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Total Categories: 6
Influenza is exclusively caused by bacteria, necessitating antibiotic treatment.
Answer: False
Influenza is caused by influenza viruses, not bacteria. Antibiotics are ineffective against viral infections.
Influenza B viruses are characterized by subtypes like H1N1 and H3N2, similar to Influenza A.
Answer: False
Influenza B viruses do not possess subtypes such as H1N1 or H3N2; these are characteristic of Influenza A. Influenza B is distinguished by its two distinct lineages, B/Victoria and B/Yamagata.
Influenza D virus is a major cause of seasonal epidemics in humans.
Answer: False
Influenza D virus is primarily found in cattle and is not known to cause illness in humans, therefore it is not a cause of seasonal epidemics in people.
Influenza A and B viruses possess eight genome segments, while Influenza C and D viruses have seven.
Answer: True
Influenza A and B viruses possess eight genome segments encoding 10 major proteins, whereas Influenza C and D viruses have seven genome segments encoding nine major proteins.
Influenza A virus subtypes are identified based on combinations of the M2 and NP proteins.
Answer: False
Influenza A virus subtypes are identified based on combinations of the hemagglutinin (H) and neuraminidase (N) surface proteins, not M2 or NP proteins.
Influenza B virus has two distinct lineages, B/Victoria and B/Yamagata, which both circulate in humans.
Answer: True
Influenza B virus is characterized by two distinct lineages, B/Victoria and B/Yamagata, both of which continue to circulate in human populations and contribute to seasonal epidemics.
Influenza A and B viruses possess eight genome segments, while Influenza C and D viruses have seven.
Answer: True
Influenza A and B viruses possess eight genome segments encoding 10 major proteins, whereas Influenza C and D viruses have seven genome segments encoding nine major proteins.
Influenza A virus subtypes are identified by combinations of hemagglutinin (H) and neuraminidase (N) proteins.
Answer: True
Influenza A virus subtypes are classified based on distinct combinations of the hemagglutinin (H) and neuraminidase (N) surface glycoproteins.
What is influenza commonly known as, and what causes it?
Answer: The flu, caused by influenza viruses.
Influenza is commonly referred to as the flu and is caused by specific influenza viruses.
Which influenza virus types are primarily responsible for seasonal epidemics in humans?
Answer: Influenza A and B
Influenza A and B viruses are the primary types responsible for causing seasonal epidemics of influenza in human populations.
How are different subtypes of Influenza A virus distinguished?
Answer: By combinations of hemagglutinin (H) and neuraminidase (N) proteins.
Influenza A virus subtypes are classified based on distinct combinations of the hemagglutinin (H) and neuraminidase (N) surface glycoproteins.
Which two Influenza A subtypes are currently known to circulate among humans?
Answer: H1N1 and H3N2
The Influenza A virus subtypes currently circulating in humans are H1N1 and H3N2.
What distinguishes Influenza B virus from Influenza A?
Answer: Influenza B lacks subtypes but has two distinct lineages.
Unlike Influenza A, Influenza B virus does not possess subtypes but is characterized by two distinct lineages (B/Victoria and B/Yamagata) that circulate in humans.
What is the typical clinical presentation of Influenza C virus infection?
Answer: Mild, cold-like symptoms, mainly in children
Influenza C virus typically causes mild, cold-like symptoms, predominantly in children, and is not associated with severe epidemics.
What is the significance of the B/Yamagata lineage potentially becoming extinct?
Answer: It reduces the genetic diversity of circulating Influenza B viruses.
The potential extinction of the B/Yamagata lineage reduces the genetic diversity of circulating Influenza B viruses, which could impact future epidemiological patterns and vaccine composition.
The hemagglutinin (HA) protein's primary role is to facilitate the release of new virus particles from infected host cells.
Answer: False
The neuraminidase (NA) protein, not hemagglutinin (HA), is responsible for facilitating the release of new virus particles. HA's primary function is mediating attachment to host cells.
The HEF protein in Influenza C and D viruses performs the functions of both HA and NA proteins found in Influenza A and B.
Answer: True
The hemagglutinin-esterase-fusion (HEF) protein in Influenza C and D viruses integrates the functions of both hemagglutinin (HA) and neuraminidase (NA) proteins, mediating viral attachment and release.
The M2 protein forms ion channels essential for acidifying the virion interior during cell entry.
Answer: True
The M2 protein functions as a proton channel, facilitating the acidification of the virion interior after endocytosis, which is crucial for the release of viral ribonucleoproteins into the host cell cytoplasm.
Influenza viruses primarily replicate their genetic material in the host cell's nucleus.
Answer: True
Influenza viruses replicate their RNA genome and transcribe viral mRNA within the nucleus of the host cell, utilizing host cell machinery for these processes.
The neuraminidase (NA) protein is responsible for binding the virus to sialic acid receptors on host cells.
Answer: False
The hemagglutinin (HA) protein is responsible for binding the virus to sialic acid receptors on host cells. Neuraminidase (NA) facilitates viral release.
Which protein is essential for influenza virus attachment to host cells?
Answer: Hemagglutinin (HA)
The hemagglutinin (HA) protein is essential for mediating the attachment of the influenza virus to sialic acid receptors on the surface of host cells.
The process where the influenza virus steals 5' caps from host mRNA is called:
Answer: Cap snatching
'Cap snatching' is the mechanism by which the influenza virus's RNA polymerase cleaves the 5' caps from host mRNA to prime viral mRNA synthesis.
What is the function of the neuraminidase (NA) protein?
Answer: To facilitate the release of new virus particles from infected cells.
The neuraminidase (NA) protein's primary function is to facilitate the release of newly formed influenza virus particles from infected host cells, enabling further spread.
What is the primary function of the M2 protein in the influenza virus life cycle?
Answer: Forming proton channels to aid virion uncoating
The M2 protein functions as a proton channel, essential for acidifying the virion interior post-entry and facilitating the uncoating process, which releases viral ribonucleoproteins into the cytoplasm.
Antigenic shift involves gradual accumulation of small mutations in viral antigens, leading to seasonal epidemics.
Answer: False
Antigenic shift involves major, abrupt changes in viral antigens, often due to genetic reassortment, and can lead to pandemics. The gradual accumulation of small mutations is termed antigenic drift.
Pigs are considered 'mixing vessels' for influenza viruses because they can be infected by multiple strains, allowing genetic reassortment.
Answer: True
Pigs possess receptors for both avian and mammalian influenza viruses, enabling them to be infected by multiple strains simultaneously. This facilitates genetic reassortment, potentially creating novel viruses with pandemic potential.
Influenza viruses are transmitted solely through direct contact with contaminated surfaces.
Answer: False
Influenza viruses are primarily transmitted via respiratory droplets and aerosols. Transmission can also occur indirectly through contact with contaminated surfaces, but this is not the sole mode of transmission.
Richard Shope's 1931 research identified influenza as a bacterial infection, delaying viral research.
Answer: False
Richard Shope's 1931 research identified a virus as the cause of swine influenza, which stimulated further research into influenza viruses, rather than delaying viral research.
The 'original antigenic sin' phenomenon describes how the first flu strain encountered influences responses to later strains.
Answer: True
'Original antigenic sin,' or antigenic primacy, describes how an individual's initial immune response to an influenza strain shapes their subsequent immune responses to antigenically related or distinct strains encountered later in life.
The segmented genome of influenza viruses hinders their ability to evolve rapidly.
Answer: False
The segmented genome of influenza viruses actually facilitates rapid evolution by allowing genetic reassortment between different strains, leading to antigenic shift.
The primary natural reservoir for Influenza D virus is humans.
Answer: False
The primary natural reservoir for Influenza D virus is cattle, although it has also been detected in pigs. It is not known to cause illness in humans.
What is the natural reservoir for Influenza A virus (IAV)?
Answer: Aquatic birds
Aquatic birds serve as the primary natural reservoir for Influenza A viruses, playing a critical role in their global circulation.
What is antigenic drift?
Answer: Accumulation of small, gradual mutations in viral antigens, leading to new strains.
Antigenic drift refers to the gradual accumulation of point mutations in the genes encoding viral surface antigens, primarily HA, leading to new strains that can evade existing immunity.
Antigenic shift is particularly significant for Influenza A because:
Answer: It can result in pandemics due to a lack of pre-existing population immunity.
Antigenic shift in Influenza A can result in novel viruses to which the human population has little or no pre-existing immunity, creating conditions for widespread pandemics.
What role do pigs play in the evolution of influenza viruses?
Answer: They act as 'mixing vessels' where different strains can reassort.
Pigs serve as 'mixing vessels' for influenza viruses because their susceptibility to multiple strains allows for genetic reassortment, potentially generating novel viruses with pandemic potential.
How does the binding preference of avian influenza viruses (alpha-2,3 linkage) differ from mammalian strains (alpha-2,6 linkage) in terms of pathogenicity?
Answer: Avian viruses bind lower in the respiratory tract (lungs), potentially causing more severe disease.
Avian influenza viruses, preferring alpha-2,3 sialic acid linkages found in the lower respiratory tract, can potentially cause more severe disease in humans compared to mammalian strains that bind alpha-2,6 linkages in the upper respiratory tract.
What was the major impact of Richard Shope's 1931 research on influenza?
Answer: It identified a virus causing swine flu, stimulating further research on human influenza.
Richard Shope's identification of a virus causing swine influenza in 1931 was pivotal, stimulating significant advancements in the study of influenza virology and immunology.
Which of the following is a characteristic of Highly Pathogenic Avian Influenza (HPAI)?
Answer: Defined by causing severe disease and high mortality in chickens.
Highly pathogenic avian influenza (HPAI) is characterized by its capacity to induce severe disease and high mortality rates in poultry, particularly chickens.
How does the segmented genome of influenza viruses contribute to their evolution?
Answer: It allows for genetic reassortment between different strains infecting the same cell.
The segmented genome enables genetic reassortment when two different influenza strains coinfect a host cell, a process that significantly contributes to the rapid evolution of the virus and the emergence of novel strains.
Common symptoms of influenza include fever, muscle pain, headache, coughing, and fatigue, typically appearing within a few hours of infection.
Answer: False
The onset of influenza symptoms is typically one to four days after exposure, not within a few hours. While the listed symptoms are characteristic, the timing is inaccurate.
The 1918 Spanish flu pandemic primarily caused high mortality rates among the elderly and very young.
Answer: False
The 1918 Spanish flu pandemic was characterized by a high mortality rate among young adults, a demographic typically less affected by seasonal influenza, which disproportionately impacts the very young and elderly.
Cytokine storms, an overreaction of the immune system, can contribute to severe influenza, particularly pneumonia.
Answer: True
Cytokine storms represent a hyper-inflammatory immune response that can lead to severe influenza complications, including pneumonia and acute respiratory distress syndrome (ARDS), by causing excessive damage to lung tissue.
Influenza symptoms are typically milder and have a slower onset compared to the common cold.
Answer: False
Influenza symptoms are generally more severe and have a more sudden onset than those of the common cold, which typically presents with milder symptoms and a gradual onset.
The H5N1 subtype of avian influenza has a low case fatality rate in humans.
Answer: False
The H5N1 subtype of avian influenza is known for its high pathogenicity in avian hosts and has demonstrated a high case fatality rate in the sporadic human infections observed to date.
Influenza seasonality is consistent worldwide, with peaks always occurring in winter.
Answer: False
Influenza seasonality varies globally; while temperate regions typically experience winter peaks, tropical and subtropical regions may have year-round circulation or different seasonal patterns influenced by local climate.
Which of the following is NOT typically listed as a common symptom of influenza?
Answer: Runny nose
While a runny nose can occur with influenza, it is more characteristically associated with the common cold, which often presents with a more gradual onset and prominent nasal symptoms, unlike the sudden onset of fever and muscle aches typical of influenza.
How long does it typically take for influenza symptoms to appear after exposure?
Answer: One to four days
The incubation period for influenza, the time between exposure and symptom onset, is typically one to four days.
Which of the following is a severe complication that can arise from influenza infection?
Answer: Pneumonia
Pneumonia is a significant and potentially severe complication that can arise directly from influenza virus infection or secondary bacterial infection.
Which group is NOT typically considered high-risk for severe influenza complications?
Answer: Healthy young adults
While anyone can develop severe influenza, healthy young adults are generally not considered a high-risk group for severe complications compared to the elderly, infants, pregnant women, or individuals with chronic health conditions.
Annual influenza vaccination is recommended as the primary method for preventing the flu.
Answer: True
Annual influenza vaccination is widely recommended as the principal strategy for preventing influenza infection and reducing its severity and complications.
The Global Influenza Surveillance and Response System (GISRS) focuses solely on developing new antiviral drugs.
Answer: False
The GISRS monitors global influenza strains to inform vaccine composition and track viral evolution. Its primary role is not the development of antiviral drugs.
Influenza viruses primarily use M2 inhibitors for treatment, as resistance to neuraminidase inhibitors is widespread.
Answer: False
Neuraminidase (NA) inhibitors are a primary class of antiviral drugs for influenza treatment. Resistance to M2 inhibitors is widespread, making them less commonly used for treatment.
Which of the following is a key non-pharmaceutical intervention for controlling influenza transmission?
Answer: Frequent hand washing and covering coughs/sneezes
Practices such as frequent hand washing and covering coughs/sneezes are crucial non-pharmaceutical interventions for reducing influenza transmission.
What is the main challenge in developing a universal influenza vaccine?
Answer: The rapid evolution of viruses (antigenic drift and shift).
The primary challenge in developing a universal influenza vaccine lies in the virus's rapid evolution through antigenic drift and shift, which constantly alters its surface antigens and necessitates frequent updates to seasonal vaccines.
The Global Influenza Surveillance and Response System (GISRS) is primarily responsible for:
Answer: Monitoring global influenza strains to inform vaccine composition.
The GISRS monitors global influenza virus strains to track antigenic changes and inform the composition of seasonal influenza vaccines, ensuring optimal protection.
RT-PCR is a laboratory method for diagnosing influenza that is known for its speed and accuracy.
Answer: True
Reverse transcription polymerase chain reaction (RT-PCR) is a highly sensitive and specific nucleic acid-based diagnostic test for influenza, valued for its speed and accuracy.
Which laboratory test is often considered the gold standard for influenza diagnosis due to its speed and accuracy?
Answer: Nucleic acid-based tests like RT-PCR
Nucleic acid-based tests, particularly RT-PCR, are frequently considered the gold standard for influenza diagnosis due to their high sensitivity, specificity, speed, and accuracy.