Multiple choice ­questions: answers Chapter 1. Biomarkers for dengue: prospects and challenges

1. 2. 3. 4.

5.

Dengue virus infections: c. Result in severe manifestations in approximately 5% of hospitalized cases Severe dengue: d. Is characterized by bleeding tendencies, organ dysfunc­ tion and capillary leakage Potential dengue biomarkers: e. All of the above Markers of immune activation in dengue: a. Will need careful standardization of the sample collection and analysis, plus interpretation of the results will require that overall clinical context is considered Regarding potential viral biomarkers: b. Early peak viral loads has been correlated to disease severity

Chapter 2. Dengue diagnosis: commercially available kits and laboratory support

1.

An efficient diagnosis of dengue is important for: a. Clinical care, disease surveillance, pathogenesis studies and vaccine research

2.

The desirable window for diagnosing dengue infections relies on: c. The onset of the fever when the virus can be isolated and viral genome detected until the tenth day after when anti-dengue antibodies can be detected

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Multiple choice ­questions: answers

3.

In the primary dengue virus infection: a. A low-titer antibody response is observed, with IgM first produced and IgG detectable in the end of the first week of the disease at low titers

4.

In relation to the specific laboratorial diagnosis of dengue, it is correct to state that: d. Detection of IgM, IgG and nonstructural protein 1 (NS1) are the most widely used tests for dengue diagnosis

5.

NS1 is a highly conserved protein secreted from infected cells and used as a tool for dengue diagnosis, and: a. It can be found in the blood circulation for up to 9 days from illness onset

Chapter 3. Lessons learned from dengue: focus on Taiwan

1.

Which of the following concerning dengue epidemiology is not correct? b. Dengue hemorrhagic fever is an important cause of mor­ bidity in Southeast Asia and occurs almost exclusively in adults

2.

Which of the following descriptions is least appropriate for dengue hemorrhagic fever/dengue shock syndrome? d. Dengue virus serotype 4 is significantly associated with dengue shock syndrome

3.

Which of the following is not correct concerning biomarkers in dengue virus infection? a. Serum IP-10 and MIP-1 levels are decreased in the febrile phase of dengue infection

4.

Which protein can be expressed on the surface of dengue virusinfected cells? a. NS1

5.

Anti-dengue virus NS1 antibodies may bind to which of the following factors/cells? d. All of the above

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6. 7.

Which one of the clinical findings is not true in severe dengue patients? c. Patients’ vascular leakage is irreversible Which one of the following dengue proteins is an early diagnostic marker for dengue virus infection? c. NS1 protein

Chapter 4. Dengue and international travel

1.

According to WHO estimates, how many cases of dengue infection occur annually? c. 50 million

2.

Which of these countries is not considered at risk for dengue infection? b. Morocco

3.

Which of these is a competent vector for the transmission of dengue infection? a. Aedes albopictus

4.

What are the classic signs and symptoms of dengue fever? a. Fever, arthralgia, maculo–papular rash, retro-orbital pain

5.

What are the main organs involved in dengue hemorrhagic fever? b. Liver, CNS and heart What are the main risk factors for acquiring dengue among travelers? d. All of the above

6. 7.

What are, currently, the possible preventive measures that travelers may adopt to avoid dengue infection? a. Taking precautions to avoid mosquito bites, using mosquito repellents, protective clothes and insecticides

8.

Which are the travelers considered at higher risk of severe manifestations of dengue infection? b. All of the above

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Multiple choice ­questions: answers

Chapter 5. Intraepidemic increases in dengue disease severity: applying lessons

1.

The fundamental pathophysiological mechanism underlying dengue hemorrhagic fever (severe dengue) is: c. Increased vascular permeability

2.

Rapid increases in disease severity accompanying secondary dengue virus type 2 infections in Cuba and Nicaragua were found to be associated with: b. Single amino acid changes in nonstructural proteins be­ tween viruses recovered before and during outbreak of increased disease severity

3.

Dengue hemorrhagic fever occurs most frequently during: d. Secondary dengue infections

4.

Reported rapid increases in severity of dengue disease during outbreaks is probably due to: d. Changes in viral protein structures that affect disease outcome by mechanisms not yet understood

5.

In most outbreaks, dengue vascular permeability syndrome (dengue hemorrhagic fever) is caused by: d. Viruses with identical genetic structure to viruses recovered in the same outbreak from patients with dengue fever

Chapter 6. Prospects for controlling dengue spread: vaccines and vector control

1.

Which of the following is the primary vector of dengue virus (DENV)? c. Aedes aegypti

2.

Which vaccine strategy is furthest along in clinical development? d. Live attenuated virus vaccine

3.

What is the extrinsic incubation period? b. The period of time required for the virus to complete its development in the mosquito

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4.

How long does cross-protective immunity last after initial DENV infection? d. Months to years

5.

What is (are) the major factor(s) contributing to the continued spread and intensification of DENV? d. All of the above

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