L.10 Malaria Flashcards
1
Q
What is malaria?
A
A serious, sometimes fatal, vector-borne infectious disease
Malaria is primarily caused by a protozoan parasite of the genus Plasmodium.
2
Q
What causes malaria?
A
A protozoan parasite of the genus Plasmodium
3
Q
How is malaria primarily transmitted?
A
Through the bite of an infected female Anopheles mosquito
4
Q
What are less common transmission methods for malaria?
A
Blood transfusions and contaminated needles
5
Q
Where is malaria primarily found geographically?
A
Tropical and subtropical regions
6
Q
List some regions where malaria is endemic.
A
- Africa
- India
- Southeast Asia
- Middle East
- Central and South America
- Eastern Europe
- South Pacific
7
Q
Which country accounts for approximately 26% of global malaria cases?
A
Nigeria
8
Q
Which country accounts for approximately 13% of global malaria cases?
A
Democratic Republic of Congo
9
Q
What was the estimated number of malaria cases in 2023?
A
263 million cases across 83 endemic countries
10
Q
How many deaths were estimated due to malaria in 2023?
A
Approximately 1 million deaths
11
Q
What percentage of malaria deaths occurred in children under 5 in 2023?
A
~80%
12
Q
What is the most severe form of malaria?
A
P. falciparum
13
Q
What percentage of malaria cases and deaths is P. falciparum responsible for?
A
~80% of cases and ~90% of deaths
14
Q
What geographic areas are primarily affected by P. falciparum?
A
Africa and South America
15
Q
What is a unique feature of P. vivax?
A
Can relapse due to hypnozoites in the liver
16
Q
Which geographic areas are primarily affected by P. vivax?
A
Asia and Latin America
17
Q
True or False: P. ovale is common and has a significant impact on global malaria cases.
A
False
18
Q
What is a unique characteristic of P. malariae?
A
Can cause chronic infections
19
Q
Where is P. malariae primarily found?
A
West Africa
20
Q
What is a unique feature of P. knowlesi?
A
Zoonotic transmission (monkey to human)
21
Q
Where is P. knowlesi primarily found?
A
Southeast Asia
22
Q
Fill in the blank: The highest burden of malaria cases is found in _______.
A
Nigeria
23
Q
What genetic condition is associated with natural protection against malaria due to the sickling of cells?
A
Sickle Cell Trait (Hb S)
AS (heterozygous) cells sickle more readily when infected, making it easier for the spleen to remove them.
24
Q
How do Hemoglobin C (Hb C) red blood cells (RBCs) provide resistance against malaria?
A
CC RBCs resist parasite growth due to membrane properties
AC RBCs are still susceptible.
25
What is the effect of Sickle Cell Disease (SC) on malaria parasites?
Creates a poor environment for parasite survival.
26
What role do Thalassemia and G6PD Deficiency play in malaria protection?
Increased oxidative stress damages infected RBCs, reducing parasite growth.
27
What is the significance of Duffy Antigen Negativity in malaria?
Prevents P. vivax from invading RBCs.
28
What are the initial nonspecific symptoms of malaria?
Fever, chills, headache, muscle aches.
29
What severe symptoms are particularly associated with P. falciparum malaria?
Extreme fatigue, impaired consciousness, multiple convulsions, breathing difficulties, jaundice, hemoglobinuria, renal and liver failure, disseminated intravascular coagulation (DIC), shock.
30
How long does it typically take for malaria symptoms to onset after a mosquito bite?
10–15 days.
31
What complications can malaria cause during pregnancy?
Premature delivery and low birth weight.
32
What are the three stages of a classical malarial attack?
Cold Stage, Hot Stage, Sweating Stage.
33
What occurs during the Cold Stage of a malarial attack?
Chills, shivering, sensation of cold.
34
What characterizes the Hot Stage of a malarial attack?
High fever (up to 40°C/104°F), headache, vomiting, seizures (in children).
35
What happens during the Sweating Stage of a malarial attack?
Profuse sweating as fever subsides, extreme fatigue.
36
What causes the symptoms during a malarial attack?
Coincides with the rupture of schizonts in RBCs and the release of Tumor Necrosis Factor (TNF) and other cytokines.
37
What is the cause of Severe Malaria?
Caused by P. falciparum
## Footnote
P. falciparum is a protozoan parasite responsible for the most severe form of malaria.
38
What is cytoadherence in the context of Severe Malaria?
Infected RBCs stick to endothelium in cerebral vessels
## Footnote
This process is crucial for the pathophysiology of cerebral malaria.
39
What is sequestration in Severe Malaria?
Blockage of microcirculation
## Footnote
Sequestration contributes to the complications seen in cerebral malaria.
40
List the consequences of Severe Malaria.
* Endothelial injury
* Blood-brain barrier dysfunction
* Brain swelling
* Intracranial hypertension
* Coma and death if untreated
## Footnote
These consequences can lead to severe neurological damage and death.
41
What is the first step in the malaria life cycle?
Infected female anopheles mosquito injects sporozoites into human blood
## Footnote
This initiates the infection process in humans.
42
Where do sporozoites migrate after entering human blood?
Sporozoites migrate to the liver and invade hepatocytes
## Footnote
This is crucial for the development of the parasite.
43
What is the duration sporozoites remain in the liver?
7-28 days
## Footnote
During this period, sporozoites undergo cell division.
44
What do liver schizonts release into the bloodstream?
Merozoites
## Footnote
Merozoites are the next stage in the malaria life cycle that infect red blood cells.
45
How do merozoites invade red blood cells?
By attaching to red cell membrane receptors + are endocytosed
## Footnote
This is the mechanism through which malaria parasites enter red blood cells.
46
What does the merozoite develop into within a red blood cell?
Trophozoite
## Footnote
The trophozoite is the feeding stage of the parasite.
47
What does the trophozoite feed on?
Hb (hemoglobin)
## Footnote
Trophozoites utilize hemoglobin for protein synthesis.
48
What is released as a byproduct of hemoglobin digestion by trophozoites?
Haemozoin pigment
## Footnote
Haemozoin is a waste product of the digestion process.
49
How long does it take for trophozoites to divide and produce schizonts?
2-3 days
## Footnote
This division is critical for the propagation of the malaria parasite.
50
What happens when schizonts rupture?
They release merozoites
## Footnote
This continues the cycle of infection in red blood cells.
51
What develops from some trophozoites that will infect a biting mosquito?
Gametocytes
## Footnote
Gametocytes are essential for the continuation of the malaria life cycle in mosquitoes.
52
Where do gametocytes undergo their sexual cycle?
In the stomach of anopheline mosquito
## Footnote
This is where male and female gametocytes combine to form sporozoites.
53
What shape do gametocytes take depending on their species?
Banana/crescent shape
## Footnote
The shape can help in identifying the species of the malaria parasite.
54
What is the trophozoite stage often referred to as?
Ring stage
## Footnote
This is the most commonly observed stage of the malaria parasite.
55
What is the schizont stage characterized by?
Parasite starts to divide (schizogony) in the liver and PB
## Footnote
This stage is crucial for the multiplication of the malaria parasite.
56
What color are male gametocytes compared to female gametocytes?
Males are more pink in colour than females
## Footnote
This color difference can be useful for identification under a microscope.
57
What is the anticoagulant used for blood samples in malaria testing?
EDTA blood sample
## Footnote
EDTA is commonly used to prevent blood clotting in laboratory tests.
58
What is the recommended sample age for best results in malaria testing?
< 2 hours old
## Footnote
Fresh samples provide more accurate test results.
59
What clinical information must be provided for malaria testing?
Travel history and presenting symptoms
## Footnote
This information helps in assessing the likelihood of malaria infection.
60
What is the purpose of a Full Blood Count (FBC) in malaria testing?
Look for anaemia, thrombocytopenia, WBC changes
## Footnote
FBC helps in identifying blood-related complications of malaria.
61
What does a Rapid Diagnostic Test (RDT) do?
Quick screening using malaria-specific antigens
## Footnote
RDTs provide a fast initial assessment for malaria infection.
62
What is the role of Blood Film Microscopy in malaria diagnosis?
Confirm infection, identify species, stage parasites, estimate parasitaemia
## Footnote
Microscopy is a traditional method for detailed analysis of malaria infections.
63
What does PCR (Nested / Real-time) detect in malaria testing?
Highly sensitive and specific detection of Plasmodium DNA
## Footnote
PCR is a molecular technique that enhances the accuracy of malaria diagnosis.
64
What is Loop-mediated Isothermal DNA Amplification (LAMP) used for?
Rapid, sensitive nucleic acid detection method for malaria DNA
## Footnote
LAMP is an innovative technique that simplifies the detection process.
65
What type of anaemia is commonly found in malaria patients?
Normochromic, normocytic anaemia
## Footnote
This type of anaemia indicates a normal size and color of red blood cells.
66
How much can hemoglobin decrease per day in malaria cases?
2g/dL (20g/L) per day
## Footnote
Rapid decreases in hemoglobin can indicate severe disease.
67
What are possible findings in white blood cell counts during malaria?
* Monocytosis
* Eosinopenia (early stages)
* Reactive eosinophilia (during recovery)
* Activated neutrophils
## Footnote
WBC changes provide insight into the immune response to malaria.
68
What is a common finding regarding platelets in malaria?
Thrombocytopenia is very common
## Footnote
Low platelet counts are a significant indicator of malaria severity.
69
What can an unexplained thrombocytopenia indicate?
Consider malaria
## Footnote
Further investigation is needed when low platelet counts are observed.
70
What coagulation changes are often seen in malaria?
* Prolonged PT and APTT
* Elevated fibrinogen
## Footnote
These changes reflect the activation of the coagulation cascade.
71
What laboratory features may be mildly raised in malaria cases?
* Liver Function Tests (LFTs)
* LDH
* Bilirubin
* C-Reactive Protein (CRP)
* Procalcitonin
## Footnote
Elevated levels of these markers can indicate organ involvement and inflammation.
72
What microscopy method is considered the gold standard for malaria diagnosis?
Thick Film and Thin Film
## Footnote
Thick Film detects low parasitaemia with high sensitivity, while Thin Film identifies species and parasite stage.
73
What is the sensitivity advantage of Thick Film over Thin Film?
10x sensitivity
## Footnote
Thick Film examines a larger volume of blood and is more effective in detecting low levels of parasites.
74
What staining method is used for Thick Film microscopy?
Fields stain (rapid)
## Footnote
Thin Film microscopy uses Giemsa stain at pH 7.2 and freshly prepared.
75
What key feature is assessed in Thin Film microscopy for species identification?
Size and shape of infected RBCs
## Footnote
Other features include presence of inclusions, amount of RBC cytoplasm occupied by the parasite, appearance of trophozoites and schizonts, and gametocyte morphology.
76
What is the appearance of P. falciparum-infected RBCs?
RBC not enlarged and parasite is neat
## Footnote
P. falciparum can infect more than one RBC.
77
What is the appearance of P. vivax-infected RBCs?
RBC is enlarged and parasite fills cells
## Footnote
This indicates a different morphology compared to P. falciparum.
78
What do Rapid Diagnostic Tests (RDTs) detect?
Antigens using specific antibodies
## Footnote
Examples include HRP-2 for P. falciparum and pLDH for all Plasmodium species.
79
What is a limitation of RDTs in malaria diagnosis?
False positives and lower sensitivity than expert microscopy
## Footnote
RDTs cannot quantify parasitaemia or reliably detect mixed-species infections.
80
Fill in the blank: The __________ is a pan-Plasmodium marker used in RDTs.
Plasmodium aldolase
81
What should be done regarding parasite quantification during malaria diagnosis?
Should be repeated daily until no parasites (except gametocytes) are seen
## Footnote
This ensures thorough monitoring of the infection status.
82
What is the GOLD STANDARD for laboratory diagnosis of malaria?
Microscopy
## Footnote
Microscopy is the most reliable method for diagnosing malaria.
83
What stain is used for thick film in malaria diagnosis?
Fields Stain
## Footnote
Thick films are used for detection and estimation of parasitaemia.
84
What stain is used for thin film in malaria diagnosis?
Giemsa stain (pH 7.2)
## Footnote
Thin films are used for species identification and parasite staging.
85
How many trained scientists must examine slides for malaria diagnosis?
At least two
## Footnote
This is to ensure accuracy in the diagnosis.
86
What must be reported if P. falciparum or P. knowlesi is detected?
Parasitamia (%)
## Footnote
Mandatory reporting ensures proper monitoring of malaria cases.
87
What are RDTs used for in malaria diagnosis?
Preliminary diagnosis and supplementary tool
## Footnote
RDTs provide quick initial results but are not definitive.
88
What should trigger a malaria investigation according to lab alerts?
Unexplained thrombocytopenia or suspicious scatter plot abnormalities
## Footnote
These findings may indicate the presence of malaria.
89
What enhances the accuracy of malaria diagnosis, especially when microscopy is inconclusive?
Molecular techniques
## Footnote
Molecular methods are crucial for distinguishing between similar species.
90
What are the main molecular methods for malaria diagnosis?
* Nested PCR (Polymerase Chain Reaction)
* Multiplex Real-Time PCR
* Loop-Mediated Isothermal Amplification (LAMP)
## Footnote
These methods provide higher specificity and sensitivity.
91
What is one advantage of molecular methods over morphology in malaria diagnosis?
Accurate differentiation between morphologically similar species
## Footnote
For example, distinguishing P. knowlesi from P. malariae.
92
What can molecular methods detect that microscopy may miss?
Mixed infections
## Footnote
Molecular tests can identify multiple Plasmodium species in a sample.
93
What discrepancy can molecular testing resolve?
Discrepancies between rapid diagnostic tests (RDTs) and microscopy findings
## Footnote
For instance, blood film positive for P. falciparum but negative RDT results.
94
In what situations is molecular testing particularly useful?
* Negative blood smears with strong clinical suspicion of malaria
* Suspected low-level parasitemia
## Footnote
These cases may not be detected by standard microscopy.
95
What is a limitation of molecular methods in malaria diagnosis?
Cannot provide parasitemia counts
## Footnote
Molecular methods cannot quantify the percentage of infected red cells.
96
What may a positive PCR result indicate?
* An active infection
* Residual DNA from a recently treated infection
## Footnote
This ambiguity is a limitation for treatment monitoring.
97
Is PCR used for treatment monitoring in malaria?
No
## Footnote
Due to the possibility of residual DNA from past infections.
98
What is Nested PCR?
A two-step modification of standard PCR
## Footnote
First round uses genus-specific primers to amplify any Plasmodium DNA; second round uses species-specific primers to amplify DNA of individual Plasmodium species.
99
What is the advantage of Nested PCR?
Increased sensitivity and reduced non-specific amplification
100
What does LAMP stand for?
Loop-Mediated Isothermal Amplification
101
What are the key characteristics of LAMP?
Rapid, highly sensitive, and cost-effective method targeting Plasmodium mitochondrial DNA
102
What does Eiken Loopamp MALARIA detect?
P. falciparum (Pf-LAMP) and Plasmodium genus DNA (Pan-LAMP)
103
What does Meridian Illumigene MALARIA detect?
Plasmodium genus DNA only
104
What is the detection threshold for LAMP?
1–5 parasites per microliter
105
What is the speed of results for LAMP?
Results within 1 hour
106
What types of samples can LAMP work on?
* Fresh blood samples
* Frozen blood samples
* Dried blood spots on filter paper
107
What must be monitored in parasitemia monitoring?
% Parasitemia for P. falciparum and P. knowlesi infections
108
Why is parasitemia monitoring critical?
For assessing disease severity and response to treatment
109
What is the protocol for blood film examination if initial smears are negative?
Repeat blood smears after 12–24 hours, then again after another 24 hours (total of three smears recommended)
110
What can cause false negatives in blood smears?
* Very low parasitemia
* Sampling during periods without circulating parasites
111
What does the presence of malaria pigment (hemozoin) in mononuclear white cells suggest?
Recent or ongoing infection
112
What may automated blood cell analyzers show that prompts manual review?
Abnormal white cell differential histograms
113
What is the main goal of vector control interventions?
Prevent mosquito bites and interrupt transmission
## Footnote
Vector control is essential for malaria prevention.
114
What are the two main methods of vector control?
* Insecticide-treated nets (ITNs)
* Indoor residual spraying (IRS)
## Footnote
These methods aim to protect individuals from mosquito bites and reduce transmission.
115
What is the function of insecticide-treated nets (ITNs)?
Kill or repel mosquitoes; essential in sleeping areas
## Footnote
Addressing pyrethroid resistance is a major focus for ITNs.
116
What is the purpose of indoor residual spraying (IRS)?
Application of insecticides to walls and surfaces indoors
## Footnote
IRS helps in reducing indoor mosquito populations.
117
Define chemoprevention in the context of malaria.
Treatment to prevent malaria in individuals living in endemic areas
## Footnote
It focuses on those at continuous risk of malaria.
118
What is chemoprophylaxis?
Given to travelers entering malaria-endemic regions
## Footnote
It helps protect individuals who are temporarily at risk.
119
Name three common drugs used for malaria chemoprophylaxis.
* Atovaquone-proguanil
* Mefloquine
* Doxycycline
## Footnote
These drugs are effective in preventing malaria infection.
120
What is a significant emerging biological threat to malaria control related to gene deletions?
Deletions in the pfhrp2 and pfhrp3 genes can cause false-negative RDT results
## Footnote
This issue was first reported in Peru in 2010.
121
What is the concern regarding antimalarial drug resistance?
Artemisinin partial resistance has emerged in Southeast Asia and Africa
## Footnote
Resistance to ACT partner drugs is also a major concern.
122
What is the status of insecticide resistance in malaria control?
Resistance to pyrethroids is widespread; documented in 55 out of 64 countries monitored from 2018 to 2023
## Footnote
This resistance poses challenges for vector control efforts.
123
Which invasive mosquito species has spread to African cities?
Anopheles stephensi
## Footnote
Its spread increases the risk of malaria resurgence in previously controlled areas.
124
How does climate change affect malaria transmission?
Altered rainfall patterns, temperature increases, and expanded mosquito breeding zones increase malaria transmission risks
## Footnote
Climate change is a significant factor influencing vector ecology.
125
What is the first approved malaria vaccine?
RTS,S/AS01 (Mosquirix)
## Footnote
Approved in 2015.
126
What are the components of RTS,S/AS01 (Mosquirix)?
* Genes from P. falciparum circumsporozoite protein
* A hepatitis B surface antigen
* Combined with a chemical adjuvant to enhance immune response
127
What is the vaccination schedule for RTS,S/AS01 (Mosquirix)?
Four doses, starting at 5 months of age.
128
What was the WHO recommendation for RTS,S/AS01 in 2021?
Widespread use among children in sub-Saharan Africa and other regions with high P. falciparum burden.
129
What is the target population for the R21/Matrix-M vaccine?
Children at risk of malaria in endemic regions.
130
When was the R21/Matrix-M vaccine approved?
October 2023.
131
What is a key feature of the R21/Matrix-M vaccine?
Developed as a next-generation vaccine with potentially higher efficacy than RTS,S.
132
What is the goal of vector control in malaria prevention?
Break the mosquito-human transmission cycle.
133
What are Insecticide-Treated Nets (ITNs) used for?
* Prevent mosquito bites during sleep
* Kill mosquitoes attempting to feed
134
What does Indoor Residual Spraying (IRS) involve?
Insecticides applied to walls where mosquitoes rest.
135
What are environmental measures in malaria prevention?
* Drainage of stagnant water
* Clearing mosquito breeding sites
136
What is chemoprevention?
Preventative antimalarial treatment for populations in endemic areas (e.g., children, pregnant women).
137
What is chemoprophylaxis?
For travelers entering endemic regions.
138
What are common drugs used for chemoprophylaxis?
* Atovaquone-proguanil
* Doxycycline
* Mefloquine
139
What is the role of health education in malaria prevention?
Awareness about malaria prevention and promotion of early diagnosis and treatment.
