Malaria Diagnosis and Prevention Quiz

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Questions and Answers

What is a limitation of serodiagnosis in diagnosing malaria?

It can accurately determine the species of malaria.

It is highly effective in acute cases.

It relies solely on the presence of malaria parasites.

Antibodies may not be present yet in acute cases. (correct)

What is the primary advantage of using Rapid Diagnostic Tests (RDT) for malaria diagnosis?

They are always interpreted in isolation.

They can assist inexperienced staff in low prevalence areas. (correct)

They completely replace the need for microscopy.

They are slower than traditional methods.

Which of the following statements correctly describes the use of PCR in malaria diagnosis?

PCR is used to confirm malaria in all patients.

PCR is indicated when parasites are not seen in blood films but symptoms are present. (correct)

PCR can determine concurrent infections only.

PCR is the first test performed for all malaria cases.

Which combination of Plasmodium species correctly matches simian and human types?

P. cynomolgi - P. vivax (B) Signup and view all the answers

Why might serodiagnosis be particularly useful from an epidemiological perspective?

It assesses population immunity towards malaria. (D) Signup and view all the answers

What is one of the principles of malaria prevention and control for travelers to endemic areas?

Prophylaxis with Doxycycline (A) Signup and view all the answers

Which of the following methods is NOT included in the malaria prevention strategies?

Inoculation with a live parasite vaccine (A) Signup and view all the answers

What is suggested as a protective measure for individuals in malarious areas?

Using insect repellant and wearing long sleeves (C) Signup and view all the answers

Which of the following is NOT part of the WHO's ABCD recommendations for malaria protection?

Use of public transportation (A) Signup and view all the answers

Which of the following best describes the use of vaccines in malaria prevention?

Vaccines are currently in development and not yet available. (A) Signup and view all the answers

What is a major clinical manifestation of blackwater fever?

Dark red or blackish urine (C) Signup and view all the answers

Which of these complications is not associated with blackwater fever?

Nephrotic syndrome (B) Signup and view all the answers

Which condition is characterized by high continuous fever and is associated with multiple organ failure?

Septicemic malaria (D) Signup and view all the answers

What causes hypoglycemia in malaria patients, particularly during pregnancy?

Glucose consumption by the parasite (C) Signup and view all the answers

What is the main complication associated with P.malariae infections?

Nephrotic syndrome (C) Signup and view all the answers

What is the primary characteristic of Nested PCR?

It involves two sequential PCR reactions. (D) Signup and view all the answers

Which PCR method is known for real-time monitoring of DNA amplification?

Real-time PCR (D) Signup and view all the answers

Which technique is used for confirming malaria diagnosis through laboratory investigations?

Thin and thick blood films (C) Signup and view all the answers

What is a major advantage of using LAMP for DNA amplification?

It operates under isothermal conditions. (C) Signup and view all the answers

What is a common feature of algid malaria?

Adrenal insufficiency-like syndrome (D) Signup and view all the answers

What causes acute renal failure in severe cases of malaria?

Tubular necrosis (B) Signup and view all the answers

Which factor significantly affects the choice of antimalarial drugs for treatment?

Geographical location and drug resistance. (B) Signup and view all the answers

What is the main purpose of treating malaria with specific antimalarial drugs?

To terminate parasitaemia and prevent transmission. (D) Signup and view all the answers

What is the primary characteristic of cerebral malaria caused by P. falciparum?

Formation of knobs on RBCs (D) Signup and view all the answers

Which of the following complications is most severe in malaria?

Cerebral malaria (A) Signup and view all the answers

What is a direct consequence of the obstruction caused by sequestrated RBCs in cerebral malaria?

Anoxia and ischemia (A) Signup and view all the answers

How do late stage schizonts of P. falciparum contribute to hemolytic anemia?

By promoting adhesion to endothelial cells (C) Signup and view all the answers

What mechanism is involved in the multi-factorial process leading to cerebral malaria?

Sequestration and inflammation (C) Signup and view all the answers

Which statement best describes the role of the adhesive proteins secreted by P. falciparum?

They promote adhesion of infected and non-infected RBCs. (A) Signup and view all the answers

What is one of the major consequences of the microvascular obstruction in cerebral malaria?

Development of hemorrhage (A) Signup and view all the answers

In which condition does P. falciparum lead to coma and potentially death?

Cerebral malaria (A) Signup and view all the answers

What is the primary advantage of using a thick blood smear for diagnosing malaria?

It helps in detecting infection due to the larger volume of blood used. (B) Signup and view all the answers

Which type of blood smear allows for the identification of the malaria parasite species?

Thin blood smear (B) Signup and view all the answers

In the case of P.vivax infection, what morphological change occurs in red blood cells?

Red blood cells become enlarged. (B) Signup and view all the answers

What is a distinguishing feature of P.falciparum gametocytes?

They appear banana or crescent-shaped. (A) Signup and view all the answers

What type of stippling is associated with P.vivax infections?

Fine dots (Schuffner's dot) (D) Signup and view all the answers

In P.malariae infections, which of the following is observed in the ring-form trophozoite?

It has one or two chromatin dots and a thicker cytoplasm ring than P.falciparum. (D) Signup and view all the answers

What is the schizont structure in P.vivax characterized by in terms of merozoite numbers?

12-24 merozoites. (D) Signup and view all the answers

What happens to red blood cells in thick blood smears during the microscopy process?

They are lysed to increase visibility of the parasites. (B) Signup and view all the answers

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 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.