quotidian Malaria
D
PLASMODIUM MALARIAE
it’s growth and development are suppressed by
P. falciparum and P. vivax
PLASMODIUM MALARIAE
Colored Pigment
Brown black called Ziemann’s pigment
PLASMODIUM MALARIAE
Widepsread in?
Sub-Saharan Africa, Southeast Asia
- Predominant species in the world
- Can be life-threatening
P. falciparum
PLASMODIUM FALCIPARUM
AKA
A. Malignant Tertian Malaria
B. Benign Tertian Malaria
C. Ovale Tertian Malaria
D. Quartan Malaria
E. Quotidian Malaria
A. Malignant Tertian Malaria
PLASMODIUM FALCIPARUM
Pigment
Black (maurer’s pigment)
Life cycle
Agent
Plasmodium
Life cycle
Intermediate host
Human
Life cycle
Definitive host
Anopheles minimus
Life cycle
Clinical illness
Malaria
Life cycle
Vector
Infected Female Anopheles mosquito
Life cycle
Infective form
Sporozoites
however, trophozoites may also be infective
Life cycle
Reservoir
Infected Humans
Life cycle
Source of Infection
- mainly, saliva of infected female anopheles mosquito containing sporozoites
- infected blood of man containing trophozoites
Enumerate the mosquito spp.
- Aedes/albopictus
- Culex tarsalis
- Anopheles
- Female anopheles mosquitos
MOSQUITO SPP.
- Characterized by its sharp abdomen and striped legs
- bites during daytime
- breeds on stagnant water
Aedes/Albopictus
AEDES / ALBOPICTUS
Carries what diseases?
- Dengue
- Chikungunya
- Yellow fever
MOSQUITO SPP.
- blunt abdomen and striped legs
- bites during the night
- breeds on polluted water
Culex tarsalis
Culex tarsalis
Diseases
West nile virus
MOSQUITO SPP.
- dark blunt abdomen and dark legs
- bites before dawn and right after darkness
- breeds in clean, slow-moving water
- Holds the record for the deadliest animal, killing around 1 million people per year
Anopheles
Anopheles
Most common form
- A. minimus
- A. flavirostris
- A. maculatus
MOSQUITO SPP.
- Accounts for >95% of transmission globally
- body is dark brown to black in color
- When resting, the stomach of the mosquito points upward, rather than being even with the surrounding surface like most mosquitoes
- Most active before dawn and after dusk sets
- Clean, slow-moving water is considered prime
breeding grounds
Female Anopheles mosquitos
Female anopheles mosquitos
3 sections of the body
- head
- thorax
- abdomen
TOF. ASEXUAL reproduction occurs in the INTERMEDIATE host while SEXUAL reproduction occurs in the DEFINITIVE host.
T
HOST
TOF.
Asexual reproduction = humans
Sexual = the vector
T
HOST
- Asexual multiplication occurs
- Sexual differentiation occurs
INTERMEDIATE HOST
INTERMEDIATE HOST
When asexual multiplication occurs, this process is called schizogony which forms?
schizonts
INTERMEDIATE HOST
Sexual differentiation is also a process called?
gametogony
INTERMEDIATE HOST
In sexual differentiation, there’s a production of?
microgametocytes and
macrogametocytes
microgametocytes (male or female)
male
macrogametocytes (male or female)
female
INTERMEDIATE HOST
In sexual differentiation, there’s a presence of this which are infective to the definitive host
immature sex cells
DEFINITIVE HOST
TOF. Asexual multiplication and sexual differentiation occurs.
F (sexual multiplication only)
DEFINITIVE HOST
The sexual multiplication is also called?
Sporogony
DEFINITIVE HOST
There’s a production of what that is infective to the intermediate host
Sporozoites
SOURCE OF INFECTION
- Transfusion of infected blood
- transplacental
- infected needles
Trophozoites
SOURCE OF INFECTION
- Bite of infected female Anopheles mosquito
- Most common form of transmission
Sporozoites
INCUBATION PERIOD
P. falciparum
10-14 days
INCUBATION PERIOD
P. malariae
18 days - 6 weeks
INCUBATION PERIOD
P. vivax
10-14 days
INCUBATION PERIOD
P. ovale
10-14 days
pls study the life cycle of plasmodium
thx
i suggest yung module basahinniyo, mas detailed
MOSQUITO STAGE - SEXUAL STAGE
End product:
sporozoite
Summarize the development of sporogony
Zygote > Ookinete > Oocyst > Sporozoite
MOSQUITO STAGE - SEXUAL STAGE
- The mosquito will bite an infected human
- As it sucks the human’s blood, it will ingest the male and female gametocytes
- The gametocytes travel to the mosquito’s gut, where the male gametocyte will fertilize the female gametocyte
- Once the female gametocyte has been fertilized, it will now become a?
Zygote
MOSQUITO STAGE - SEXUAL STAGE
- After 6-8 hours, the zygote will mature into an invasive motile?
- From the gut of the mosquito, it will penetrate the epithelium of the gut and travel to the circulatory and lymphatic system of the mosquito
Ookinete
MOSQUITO STAGE - SEXUAL STAGE
- Once outside the gut, ookinete, it will transform into the?
- This will travel from the blood and lymph fluid into the salivary glands
- It will mature into a sporozoite
oocyst
MOSQUITO STAGE - SEXUAL STAGE
- End product of sporogony
- Once they are released from the mosquito, they are ready to infect humans
Sporozoite
MOSQUITO STAGE - SEXUAL STAGE
The whole sexual cycle usually takes?
8-30 days
TOF. After 6 days of being bitten with anopheles mosquito, it will develop into malaria.
F (Plasmodium has not yet reached 7 days of development)
HUMAN STAGE - ASEXUAL STAGE
4 stages
- Primary Exoerythrocytic / Pre-Erythrocytic / Hepatic
- Erythrocytic
- Gametogony
- Secondary Exoerythrocytic / Dormant
- Schizogony
HUMAN STAGE - ASEXUAL STAGE
Once the sporozoites reach the liver, it will transform to?
Sporozoite > Schizont > Merozoite
HUMAN STAGE - ASEXUAL STAGE
pls study the hepatic stage in detail
ok thanks
Primary Exoerythrocytic / Pre-Erythrocytic / Hepatic
how will the sporozoites enter the blood vessels once its embedded in the dermis?
traverse the epithelial cells and fibroblasts and enter the blood vessels
Primary Exoerythrocytic / Pre-Erythrocytic / Hepatic
Why do sporozoites prefer the liver?
Due to the interaction of the Plasmodium Circumsporozoite protein and Heparan Sulfate Proteoglycan of the liver
Primary Exoerythrocytic / Pre-Erythrocytic / Hepatic
The plasmodium will not immediately infect the parasite, they will first become?
transient vacuoles until they find a suitable cell to infect
Primary Exoerythrocytic / Pre-Erythrocytic / Hepatic
Once the suitable cell has been found they will transform into a?
parasitophorous vacuole and begin its maturation
Primary Exoerythrocytic / Pre-Erythrocytic / Hepatic
Once it fully matures, it will be released from the liver into the blood as?
hepatic merozoites
marks the end
ERYTHROCYTIC STAGE
STUDY IN DETS PLS
jfkjdckdfc
ERYTHROCYTIC STAGE
How does this begin?
Begins once the hepatic merozoites reach the blood
because only RBC has the receptor sites for merozoites
ERYTHROCYTIC STAGE
The erythrocytic merozoites remain and continue to mature in the?
RBC
ERYTHROCYTIC STAGE
what (2) occur in this stage
Schizogony and Gametogony
ERYTHROCYTIC STAGE
How does the stage develop?
step by step
Ring form > Young Trophozoite > Mature Trophozoite > Schizont > Merozoites
ERYTHROCYTIC STAGE
the primary morphological form that is found in RBC’s
ring form
ERYTHROCYTIC STAGE
- The presence of a cytoplasmic ring with a single chromatin dot
- At this point there is no visible cytoplasm
ring form
ERYTHROCYTIC STAGE
- Cytoplasmic ring with single chromatin dot
- There is the presence of a bluish cytoplasm, but it is barely conspicuous
Young Trophozoite
ERYTHROCYTIC STAGE
- Cytoplasmic ring with single chromatin dot, may become ameboid in shape
- Cytoplasm has become greater and more conspicuous
- Malarial pigments may begin to become
apparent at this stage - Changes in shape and size may also become apparent at this stage
Growing trophozoite
ERYTHROCYTIC STAGE
- Cytoplasmic ring with a single chromatin dot
- Cytoplasm is very conspicuous
Mature Trophozoite
ERYTHROCYTIC STAGE
- Once the nucleus begins to divide
- A mature form of this will contain merozoites which will be released into the bloodstream
Schizont
ERYTHROCYTIC STAGE
- Will lyse the RBC and be released into the bloodstream which can go into one of two directions
- Reinfect other RBCs or Differentiate into gametocytes (Gametogony)
Erythrocytic merozoite
GAMETOGONY
When does the life cycle restart?
once ingested by the anopheles mosquito
- Secondary Exoerythrocytic /Dormant schizogony
- Only occurs in P. vivax and P. ovale
- Sporozoites may remain dormant in the liver and may become active even after years of initial infection
- Once activated it will become a merozoite
- Responsible for relapse
HYPNOZOITE
Sporozoite or Trophozoite
Route of entry: Mosquito bite
Spo
Sporozoite or Trophozoite
Pre-erythrocytic schizogony: Absent
Tro (skips to erythrocytic stage)
Sporozoite or Trophozoite
Pre-erythrocytic schizogony: present
spo
Sporozoite or Trophozoite
Hepatomegaly: Occurs
Spo
sa tropho walay
Sporozoite or Trophozoite
Incubation period is long
Sporo
Sporozoite or Trophozoite
Incubation period is short
Tro
Sporozoite or Trophozoite
Exoerythrocytic schizogony: Absent
Tro (present kapag sporo)
Sporozoite or Trophozoite
Relapse may occur
Spo (does not occur sa tro)
Sporozoite or Trophozoite
Can be radically cured, no EE* forms
Tro (Schizonticidal drugs: in sporo, there’s no radical cure because of the presence of EE* forms)
○ No pre erythrocytic stage
○ No exoerythrocytic schizogony
○ Incubation period will be shorter
Trophozoite
Majority of the symptoms we can see in malaria
infections are due to (2)?
○ Erythrocyte changes
○ Host response
TOF. Both infected and uninfected RBCs can cause symptoms.
T
Familiarize the pathophysiology
thx uli
Pathophysiology
Infected RBCs result to?
4
purple
Toxic mediators
Phagocytosis
Anemia
Adhere to blood vessels
Uninfected RBC results to?
2
- Loss of deformability
- Clearance and destruction of uninfected RBCs
Erythrocytic stage of malarial infection
Uninfected and Infected RBCs
What stage invades the RBC?
merozoites
hepatic
TOF. Heme is toxic to RBC.
T
Heme degradation
What happens to the RBC when there’s a presence of heme?
2
○ RBC may die
○ Plasmodium will die alongside the RBC
HEME DEGRADATION
The plasmodium will convert heme to a non-toxic material called?
hemozoin pigment
enumrate the hemozoin pigments
○ Maurer’s
○ Schuffner’s
○ Ziemann’s
○ James’s
When RBC’s become prone to sticking to each other it will lead to?
blockage of capillaries and
venules
ALTER RBC MEMBRANE
RBC will be more
A. antigenic
B. less deformable
C. more irregular in shape.
D. AOTA
D
ALTER RBC MEMBRANE
When infected RBCs compact with uninfected RBCs
Rosette formation
ALTER RBC MEMBRANE
When infected RBCs compact with other infected RBCs
Agglutination
HOST RESPONSE
Which does not belong:
A. Activation of non-specific defense mechanism of the Spleen
B. Removal infected RBCs
C. Removes damaged ring form parasites
D. RBCs return to the circulation with shortened survival
E. Escaped RBCs are destroyed when Schizont ruptures
B (Removal of parasitized and uninfected RBCs)
the following are actual host response
- Non-specific immunity
ACQUIRED IMMUNITY
TOF. Multiple infections of Malaria do not confer lifelong immunity.
T
CLINICAL PRESENTATION
densities of parasitic blood for symptomatic stage of infection to begin
more than 50/uL
FEBRILE ATTACK
Periodic attacks of fever due to release of toxic metabolites of the parasite formed during each?
erythrocytic schizogony
release of merozoites = fever
FEBRILE ATTACK
Malarial fever maintains a specific pattern except in?
Falciparum
Febrile attack
Stages of malaria (3)
Cold, hot and sweating stage
Stages of malaria
■ Lasts from 15 mins to 1 hr
■ Corresponds to the release of
merozoites
■ Dividing generation of parasites
rupture their host RBCs and escape
into the blood
Cold stage
Stages of malaria
■ Lasting 1 to 4 hrs
■ Spiking fever that frequently
reaches 40 deg celsius or more
■ Parasites invade new RBCs
Hot stage
Stages of malaria
Fever spontaneously comes down
over several hours and the patient sweats profusely
Sweating stage
PATTERN OF FEVER
Subtertian/Malignant tertian, Benign tertian, Ovale tertian
48hrs
PATTERN OF FEVER
Quotidian malaria
24 hrs
PATTERN OF FEVER
Quartan Malaria
72 hours
Can be normocytic, hypochromic, or microcytic hypochromic type
ANEMIA
ANEMIA
○ Shortened RBC life span
○ Erythrophagocytosis by macrophages
○ Complement-mediated hemolysis
○ Loss of complement regulatory proteins from the RBC surface
increased destruction
ANEMIA
○ Morphological abnormalities in red cell precursors
○ Dyserythropoiesis
○ Inadequate reticulocyte production
○ Effect of parasite factors (hemozoin, malaria toxins)
○ Effects of inflammatory cytokines
○ Inadequate EPO production
DECREASED PRODUCTION
DECREASED PRODUCTION or INCREASED DESTRUCTION
○ Morphological abnormalities in red cell precursors
○ Dyserythropoiesis
○ Inadequate reticulocyte production
DECREASED PRODUCTION
DECREASED PRODUCTION or INCREASED DESTRUCTION
○ Complement-mediated hemolysis
○ Loss of complement regulatory proteins from the RBC surface
increased
DECREASED PRODUCTION or INCREASED DESTRUCTION
○ Shortened RBC life span
○ Erythrophagocytosis by macrophages
Increased
DECREASED PRODUCTION or INCREASED DESTRUCTION
○ Inadequate reticulocyte production
○ Effect of parasite factors (hemozoin, malaria toxins)
○ Effects of inflammatory cytokines
○ Inadequate EPO production
decreased
Clinical presentation
- Due to enhanced immune response to the plasmodium
- Aberrant immune response to antigenic stimulation
HYPERREACTIVE MALARIAL SPLENOMEGALY
Associated with macroglobulinemia, the production of cytotoxic IgM antibodies to CD8+ lymphocytes, antibodies to CD5+ lymphocytes, and an increase in
the ratio of CD4+ to CD8+ cells
HYPERREACTIVE MALARIAL SPLENOMEGALY
Stimulated lymphoid hyperplasia and clearance
activity
HYPERREACTIVE MALARIAL SPLENOMEGALY
Enumerate complications
- CEREBRAL MALARIA
- BLACKWATER FEVER
- QUARTAN MALARIAL NEPHROPATHY
➢ Most common cause of coma and death in falciparum malaria
➢ Many parasitized cells can be found in the capillaries of the brain and in the late stages, hemorrhaging from small blood vessels can occur
CEREBRAL MALARIA
The formation of this could be the cause of cerebral malaria, as there could be a blockage to the blood flow of the brain, mimicking a stroke
rosette formations and agglutination
- Patients may present with impaired consciousness, delirium, and/or seizures
- Usual presentation is diffuse, symmetric encephalopathy, focal neurological signs are present
CEREBRAL MALARIA
➢ Rare but acute condition in which there is a rapid and massive intravascular hemolysis of both parasitized and non-parasitized RBCs
➢ Results in hemoglobinemia and hemoglobinuria
➢ Urine appears dark-red to brown-black due to the presence of free hemoglobin
➢ Can occur in non-immune adults with severe falciparum malaria
➢ Previously thought to be a complication of quinine treatment
BLACKWATER FEVER
➢ Nephrotic syndrome
➢ Chronic or repeated infections with P. malariae may
cause insoluble immune complex injury to glomerular basement membrane, resulting in nephrotic syndrome
➢ Characterized by albuminuria, low blood protein, generalized edema, asymptomatic proteinuria, renal failure, anemia, hepatomegaly, and hepatosplenomegaly
➢ Usually there is no treatment, as it responds poorly to antimalarial agents or glucocorticoids and cytotoxic drugs
QUARTAN MALARIAL NEPHROPATHY
Which is correctly paired.
QMN = Hemoglobinemia
Cerebral = Rosette formations
Black water fever = Coma
Cerebral = = Rosette formations
Diagnosis
- Demonstration of malarial antigen, antibody, or nucleic acid sequence
- Parasite itself is not demonstrated
Indirect
Diagnosis
- Demonstration of malarial parasite
- Through this method identification is possible
Direct
Enumarate direct diagnosis
PBS (Thick and Thin film)
Gold standard in diagnosis of malarial infection
Peripheral blood smear (PBS)
PBS
stain
Giemsa
PBS
Best TIME for specimen collection
Prior to fever
TOF. No parasites will be demonstrated if the timing in collecting specimen is during the peak of fever.
T
kaka-release lang raw kasi sa RBC
Thick or Thin
- dehemoglobinized* (lysed) RBCs
- used in low parasitemia
- More efficient detection of parasites (increased sensitivity)
- Species can not be diagnosed
Thick
Thick or thin
- Consists of blood spread in a layer such that the thickness decreases progressively toward the feathered edge
- Fixed in anhydrous methanol
- Can not be used in low parasitemia
- Species can be diagnosed
Thin
➢ Dried thoroughly and stained without fixing
➢ Multiple layers of erythrocytes lay on top of one another and are lysed during the staining procedure, the thick film has the advantage of concentrating the
parasites
➢ Both parasites and WBCs are counted
➢ Minimum of 200 WBCs should be counted under oil immersion
➢ Before thick smear is judged negative, 100-200 fields should be examined
Thick blood smer
TOF. Clinically, if there is presence of >50,000/uL parasites in the blood, the patient is at increased risk of severe malaria
F (>100,000/uL)
Find the incorrect finding
vivax = Enlarged infected RBCs
malariae = band form
ovale = polymorphism
falciparum = multiple infection
Ovale (should be fimbriated or ragged RBCs)
Enumerate the PCR used (4)
- Conventional
- Nested
- Real-time
- Multiplex
○ Amplifies specific regions of the malaria parasite DNA, allowing for the detection of different plasmodium spp.
○ Requires gel electrophoresis to visualize the amplified DNA
Conventional PCR
there is visible pigment in >20 of parasites or of phagocytosed pigment in >5 of PMNs (WBC)
A. average prognosis
B. good prognosis
C. acute prognosis
D. worse prognosis
D
RAPID DIAGNOSTIC TEST
TARGET ANTIGEN: Plasmodium falciparum HRP2
PURPOSE: Detecting P. falciparum
HISTIDINE-RICH PROTEIN 2 (HRP2)
TARGET ANTIGEN: Aldolase enzyme, present in all malaria species
PURPOSE: Typically used as a pan-malaria test to detect all malaria species, often combined with HRP2 of pLDH to differentiate species
ALDOLASE-BASED TEST
ADVANTAGE: Can detect all species of malaria, providing a broad diagnostic tool
LIMIT:
* Generally lower sensitivity compared to HRP2 and pLDH tests
* Not commonly used as a standalone test due to its lower sensitivity specificity
ALDOLASE-BASED TEST
RAPID DIAGNOSTIC TEST
ADVANTAGES:
* High sensitivity for P. falciparum, especially in high-transmission areas
* Long-lasting positive results, which can help track ongoing infections
LIMITATION:
* Can not detect non-falciparum species
* Persistence of HRP2 antigen in the blood can lead to false-positive results even after successful treatment
* HRP2 gene deletions in some P. falciparum strains can lead to false-negative results
HISTIDINE-RICH PROTEIN 2 (HRP2)
RAPID DIAGNOSTIC TEST
TARGET ANTIGEN: Plasmodium lactate dehydrogenase (pLDH), which is produced by all malaria species
PURPOSE: Can be designed to detect all malaria species (pan-specific) or to differentiate between P. falciparum and non-falciparum species
PLASMODIUM LACTATE DEHYDROGENASE(PLDH)
ADVANTAGE:
* Can distinguish between different species of malaria (e.g. falciparum vs non-falciparum)
* pLDH levels decrease rapidly after successful treatment, making it useful for monitoring treatment efficacy
LIMITATION:
* Generally less sensitive than HRP2-based tests for detecting P. falciparum
* pLDH levels drop quickly, which can result in false negatives if blood samples are taken too soon after treatment
PLASMODIUM LACTATE DEHYDROGENASE(PLDH)
TARGET ANTIGEN: Detect multiple antigens, usually a combination of HRP2 and pLDH or HRP2 and Aldolase
PURPOSE: Designed to provide more comprehensive testing by detecting both P. falciparum and non-falciparum species
COMBINATION RDTS (MULTI-ANTIGEN TEST)
ADVANTAGE:
* Improved diagnostic accuracy by combining multiple antigens
* can differentiate between falciparum and other species while detecting mixed infections
* useful in areas where multiple malaria species are prevalent
LIMIT:
* Higher cost compared to single-antigen RDTs
* Increased complexity may require more training for health workers
COMBINATION RDTS (MULTI-ANTIGEN TEST)
PCR
○ Involves using two rounds of PCR to increase sensitivity and specificity
○ Especially used for detecting low parasitemia levels or mixed infections
Nested
PCR
○ Quantifies the parasite DNA in real-time
using fluorescent dyes or probes
○ Provides both qualitative and quantitative results, offering high sensitivity and rapid
results
Real time PCR
PCR
○ Allows for the simultaneous detection of multiple malaria species in a single reaction by amplifying different target DNA sequences using multiple sets of primers
Multiplex
PCR
➢ Amplifies DNA at a constant temperature, avoiding the need for thermal cycling as in PCR
➢ It is designed to be simpler and faster, with results typically obtained in less than an hour
LOOP-MEDIATED ISOTHERMAL AMPLIFICATION
➢ Amplifies RNA rather than DNA
○ RNA unstable so it is converted to DNA
➢ Useful for detecting the presence of viable parasites, as RNA is less stable than DNA and is only present in metabolically active parasites
QT NASBA
➢ Variant of PCR that first converts parasite RNA into
a complementary DNA (cDNA) using reverse
transcription, followed by PCR amplification
➢ Often used to detect the presence of RNA transcripts, indicating active infections
RT-PCR
➢ Post-PCR analysis method used to identify genetic variations in DNA of malaria parasites
➢ Detects differences in the melting temperature of DNA, which can indicate different species or genotypes
HIGH-RESOLUTION MELTING (HRM) ANALYSIS
➢ Involves sequencing the entire genome or specific regions of the malaria parasite DNA
➢ Provides detailed information about the genetic makeup, drug resistance mutations, and transmission dynamics of malaria parasites
NEXT-GENERATION SEQUENCING (NGS)
ADVANTAGE:
High sensitivity and specificity
Faster results (within an hour) and easier to perform -
does not sophisticated infrastructure or highly trained personnel require laboratory
DISADVANTAGE
Less versatile in differentiating between all malaria species
The colorimetric detection method used in some LAMP assays may be prone to subjective interpretation
LOOP-MEDIATED ISOTHERMAL AMPLIFICATION
Advantage (A): High sensitivity, especially for detecting low levels of parasites
Can differentiate between active infections (as it detects RNA) and past infections (where DNA may still be present)
- Useful for monitoring treatment efficacy and detecting recrudescence or relapse
Disadvantage (D): Requires specialized equipment and reagents, making it less suitable for routing use in resource-limited settings
- RNA degradation can be a challenge, requiring careful sample handling and storage
QT-NASBA
A: High sensitivity for detecting low parasite loads - Provides information about the viability and stage of the parasite, which can be useful in research and monitoring treatment efficacy
D: Requires more complex protocols and equipment compared to conventional PCR
- RNA handling and stability can be a limiting factor
RT PCR
A: Rapid and cost-effective for species identification and genotyping after initial PCR amplification
Can identify mutations associated with drug resistance
D: Requires specialized equipment for melting analysis
Less sensitive than some other molecular methods for detecting very low parasite densities
HIGH-RESOLUTION MELTING (HRM) ANALYSIS
A: Extremely high resolution for detecting subspecies, diversity, and resistance mutations
Valuable for research, epidemiological studies, and understanding transmission patterns
D: High cost, complex data analysis, and the need for advanced bioinformatics tools
Not practical for routine diagnostics in most clinical settings
NEXT-GENERATION SEQUENCING (NGS)
SEROLOGIC METHODS
- Detects specific antibodies (IgM, IgG) or antigens associated with malaria infection in blood sample
- Antibody detection: measures the presence of antibodies (IgM, IgG) against malaria antigens to indicate current or past infection
ELISA
SEROLOGIC METHODS
A: High sensitivity and specificity, especially for detecting antibodies; Useful for epidemiological studies to assess exposure and transmission rates
D: Cannot distinguish between active and past infections when detecting antibodies; Requires specialized laboratory equipment and trained personnel; Antigen detecting ELISA may not be sensitive enough to detect low-level parasitemia
ELISA
SEROLOGIC METHODS
- Detects antibodies against malaria parasites in a patient’s serum
- Involves placing parasite antigens on a slide, adding patient serum, and then adding a fluorescent-labeled secondary antibody that binds to any antibodies in the patient serum
- If antibodies are present, they will bind to the parasite antigens, and the fluorescent marker will be visible under a fluorescent microscope
*
INDIRECT FLUORESCENT ANTIBODY TEST (IFA)
SEROLOGIC METHODS
A: High sensitivity for detecting antibodies against all plasmodium species; Useful in epidemiological surveys to determine past exposure to malaria
D: Cannot distinguish between current and past infections; Requires a fluorescent microscope, skilled personnel, and is time-consuming; Less commonly used in routine diagnostics due to complexity and cost
INDIRECT FLUORESCENT ANTIBODY TEST (IFA)
SEROLOGIC METHODS
➢ Highly sensitive technique that uses radioactively labeled antigens or antibodies to detect specific antibodies in a blood sample
➢ Involves mixing the patient’s serum with radio-labeled malaria antigens and then measuring the radioactivity to determine the presence and quantity of antibodies
RADIOIMMUNOASSAY (RIA)
SEROLOGIC METHODS
A: High sensitivity and specificity for detecting antibodies against malaria
B: Requires equipment, materials, personnel
specialized radioactive and trained; Not commonly used due to safety concerns related to radioactivity and the need for specialized disposal of radioactive waste
RADIOIMMUNOASSAY (RIA)
SEROLOGIC METHODS
➢ Detects antibodies by observing whether the complement system is activated when patient serum is mixed with specific malaria antigens
➢ Based on the principle that if specific antibodies are present, they will bind to the antigen and fix the complement, preventing lysis of RBCs added to the mixture
COMPLEMENT FIXATION TEST
SEROLOGIC METHODS
A: Can provide evidence of past exposure to malaria
D: Less sensitive and specific compared to more modern techniques like ELISA and IFA; Time-consuming and requires careful handling and precise interpretation
COMPLEMENT FIXATION TEST
SEROLOGIC METHODS
Enumerate Primary Prophlaxis
- CHLOROQUINE
- ATOVAQUONE
- DOXYCYCLINE
- MEFLOQUINE
PRIMARY PROPHYLAXIS
1-2 weeks before leaving, take weekly while away, and then take once weekly for 4 weeks after returning home
CHLOROQUINE
PRIMARY PROPHYLAXIS
Once daily started 1-2 days before travel, for duration of stay, and then for 1 week after returning home
ATOVAQUONE
PRIMARY PROPHYLAXIS
Taken 1-2 days before travel, daily while away, and then up to 4 weeks after returning
DOXYCYCLINE
PRIMARY PROPHYLAXIS
Given once weekly
MEFLOQUINE
SECONDARY PROPHYLAXIS
Primaquine for (what plasmodia sp.)
P. vivax or P. ovale
SECONDARY PROPHYLAXIS
Primaquine daily for how many days after departure from the malarious area
14 days
TOF. A good malaria treatment should be able to cover all the stages of the parasite.
T
TREATMENT
Hepatic stage
Tissue schizonticides
TREATMENT
Erythrocytic stage
Blood schizonticides
TREATMENT
Gametogony
gametocides
only drug that covers all stages
primaquine
first pre-erythrocytic RTS vaccine was created in
1987 and by 2019
was the first malaria vaccine approved for widespread use
In 2021, RTS vaccine
TOF. Patients with sickle cell TRAIT are conferred protection from severe malaria due to the presence of the gene. While, patients with sickle cell DISEASE are not conferred protection from malaria, they are still vulnerable to malaria.
T
➢ First line of treatment for uncomplicated and severe P. falciparum malaria
➢ Cannot be bought in any drugstore ➢ 3-7 days, to cover 2 asexual cycles ➢ Can only be acquired from DOH
○ This is to control the resistance of the parasite to the drug
➢ Ensures that only a small fraction of parasites remain for clearance by the partner drug
➢ Monitor clinical response and check parasite density every 12-24 hours
ARTEMETHER-LUMEFANTRINE (AL)
➢ Second line of treatment if AL is not available ➢ Or if the patient is allergic to AL
QUININE + TETRACYCLINE / CLINDAMYCIN
➢ To prevent relapse in P.vivax or P.ovale infection ➢ 14 days of treatment to target hypnozoite
PRIMAQUINE
➢ Called Mosquirix
➢ Prevents only around 50-60% of infections
➢ First malaria vaccine approved for public use in 2021
➢ Recombinant vaccine, consisting of the P. falciparum circumsporozoite protein (CSP) from the pre-erythrocytic stage
○ Different from other vaccines that elicit immune responses
○ Targets the proteins in sporozoites
➢ Delivered intramuscularly
➢ First dose is given at 5 months of age
➢ The first 3 doses are administered monthly, and the
third should be completed by 9 months of age
➢ Reduces hospital admission from severe malaria by
around 30%
RTS.S / AS01
➢ Most effective malaria vaccine with 77% efficacy shown in initial trials
➢ Novel pre-erythrocytic malaria vaccine with a similar mechanism of action to RTS.S, but designed to induce increased Anti-Circumsporozoite Protein antibody and lower Anti-Hepatitis B surface antigen antibody responses
➢ Given intramuscularly at 3 doses, 4 weeks apart
➢ Malaria vaccine can be used for the prevention of P. falciparum malaria in children living in regions with
moderate to high transmission
R21 / MATRIX-M
