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Questions and Answers
What is a limitation of serodiagnosis in diagnosing malaria?
What is a limitation of serodiagnosis in diagnosing malaria?
What is the primary advantage of using Rapid Diagnostic Tests (RDT) for malaria diagnosis?
What is the primary advantage of using Rapid Diagnostic Tests (RDT) for malaria diagnosis?
Which of the following statements correctly describes the use of PCR in malaria diagnosis?
Which of the following statements correctly describes the use of PCR in malaria diagnosis?
Which combination of Plasmodium species correctly matches simian and human types?
Which combination of Plasmodium species correctly matches simian and human types?
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Why might serodiagnosis be particularly useful from an epidemiological perspective?
Why might serodiagnosis be particularly useful from an epidemiological perspective?
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What is one of the principles of malaria prevention and control for travelers to endemic areas?
What is one of the principles of malaria prevention and control for travelers to endemic areas?
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Which of the following methods is NOT included in the malaria prevention strategies?
Which of the following methods is NOT included in the malaria prevention strategies?
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What is suggested as a protective measure for individuals in malarious areas?
What is suggested as a protective measure for individuals in malarious areas?
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Which of the following is NOT part of the WHO's ABCD recommendations for malaria protection?
Which of the following is NOT part of the WHO's ABCD recommendations for malaria protection?
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Which of the following best describes the use of vaccines in malaria prevention?
Which of the following best describes the use of vaccines in malaria prevention?
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What is a major clinical manifestation of blackwater fever?
What is a major clinical manifestation of blackwater fever?
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Which of these complications is not associated with blackwater fever?
Which of these complications is not associated with blackwater fever?
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Which condition is characterized by high continuous fever and is associated with multiple organ failure?
Which condition is characterized by high continuous fever and is associated with multiple organ failure?
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What causes hypoglycemia in malaria patients, particularly during pregnancy?
What causes hypoglycemia in malaria patients, particularly during pregnancy?
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What is the main complication associated with P.malariae infections?
What is the main complication associated with P.malariae infections?
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What is the primary characteristic of Nested PCR?
What is the primary characteristic of Nested PCR?
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Which PCR method is known for real-time monitoring of DNA amplification?
Which PCR method is known for real-time monitoring of DNA amplification?
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Which technique is used for confirming malaria diagnosis through laboratory investigations?
Which technique is used for confirming malaria diagnosis through laboratory investigations?
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What is a major advantage of using LAMP for DNA amplification?
What is a major advantage of using LAMP for DNA amplification?
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What is a common feature of algid malaria?
What is a common feature of algid malaria?
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What causes acute renal failure in severe cases of malaria?
What causes acute renal failure in severe cases of malaria?
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Which factor significantly affects the choice of antimalarial drugs for treatment?
Which factor significantly affects the choice of antimalarial drugs for treatment?
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What is the main purpose of treating malaria with specific antimalarial drugs?
What is the main purpose of treating malaria with specific antimalarial drugs?
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What is the primary characteristic of cerebral malaria caused by P. falciparum?
What is the primary characteristic of cerebral malaria caused by P. falciparum?
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Which of the following complications is most severe in malaria?
Which of the following complications is most severe in malaria?
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What is a direct consequence of the obstruction caused by sequestrated RBCs in cerebral malaria?
What is a direct consequence of the obstruction caused by sequestrated RBCs in cerebral malaria?
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How do late stage schizonts of P. falciparum contribute to hemolytic anemia?
How do late stage schizonts of P. falciparum contribute to hemolytic anemia?
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What mechanism is involved in the multi-factorial process leading to cerebral malaria?
What mechanism is involved in the multi-factorial process leading to cerebral malaria?
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Which statement best describes the role of the adhesive proteins secreted by P. falciparum?
Which statement best describes the role of the adhesive proteins secreted by P. falciparum?
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What is one of the major consequences of the microvascular obstruction in cerebral malaria?
What is one of the major consequences of the microvascular obstruction in cerebral malaria?
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In which condition does P. falciparum lead to coma and potentially death?
In which condition does P. falciparum lead to coma and potentially death?
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What is the primary advantage of using a thick blood smear for diagnosing malaria?
What is the primary advantage of using a thick blood smear for diagnosing malaria?
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Which type of blood smear allows for the identification of the malaria parasite species?
Which type of blood smear allows for the identification of the malaria parasite species?
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In the case of P.vivax infection, what morphological change occurs in red blood cells?
In the case of P.vivax infection, what morphological change occurs in red blood cells?
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What is a distinguishing feature of P.falciparum gametocytes?
What is a distinguishing feature of P.falciparum gametocytes?
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What type of stippling is associated with P.vivax infections?
What type of stippling is associated with P.vivax infections?
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In P.malariae infections, which of the following is observed in the ring-form trophozoite?
In P.malariae infections, which of the following is observed in the ring-form trophozoite?
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What is the schizont structure in P.vivax characterized by in terms of merozoite numbers?
What is the schizont structure in P.vivax characterized by in terms of merozoite numbers?
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What happens to red blood cells in thick blood smears during the microscopy process?
What happens to red blood cells in thick blood smears during the microscopy process?
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Study Notes
Malaria-2 Lecture Outline
- Malaria-2 lecture is presented by Dr. Nantha Kumar Jegaprakasam, PhD, from the Center for Toxicology and Health Risk Studies (CORE), Faculty of Health Science (FSK), Universiti Kebangsaan Malaysia (UKM).
Lecture Outline
- Subtopic 6: Complications of malaria
- Subtopic 7: Laboratory diagnosis (microscopy & molecular techniques)
- Subtopic 8: Treatment for malaria
- Subtopic 9: Prevention & control for malaria
Complications of Malaria
-
Cerebral malaria:
- Most severe complication
- Fatal, featuring headache, neck stiffness, disorientation, coma, and death
- Multi-factorial process involving sequestration, inflammation, and endothelial dysfunction in the brain's microvasculature, leading to coma
- Late stage Plasmodium falciparum schizonts secrete proteins forming knobs on the surface of red blood cells (RBCs)
- Knobs promote adhesion of infected RBCs to other RBCs and capillary endothelial cells, blocking cerebral microvasculature, leading to anoxia, ischaemia, and haemorrhage.
-
Hemolytic anemia:
- Destruction of large numbers of RBCs via complement-mediated and autoimmune hemolysis
- Impaired erythropoiesis in the bone marrow
- Increased clearance of parasitized and non-parasitized RBCs by the spleen
- Failure of the host to recycle iron bound in hemozoin pigment
- Antimalarial therapy in G6PD deficient patients
-
Blackwater fever:
- Seen in falciparum malaria, particularly with repeated infections and insufficient quinine treatment
- Clinical manifestations including bilious vomiting, prostration, and passage of dark red or black urine (blackwater)
- Pathogenesis due to massive intravascular hemolysis caused by anti-erythrocyte antibodies, resulting in hemoglobinuria
- Potential complications include renal failure, acute liver failure, and circulatory collapse
-
Gastrointestinal syndrome:
- Characterized by jaundice, hepatomegaly, epigastric pain, nausea, vomiting, and diarrhea
-
Algid malaria:
- Adrenal insufficiency-like syndrome leading to shock, low blood pressure, rapid pulse, difficulty breathing and hemoconcentration.
-
Hypoglycemia:
- Especially during pregnancy, potentially causing neurological problems like restlessness, dyspnea, convulsions, and loss of consciousness
- Possible factors include liver glycogen depletion from decreased oral intake, glucose consumption by the parasite, and the hypoglycemic effect of Tumor Necrosis Factor (TNF).
-
Pulmonary oedema (PO):
- Increased TNF level may cause pulmonary oedema.
-
Acute renal failure:
- Severe cases potentially due to tubular necrosis.
-
Septicemic malaria:
- High fever characterizes it
- Dissemination of the parasite causes multi-organ failure
- High mortality rate (80%)
Complications (P. vivax & P. ovale)
- Develop serious disease, but complications are rare.
Complications (P. malariae)
- Mild infection, often becoming chronic.
- Main complication is nephrotic syndrome.
- Immune complexes may lead to structural glomerular damage and nephrotic syndrome.
Complications (P. knowlesi)
- Single or multi-system failure, potentially including acute respiratory distress syndrome, acute renal failure, hepatic dysfunction, metabolic acidosis, hypoglycemia, hypotension, and thrombocytopenia/lymphopenia
Recrudescence & Relapse
- Recrudescence: Persistence of parasites at a low level in circulation, occurring within a few weeks to months of a prior attack; seen in P. falciparum and P. malariae
- Relapse: Reactivation of hypnozoites in the liver; occurs weeks to years after the primary attack; seen in P. vivax and P. ovale
Laboratory Diagnosis
- History from the patient and their signs/symptoms
- Laboratory investigations (blood films) confirming diagnosis
- Blood smears stained with Romanowsky stains (Giemsa/Field stain) show bluish cytoplasm and reddish nuclear chromatin.
- Thin and thick blood films are used.
Investigating Suspected Malaria
- Blood films should be done immediately. Repeat another sample if initial results are negative, especially at peak fever.
- Full blood count (FBC) may show relative lymphopenia or neutrophilia (suggestive of secondary infection or severe disease) and thrombocytopenia (over 90% of non-immune patients).
- Blood Urea and Serum Electrolytes (BUSE), and CRP level check for low sodium, calcium, and albumin, which usually resolve with treatment. CRP is raised.
- Liver profile and blood glucose may reveal abnormalities (bilirubin, liver enzymes) which may indicate other conditions, particularly in cases of high parasitemia or quinine treatment
- Sodium, calcium and albumin are often low, resolving with treatment
Demonstration of Parasite by Microscopy
- Two types of smears are prepared from peripheral blood: thin and thick blood smears.
Thick Blood Film
- Main use is detecting infection due to higher blood volume
- Cannot identify species due to red blood cell lysis.
Thin Blood Film
- Identifies species due to lack of red blood cell lysis
- Allows study of shape and size of infected red blood cells.
Diagnosis: Identification of Malaria Parasite
- Size of infected RBC: Enlarged in P. vivax (rarely)
- Shape of infected RBC: Oval in P. ovale; Enlarged in general in symptomatic malaria cases
- Shape of gametocyte: Banana or crescent shape in P. falciparum; round in other species.
- Shape of trophozoite in RBC: Band form (P. malariae & P. knowlesi); ring form (other species).
- Stippling (dots) in RBCs is species-specific.
Overall Morphological Characteristics of Malaria Parasites in Blood
- Charts and diagrams of various malaria species' morphology presented.
P. falciparum
- Ring Form (early trophozoite)
- Mature Schizont
- Microgametocyte
- Macrogametocyte
Diagnosis: (Further P. falciparum characteristics)
- Trophozoites display small ring forms within the red blood cells.
- Accole form: Trophozoites in the RBC
P. vivax
- Ring Form (early trophozoite)
- Immature Schizonts: Cytoplasmic Material, Chromatin mass
- Microgametocyte: Halo/colorless to pale
P. vivax Characteristics
- "Reticulocyte" (immature RBC) only;
- Schuffner's dots
P. malariae
- Ring form (early trophozoite)
- Mature Schizont
P. malariae Description
- Single chromatin dot
- Cytoplasm ring; thicker than P. falciparum.
- Bird's-eye forms may occasionally appear
- No enlargement of infected RBCs
P. ovale
- Ring form trophozoites: Usually a single chromatin dot, but double dots are possible in some cases.
Specie Differentiation
- Charts distinguishing various species based on RBC shape, stippling, trophozoite shape, chromatin, and developmental stage features (i.e., schizont counts).
Serodiagnosis
- Useful for epidemiological studies to assess population immunity
- Can identify infected donors, particularly in transfusion malaria
- Less useful in acute cases due to antibody presence.
- Indirect hemagglutination (IHA), indirect fluorescent antibody (IFA), and enzyme-linked immunosorbent assay (ELISA) are the tests used.
Rapid Diagnostic Tests (RDTs)
- Detect circulating parasite antigens in blood.
- Supplementary to microscopy for situations where expertise or time are limited.
- Results should always be interpreted alongside microscopy readings, completed by experienced technicians.
Molecular Diagnosis
- Whole blood in EDTA or dried blood spot on filter paper are preferred for PCR analysis.
- PCR is suitable when parasite is absent in blood film, in mortality cases and cases with P. malariae appearance.
Morphological Similarities between Human & Simian Plasmodium
- Charts showing comparable morphological characteristics of human and simian malaria parasites.
Molecular Detection Methods for Simian Plasmodium
- Nested PCR, Real-time PCR, Single step PCR, and LAMP methods for diagnosis.
Treatment for Malaria
- Specific antimalarial drug therapy used to terminate parasitaemia, prevent relapse, recrudescence and transmission, and for prophylaxis
- Drug selection depends on country policies, types of malaria infection, and drug resistance
Supportive Treatment
- Aimed at relieving symptoms like fever, rehydration, and blood replacement for severe anemia.
- Also includes control of convulsions using anticonvulsant drugs, and treatment of DIC (disseminated intravascular coagulation)
Anti-malarial Drugs
- Drug selection influenced by parasite species, strain, and stage.
- Tissue schizonticides (e.g., primaquine) act on tissue schizonts to prevent symptomatic malaria
- Blood schizonticides (e.g., chloroquine, quinine) act on infected red blood cells (RBCs), treating malaria and used for prophylaxis.
- Gametocidal agents act on gametocytes (e.g., primaquine).
- Artemisinin-based combination therapy (ACT) is currently recommended for P. falciparum treatment. ACTs provide high efficacy, fast action, and reduced resistance to developing
Specific Treatments (Further Details)
- Artemisinin-based combination therapy (ACT) is recommended; various drugs such as dihydroartemisinin, artesunate, and artemether.
- Chloroquine is a commonly used first-line treatment for P. vivax and P. ovale.
- Primaquine is used for liver stage parasites of P. vivax.
Quinine and Related Drugs
- Quinine and related drugs as alternative treatments for multi-drug resistant strains
- Mefloquine, and halofantrine and Qinghaosu
Prevention & Control
- Awareness about risk, incubation period, and symptoms
- Bite prevention (avoid mosquitoes, especially during dawn and dusk)
- Chemoprophylaxis (using antimalarial drugs when appropriate)
- Diagnosis (seeking medical help if fever develops a week after exposure)
- Treatment/Treatment of cases, vector control (eliminating standing water, insecticide spray), personal protection (bed nets, insect repellant, long sleeves), and vaccine development
- WHO's ABCD of Malaria Prevention measures highlighted
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Description
Test your knowledge on the various aspects of malaria diagnosis and prevention. This quiz covers serodiagnosis, Rapid Diagnostic Tests (RDT), and effective strategies to protect against malaria in endemic areas. Challenge yourself with questions on clinical manifestations and WHO recommendations.