Pandemics (PART 2) Flashcards
1
Q
Describe the seasonal flu
A
- Outbreaks: Temperate climates - mainly in winter. Tropical regions - throughout the year
- Worldwide, 1 billion cases of which 3-5 million severe & 290,000 - 650,000 deaths every year*
- Estimated global annual attack rate 5%-10% in adults, 20%-30% in children
2
Q
Which groups are high at risk from the seasonal flu?
A
- High-risk groups include the very young, elderly, chronically ill
- In industrialized countries most deaths >65 years old
3
Q
Describe the seasonal flu statistics between 2020 - 2023
A
- Flu numbers very low 2020-22. Better vaccination? Covid protection. masks, spacing, lockdowns? Fewer samples taken? Laboratories redirected?
- 2022 numbers increasing, earlier than usual
4
Q
Describe the influenza surface antigens
A
- Haemagglutinin (HA): a glycoprotein that binds the virus to the cell that is being infected
- At least 16 different HA antigens of which 3 (H1, H2, H3), are found in human flu viruses
- Viral neuraminidase (NA): Enzyme that enables the virus to be released from the host cell
- Influenza viruses are characterised by the type of HA
and NA that they carry; hence H1N1, H5N1, H3N2 etc.
5
Q
How do we prevent influenza?
A
- Vaccination
- Good hygiene: Influenza viruses inactivated by sunlight,
disinfectants & detergents. Hand hygiene an important control measure - Isolation: Reduce transmission
- Health education
- Antiviral drugs
6
Q
Why does Influenza cause pandemics/panzootics? VD
A
- Readily transmissible
• Infective before symptoms appear
• Antigenic Drift & Shift
7
Q
Provide a brief history of the Spanish flu
A
- Strain of H1N1
- Broke out in 1918: 3 waves of infection, 2nd was the worst
- Estimated to have infected >30% of world population (ca. 500 x 106): Possible death toll 17 - 50 million people (up to
3% of world’s population) - CFR >2.5%, (CFR in other flu pandemics ca. 0.1%)
- Higher than expected mortality among healthy young adults
- Good intensive care not available. No vaccines, no antibiotics
- Causative organism unknown
8
Q
How did they fight the Spanish flu?
A
- Physicians tried everything they knew, everything they had ever heard of, …..bleeding patients, administering oxygen, … developing new vaccines & sera (chiefly against ….. Haemophilus influenzae …& several types of pneumococci).
- Only one therapeutic measure, transfusing blood from recovered patients to new victims, showed any hint of success.“
9
Q
What were the public health measures in the USA after the Spanish flu?
A
- Maritime quarantine
- Isolation of cases
- Face Masks
- Disinfection/Hygiene measures
- Social Distancing: closing schools, theatres & places of worship, Limiting public transport, Banning mass gatherings
10
Q
What was the anti mask league of San Francisco?
A
- Formed to protest the requirement for people in San Francisco, California, to wear masks during the 1918 influenza pandemic!
- Objections to the ordinance were based on:
- Questions of scientific data
- Infringement of civil liberties
11
Q
How did the H5N1 Avian flu almost cause a Pandemic potential? VD
A
- A highly pathogenic avian virus (HPAI – Highly Pathogenic Avian Influenza)
• underwent a shift in 2020 - led to a panzootic outbreak.
• badly affected the UK’s breeding seabirds
• Recent emergence in dairy cattle in USA
• Few human cases but high mortality
12
Q
List the key features of the H5N1 Avian flu
A
- H5N1 remains infectious after
- > 30 days at 0°C & 6 days at 37°C
- at ordinary temperatures can survive in the environment for weeks
- dust containing the virus can be infectious
- No highly effective treatment for humans,
- Oseltamavir (Tamiflu), can inhibit spread of the virus in the body
13
Q
Describe Coronaviruses as Pandemics
A
- From the Latin corona (crown / halo)
- Enveloped RNA viruses: Genomic size 26 - 32 kilobases, the largest for an RNA virus. RNA viruses have very high mutation rates
- Can cause diseases in mammals & birds: Usually mild respiratory infections in humans
- Several vaccines and drugs now approved for prevention or treatment of SARS-COV-2
14
Q
List the different coronaviruses we have previously come across
A
- SARS coronavirus (SARS-CoV): Cause of Severe Acute Respiratory Syndrome (SARS) (2003-4)
- Middle East Respiratory Syndrome coronavirus (MERS-CoV): June 2012 to July 2020: 2,577 cases with 935 deaths (CFR ca. 34%) in 27 countries
- NL63/NL/New Haven Coronavirus & HKU1: Newly described, affect humans but do not cause serious disease
- COVID-19 (SARS-CoV-2): First reported in Wuhan, China, mid-Dec 2019
15
Q
Describe SARS (Severe Acute Respiratory Syndrome)
A
- An acute respiratory disease
- 1st case - 45Y male in Guandong, China, 16/11/2002
- Virus identified 22/03/2003
- Last pandemic cases July 2003
- 30 countries involved
- 8,098 cases and 744 deaths worldwide (CFR = 9.6%)
- No cases reported since 2004
