(M) Plasmodium (lecture-based) Flashcards by ASHLEY JARED DEFENSOR

Phylum

Sporozoa (formerly known as Apicomplexa)

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Class

Sporozea

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Subclass

Coccidia

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Superorder

Eucoccidea

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Order, Suborder and Family of Plasmodium

Haemosporida, Aconoidna, Haemospiridae

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The malaria antigen was detected in? dates back from 3200-1304 BC

Egyptian remains

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Indian writings of the Vedic period (1500 - 800 BC) called malaria the?

King of diseases

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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

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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),

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He mentions Malaria in The Iliad, as foes Aristophanes in The Wasps, and Aristotle, Plato, and Sophocles

Homer

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He described the disease in a medical text in the 4th or 5th century BC

Hippocrates

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This person may have died of a Malaria infection at age 30

Alexander the great

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TOF. The greek physician, Torti, coined the term Malaria in 1718.

F (italian)

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Italian word Malaria which means?

Bad air

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Roman physicians believed that the disease was caused by?

malignancies in the swamp air

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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

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What did Laveran discovered?

protozoan plasmodium

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He found out that the plasmodium is the causative agent of Malaria

CHARLES LOUIS ALPHONSE LAVERAN

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Over how many species of plasmodium have been described?

200

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Plasmodium species are limited to five

Plasmodium falciparum
P. ovale
P. vivax
P. malariae
P. knowlesi

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still considered a zoonotic plasmodium, i.e. it is a disease of animals such as Macaque monkeys

Plasmodium knowlesi

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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

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TOF. In 2023, the Department of Health (DOH) reported a decrease in the cases of Malaria

F (increase)

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only province in the Philippines where Malaria is endemic

Palawan

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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) ## Footnote 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

# 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.

# 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

# 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.

1. Aedes/albopictus 2. Culex tarsalis 3. Anopheles 4. 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.

# HOST TOF. Asexual reproduction = humans Sexual = the vector

# 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 ## Footnote 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 ## Footnote marks the end

# ERYTHROCYTIC STAGE STUDY IN DETS PLS

jfkjdckdfc

# ERYTHROCYTIC STAGE How does this begin?

Begins once the hepatic merozoites reach the blood ## Footnote 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 ## Footnote 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.

Familiarize the pathophysiology

thx uli

# Pathophysiology Infected RBCs result to? | 4 ## Footnote 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 ## Footnote hepatic

TOF. Heme is toxic to RBC.

# 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

# 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) ## Footnote the following are actual host response

* Non-specific immunity

ACQUIRED IMMUNITY

TOF. Multiple infections of Malaria do not confer lifelong immunity.

# 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 ## Footnote 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 ## Footnote 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)

1. Conventional 2. Nested 3. Real-time 4. 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

# 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.

# 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.

➢ 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

(M) Plasmodium (lecture-based) Flashcards

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