Influenza Overview and Classification

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Questions and Answers

What is the primary cause of a runny nose during the phase of infection?

Stimulation of the immune response

Increased extracellular fluid escape (correct)

Lack of hydration

Constricting blood vessels

What complication can arise from the spread of the virus to the lower respiratory tract?

Bacterial pneumonia (correct)

Acute bronchitis

Chronic obstructive pulmonary disease

Viral meningitis

Which symptom is NOT typically associated with the abrupt onset of influenza?

Cough

Bloating (correct)

Chills

Fever

Which of the following tests can help diagnose influenza?

Viral culture from a throat swab Signup and view all the answers

When are antiviral medications most effective for influenza treatment?

Within 48 hours of symptom onset Signup and view all the answers

What is the action of oseltamivir (Tamiflu) in treating influenza?

Preventing viral release from infected cells Signup and view all the answers

What is a common side effect of antiviral medications for influenza?

Gastrointestinal symptoms Signup and view all the answers

Which of the following is a supportive care measure for managing influenza symptoms?

Utilizing antipyretics for fever management Signup and view all the answers

Which types of influenza viruses are known to cause significant illness in humans?

Influenza A and B Signup and view all the answers

How are influenza A viruses categorized?

By the presence of hemagglutinin (H) and neuraminidase (N) proteins Signup and view all the answers

What is the primary cause of influenza transmission?

Inhalation of aerosolized viral particles Signup and view all the answers

What typically characterizes an epidemic of influenza?

Yearly occurrences of previously circulating strains Signup and view all the answers

Which influenza type is known to cause milder illness and is not associated with pandemics?

Influenza C Signup and view all the answers

What happens when a new strain of influenza A virus reaches humans?

There is a lack of immunity, allowing for quick spread Signup and view all the answers

How long is the typical incubation period for the influenza virus?

1-7 days Signup and view all the answers

Which cells does the influenza virus primarily target in the respiratory tract?

Mucous-secreting and ciliated cells Signup and view all the answers

Study Notes

Influenza Overview

Influenza (Flu) is a leading cause of upper respiratory tract infections in humans.
More contagious than bacterial respiratory infections.

Classification of Influenza Viruses

Four serotypes: A, B, C, and D.
Only types A and B cause significant illness in humans.

Influenza A

Subtyped based on two surface proteins: hemagglutinin (H) and neuraminidase (N).
Naming convention includes both H and N types (e.g., H3N2).
Most common and virulent flu virus, infects multiple animal species.
New mutations can lead to pandemics as humans have no immunity.
H1N1 (swine flu) emerged in 2009, resulting in a global pandemic.
Epidemics are localized outbreaks caused by variants of circulating strains.

Influenza B, C, D

Influenza B and C only infect humans and are not divided into subtypes.
B is associated with regional epidemics, less severe than A.
C causes mild illness, does not lead to epidemics or pandemics.
Influenza D affects only animals.

Incubation and Transmission

Incubation period lasts from 1 to 5 days.
Infectious starting one day before symptoms appear and for about 5-7 days after onset.
Transmission occurs through inhalation or ingestion of viral particles from droplets.

Pathophysiology

Virus attaches to and enters respiratory epithelial cells, replicating within.
This triggers inflammatory and immune responses.
Damage to mucous-secreting and ciliated cells leads to symptoms like a “runny nose.”
If the virus spreads to the lower respiratory tract, it can compromise natural defenses and lead to complications, such as bacterial pneumonia.

Clinical Manifestations

Abrupt onset of symptoms, including chills, fever, malaise, headache, cough, sore throat, and fatigue.

Diagnostic Studies

Diagnosis based on health history, physical assessment, and community outbreak awareness.
Viral culture from respiratory samples helps identify virus type and strain.

Antiviral Medications

Effective within 48 hours of symptom onset, they can shorten illness duration, reduce symptom severity, and prevent complications.
Common antivirals:
- Oseltamivir (Tamiflu): Oral; inhibits neuraminidase enzyme.
- Zanamivir (Relenza): Inhaled; similar action to oseltamivir.
- Peramivir (Rapivab): Intravenous option for severe cases.
- Baloxavir marboxil (Xofluza): Targets different stages of viral replication.
Potential side effects include gastrointestinal symptoms and neurological issues (rare).

Supportive Care

Hydration: Maintain fluid intake to prevent dehydration.
Rest: Encourages recovery and supports immune response.
Fever Management: Use of antipyretics (e.g., acetaminophen, ibuprofen).

Symptomatic Relief

Decongestants: Alleviate nasal congestion.
Cough suppressants and other supportive medications for symptom management.

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Description

This quiz covers the essential aspects of influenza, including its classification, serotypes, and the significance of Influenza A, B, C, and D. Understand the modes of transmission, illness severity, and the impact of mutations on public health. Test your knowledge on this critical respiratory infection.