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
16
Q
What was the cause of SARS?
A
- A novel Coronavirus (SARS coronavirus – SARS-CoV)
- Genetically traced to a colony of horseshoe bats (Rhinolophus sp.) in Yunnan province
• Isolated from: – Palm civets (Paradoxurus hermaphroditus)
17
Q
How do we control epidemics
A
- Epidemiological investigation & surveillance: International co-operation, Case definitions
- Identification of cause: International co-operation between laboratories
- Treatment of cases: International sharing of results
- Quarantine of suspected & isolation of confirmed cases
- Advice against un-necessary travel & screening air travellers
- Reduction of social interaction in affected areas
18
Q
Describe the Middle East respiratory syndrome coronavirus (MERS-CoV)
A
- Also called SARS-like virus, novel coronavirus or ‘Saudi
SARS’ - First known cases spring 2012. 2,605 lab-confirmed cases including 937 deaths (September 2012 – August 2023): [WHO] CFR 36%)
- Most cases male (86% in Jun – Nov 2019)
- Age 9/12 - 94 Y (median 56Y in Jun-Nov 2019)
- 27 countries have reported cases: Initial (& most – ca. 80%) cases in Saudi Arabia
19
Q
What was the epidemiology of MERS-COV?
A
- Transmission generally requires close contact
- Humans probably infected by direct or indirect contact with dromedary camels**
- Limited ability to transmit between humans: So far, observed non-sustained human-to-human transmission has occurred mainly in health care settings**
- Taphozous perforatus (Egyptian tomb bat) may be the original source of the virus
20
Q
Describe COVID-19 (SARS-CoV-2)
A
- Novel coronavirus infection
- First reported in Wuhan, China, mid-Dec 2019
- Possible association with a food market in Wuhan
- Seafood & many other types of animals, many alive, sold at the market
- 776,281,230 Covid cases & 7,065,880 deaths reported to
WHO as of 14th Sept 2024
21
Q
Describe SARS-CoV-2 as a virus
A
- A Baltimore class IV +ve-sense single-stranded RNA virus
- Primarily spreads between people through close contact and via respiratory droplets and aerosols produced from coughs or sneezes
- Mainly enters human cells by binding to the receptor Angiotensin Converting Enzyme 2 (mACE2).
22
Q
What are the origins & Phylogenetic’s of SARS-CoV-2?
A
- Comparisons of the genetic sequences of this virus and other virus samples have shown similarities to SARS-CoV (79.5%) and bat coronaviruses (96%), indicating that an origin in bats is likely”.*
- The hypothesis that 2019-nCoV has originated from bats is very likely
23
Q
Why is SARS-CoV-2 a variant of concern?
A
- A category used for variants of the virus where mutations in their spike protein receptor binding domain (RBD)
- Substantially increase binding affinity while also being linked to rapid spread in human populations
24
Q
List the characteristics of variants of concern
A
- Increased: transmissibility, morbidity, mortality, risk of particular conditions (e.g. Long Covid, multisystem inflammatory syndrome), affinity for particular demographic or clinical groups
- Increased ability to: Evade detection by diagnostic tests, Evade natural immunity, Infect vaccinated individuals
- Decreased susceptibility to: Antiviral drugs, Neutralising antibodies
25
What was the reported case and deaths numbers for Covid 19?
- 24,987,768 Reported cases in the UK and Northern Ireland
- 232,112 reported deaths in the Uk and Northern Ireland
26
How was the COVID-19 infection transmitted?
- Mainly aerial transmission via small droplets or aerosols (Sneezing)
- Direct physical contact
- Can spread from infected people and from individuals who remain asymptomatic
- People remain infectious for up to 10 days in moderate cases & 2 weeks in severe cases
- Risk of transmission via forties now considered low
27
What are the non-pharmaceutical interventions for the control of Covid-19?
- There is clear evidence from studies conducted during the pandemic that the stringent implementation of packages of NPIs was effective in some countries in reducing the transmission of COVID-19
- There is also evidence for the effectiveness of individual NPIs, although, especially as the pandemic progressed and the virus became more transmissible, NPIs became less effective in controlling the transmission of SARS-CoV-2
- A common denominator of the evidence is that NPIs were, in general, more effective when the case numbers and the associated transmission intensity of SARS-CoV-2 were lower.
28
Describe NPI’s and non Covid infections
- Seemed effective against many other respiratory infections
- During Covid, flu & other RTI numbers were very low. ‘Flu levels were the lowest recorded in
the southern hemisphere in the ‘flu season 2020
- ‘Flu levels in the USA declined sharply within 2 weeks of introduction of COVID-19 mitigation measures
- Several possible reasons: Reduced transmission, Better vaccination, Fewer samples taken/tested, Laboratories redirected
29
How did Covid vaccines help to control covid 19?
- Since the introduction of vaccination programmes against Covid-10:
- Numbers of deaths due to Covid-19 and hospitalisations are much lower compared with earlier peaks before vaccination and when vaccine coverage was low.
- The current vaccines do not prevent all infections. They do reduce severity of infection & likelihood of death.
30
What did COVID-19 cause in the scientific world?
- Very large numbers of scientific papers produced to date on Covid-19
- Large amounts of misinformation/disinformation on the web
