Untitled Quiz

Study Notes

Seasonal influenza is an acute respiratory tract infection caused by influenza viruses (types A, B, C, and D).
Key symptoms include sudden onset of chills, malaise, fever, muscle pains, and cough. Influenza A and B cause seasonal epidemics.
Influenza viruses are further categorized into subtypes based on protein combinations on their surfaces
Currently circulating influenza types in humans are A(H1N1) and A(H3N2). A(H1N1)pdm09 caused the 2009 pandemic.
Only type A influenza viruses have caused pandemics.
Influenza B viruses have lineages, not subtypes: B/Yamagata and B/Victoria lineages.
Influenza C is less frequent, causing mild infections and not a significant public health concern.
Influenza D primarily affects cattle and doesn't typically infect people.

Droplet nuclei, tiny particles of dried droplets (1-10 microns), spread airborne infections.
Transmission occurs through particles, dust, or droplet nuclei suspended in the air.
Influenza spreads directly from person to person via droplets from sneezes or coughs.
The virus enters the body through the respiratory tract.

Ventilation: Essential to control the spread. Use monitored negative airflow ventilation (at least 6 air changes per hour) with exhaust filtration. Routine work areas need adequate ventilation with at least 2 windows per room (10% of floor space, cross-ventilation).
Avoid overcrowding: Maintain at least 2 meters spacing between bed centers in facilities.
Respiratory protection: Healthcare staff and patients should wear surgical masks. N95 respirators are often recommended for healthcare settings.
Hand hygiene: Wash hands (at least 20 seconds) using soap and water, or alcohol-based hand sanitizer (60% alcohol).
Avoid touching your face: Keeps germs away from eyes, nose, and mouth.
Cover coughs and sneezes: Use tissues or elbows to cover coughs and sneezes; wash hands afterwards.
Clean surfaces: Regularly clean frequently touched surfaces.
Avoid sick people: Avoid contact with sick people. If sick, stay home for 24 hours after fever subsides.

Crowds, especially during peak flu season, increase infection risk in
- Child care centers
- Schools
- Office buildings
- Public transportation.

Vaccination is the most effective way to prevent influenza.
Annual vaccination is recommended due to waning immunity.
Vaccines are updated to match circulating viruses.
Inactivated (IIV), live-attenuated (LAIV), and recombinant (RIV) influenza vaccines are available. (IIV and RIV are injectable, LAIV is nasal spray.)
Vaccination is crucial for high-risk groups, including pregnant women, children (6 months to 5 years), people over 65, people with chronic medical conditions, and healthcare workers.

Symptoms typically appear 1-4 days (average 2 days) after infection.
Symptoms include sudden fever, dry cough, headache, muscle/joint pain, and generally feeling unwell ("malaise")
Cough may last for 2 weeks or longer.

Laboratory confirmation (for severe cases or complications).
Methods include direct antigen detection, virus isolation, and detecting influenza RNA using reverse transcriptase-polymerase chain reaction (RT-PCR).

Most individuals recover without specific treatment.
Seek medical attention for severe symptoms, those with other health conditions or high risk patients.
Treatment options include antivirals for high-risk/severe cases, as needed.
Mild cases: Rest, fluids, fever reducers.

All age groups are susceptible, but some groups (pregnant women, young children, older adults, those with chronic health conditions, those with weakened immune systems) are at higher risk for severe illness or complications.
Healthcare workers run higher risk of infection, transmission to others and exposure.
Influenza epidemics can affect productivity with worker/school absenteeism.
Hospitalization and death are associated with influenza infection, especially in high-risk groups.