Topic 7 - Influenza
The Great Influenza (Chapter 10 Notes)
Page 1: Title Page
Title: The Great Influenza
Chapter 10
Page 2: Poem
Poem about influenza:
"I lost a little birdAnd its name was Enza.I opened the windowAnd in-flu-enza!"
Page 3: Infectious Agent of Flu
Early beliefs about epidemics:
Attributed to stars alignment and poisonous vapors (miasma).
Discovery of bacteria in the late 19th century linked to flu:
Haemophilus influenzae identified by Richard Pfeiffer (Germany).
Page 4: History of Swine Flu
1918: Veterinarian in Cedar Rapids, Iowa observed swine with flu-like illness.
Family members close to infected pigs also fell ill.
1922-1923: Outbreaks of swine flu noted across the Midwest.
Veterinarians transmitted swine flu through nasal mucus.
Page 5: Identifying the Agent
Richard Shope (1930s):
Identified the infectious agent as a virus.
Filtering nasal mucus still allowed for flu transmission in pigs.
Page 6: Human Influenza Virus
Wilson Smith, Christopher Andrewes, and Patrick Laidlaw (1933, England):
Isolated the first human influenza virus.
Used filtrate from Andrewes to infect ferrets (demonstrated Koch’s postulates).
Classification as Influenza A.
Page 7: Spanish Flu Pandemic
Timeline: 1918-1920.
Death toll: 50 to 100 million worldwide.
United States deaths: 500,000 to 675,000 in 120 days.
Page 8: Impact of Media
Media and public officials exacerbated panic during the outbreak:
Misinformation and minimized effects.
Ineffectual public health measures led to loss of faith in the medical profession.
Page 9: Influenza's Role in WWII
Connection to WWI:
Influenza affected German army morale and soldier strength during war.
President Woodrow Wilson, sick from influenza, made unfavorable agreements.
Result: Economic hardships and rise of the Nazi party.
Page 10: Influenza Pandemics Overview
Table 33.2: Influenza pandemics with year, name, and strain.
1889: Russian - H2N2
1900: Old Hong Kong - H3N8
1918: Spanish - H1N1
1957: Asian - H2N2
1968: Hong Kong - H3N2
2009: Swine - H1N1 C
Page 11: H1N1 Pandemic
2009 H1N1 flu pandemic details:
First cases in Mexico and U.S. (April 2009).
WHO declared H1N1 pandemic (June 11, 2009).
National emergency declared in the U.S. (October 25, 2009).
Over 18,000 deaths reported by May 30, 2010.
Page 12: H5N1 Bird Flu
H5N1 (Bird flu):
First human infection reported in 1997 (Hong Kong).
Spread from chickens to humans and linked to infected poultry over multiple continents.
Page 13: H5N1 Breakdown
Countries impacted by H5N1 infections in birds and humans are outlined.
Page 14: Airborne Viral Diseases
Transmission: respiratory droplets.
Table 10.2: Key airborne viral diseases details:
Influenza: 1-2 days inoculation period, symptoms include fever, muscle aches, and coughing.
Suggested immunization strategies.
Page 15: Influenza Transmission
Primary route: aerosolized droplets.
Secondary route: fomites.
Incubation: 24 to 48 hours.
Factors exacerbating spread: crowding and poor hygiene practices.
Page 16: Influenza Characteristics
RNA virus (orthomyxovirus).
Single-stranded, negative-sense, helical RNA.
Identified by surface antigens: HA (hemagglutinin) and NA (neuraminidase).
Page 17: Categories of Influenza Virus
Three categories: A, B, and C.
Influenza A: Causes epidemics and pandemics; bird reservoir.
Influenza B: Less severe; only epidemics. No animal reservoir.
Influenza C: Mild illness; does not cause epidemics.
Page 18: Vaccination Needs for Influenza
Annual vaccination is crucial.
Variability in surface antigens (H and N).
13 different H and 9 different N spikes exist, resulting in 117 combinations.
Page 19: Antigenic Drift
Minor changes (point mutations) lead to antigenic drift:
Diminished immunity over time.
Genetic reassortment occurs if multiple viruses co-infect a host.
Page 20: Antigenic Drift Details
Overview of antigenic drift:
Gradual changes in H and N spikes over years.
Page 21: Antigenic Shift
Antigenic shift is significant in influenza type A:
Results in abrupt changes due to different viral strains recombining.
Page 22: Flu Pandemics Originating in China
Factors contributing to flu pandemics:
Close quarters of birds, pigs, and people increase strain opportunities.
Page 23: Influenza Reassortment
Concept of reassortment among viruses discussed.
Impact on potential outbreaks illustrated by example.
Page 24: Citizen Science
Introduction to the concept of citizen science.
Page 25: Case Study Introduction
Introduction to Case Study #1: Matt Groening.
Page 26: John's Symptoms
John experiences severe sore throat, fever, headaches, and nausea.
Attributes symptoms to stress and exams.
Page 27: Seeking Medical Help
Friends convinced John to see a doctor after persistent symptoms.
Page 28: Should John Attend Class?
Varied opinions on whether John should continue attending class:
Potential risk of spreading illness vs. need to keep up with studies.
Page 29: John's Decision to Visit the Doctor
After a week, John visits the doctor realizing he isn't improving.
Page 30: Diagnosis
John diagnosed with strep throat; prescribed antibiotics and treatment plan.
Page 31: Recovery
John followed treatment, felt better after three days; sore throat and coughing resolved.
Page 32: Strep Throat Overview
Strep throat explanation:
Caused by group A streptococcus.
Symptoms: sore throat, fever, headaches etc.
Typical onset period post-contact is 1-3 days.
Page 33: Treatment of Strep Throat
Combination of NSAIDs (for pain) and antibiotics.
Page 34: Antibiotic Mechanisms
Overview of antibiotic classes and mechanisms of action discussed.
Page 35: John's Decision on Antibiotics
Varied opinions about whether John can stop taking antibiotics early.
Page 36: Recurrence of Symptoms
After stopping antibiotics, John develops new symptoms before important exams.
Page 37: Decision on Antibiotic Use
John recalls previous antibiotic prescription amidst worsening symptoms.
Page 38: Should John Use Antibiotics Again?
Varied opinions on whether John should retake antibiotics after relapse.
Page 39: Seeking Help Again
John decides to revisit the doctor after continuous lack of improvement.
Page 40: Reasoning for Symptoms
John's symptoms likely unchanged due to bacterial resistance from incomplete antibiotic course.
Page 41: Resistance Development
Discussion on other factors contributing to bacterial resistance.
Page 42: Antibiotic Resistance Questions
Questions about responsibility for rising antibiotic resistance.
Page 43: Antibiotic Misuse Paradox
Differences in how antibiotics are used/abused across developing and developed countries.
Page 44: Environmental Impact
Commercial antibiotic use in animal feed contributing to environmental resistance.
Page 45: Hospital Resistance Issues
Overview of antibiotic-resistant infections in hospital settings (e.g., MRSA).
Page 46: Resistance at Home
Discussion on misuse of antibiotics and antibacterial products in home environments.
Page 47: Responsible Use of Antibiotics
Recommendations: complete prescribed regimens, use regular soaps, and proper hand hygiene.