Past, Present and Future Pandemics

Pandemics: The Past, Present and Future
Dr. Vineeta Shukla
PGT (2nd year)
Dept of Community Medicine
IPGME&R

“Nothing on earth is more International than Disease.”
-Paul Russel

Learning objectives
Definition of Pandemic
Difference between Epidemic, Pandemic and Endemic
Pandemics of the past
Historical Models and what we learn from them
Features of a Pandemic: Stages, Mathematical modelling, SIR Model,
Basic Reproduction Number, Pandemic risks
COVID-19 Pandemic
Pandemic Mitigation
Possible Pandemics in future

Introduction
Greek word “Pandemick”
Pan= All; demos= People
Definition:
A Pandemic is defined as “an epidemic occurring worldwide, or over a
very wide area, crossing international boundaries and usually affecting a
large number of people.” [WHO]

Epidemic, Pandemic and Endemic
Epidemic
The occurrence in a
community or region of cases
of an illness or other health-
related events clearly in excess
of normal expectancy.
Example: Diarrhea outbreak
due to a common source
contaminated water tank.
Pandemic
Large-scale outbreaks of
infectious disease crossing
international boundaries, that
can greatly increase morbidity
and mortality over a wide
geographic area.
Examples: Swine Flu
Pandemic 2009, COVID-19
Pandemic
Endemic
Constant presence of a
disease within a given
geographical area.
Examples: Malaria is an
endemic disease in India,
Yellow fever is endemic in
Africa and South America

The Pandemics
that changed
History…

Timeline of Pandemics
430 BC Unknown disease (typhoid fever)
165 AD Antonine Plague
250 AD Cyprian Plague
541 AD Justinian Plague
1350 Black Death
1492 The Columbian Exchange
1665 The Great Plague of London
1817 First Cholera Pandemic
16th-20th century AD Small Pox
1855 The Third Plague Pandemic

1875 Fiji Measles Pandemic
1889 Russian Flu
1918 Spanish Flu
1957 Asian Flu
1968 H3N2 Pandemic
1981 HIV/AIDS
2003 SARS
2009 H1N1 Pandemic
2013 MERS
2015 Zika Virus disease
2018 Nipah Virus disease
2019 COVID-19 Pandemic

Plague of Athens (430-426 BC)
Earliest recorded Pandemic
Peloponnesian War
Countries affected: Libya, Ethiopia,
Greece
Symptoms: fever, thirst, bloody throat
and tongue, red skin and lesions
Impact: quarter of Athenian troops and a
quarter of Greek population killed
Exact cause: In January 2006,
researchers from the University of
Athens confirmed the presence of
Typhoid bacilli
European painting of 17th century AD
depicting Plague of Athens

Reconstructed 11-year-old girl who died during
the Plague of Athens and whose skeleton was
found in the Kerameikos mass grave
War took place between Athens and Sparta
from 431 to 404 BC

Antonine Plague (165–180 AD)
“Plague of Galen”
Possibly an early appearance of Smallpox
or Measles
Huns infected the Germans → Romans→
spread throughout the Roman empire
Symptoms: fever, sore throat, diarrhea and
pus-filled sores
Impact: killed a five million in total

Cyprian Plague (251-266 AD)
Named after the first known victim, the
Christian bishop of Carthage
Possibly a second outbreak of the Antonine
Plague
Symptoms: diarrhea, vomiting, throat
ulcers, fever and gangrenous hands and feet
Countries affected: Rome, Ethiopia,
Northern Africa, Egypt
Impact: 5,000 people a day killed in Rome
Saint Cyprian

Justinian Plague (541-750 AD)
The first recorded outbreak of
bubonic plague
First appearing in Egypt, it spread
through Palestine and the Byzantine
Empire, and then throughout the
Mediterranean.
Killed 10,000 a day
Caused Europe's population to drop
by around 50% 15th century painting showing a
Saint praying for those affected
with Justinian Plague

Black Death (1331-1353 AD)
Deadliest pandemic recorded in history
Bubonic plague outbreak
Started in Asia and moved westwards
Entering through Sicily when plague sufferers
arrived in the port of Messina, it spread throughout
Europe rapidly
About 20-30 million Europeans killed in six years;
200 million killed overall
Dead bodies became so prevalent that many
remained rotting on the ground and created a
constant stench in cities

The Columbian Exchange (1492)
Named after Christopher
Columbus
Widespread transfer of plants,
animals, culture, human
populations, technology, diseases,
and ideas between the Americas,
West Africa, and the Old World in
the 15th and 16th centuries
Diseases such as Smallpox,
Measles and Bubonic plague were
passed along to the native
populations by the Europeans

The Great Plague of London (1665-1666)
Bubonic plague epidemic
in England
Originated from Central
Asia
Killed an estimated
100,000 people—almost
a quarter of London's
population—in 18
months

First Cholera Pandemic (1817)
Originated in Russia
Spread through feces-infected water and
food
Passed to British soldiers who brought it
to India where millions more died
The British spread cholera to Spain,
Africa, Indonesia, China, Japan, Italy,
Germany and America
Vaccine was created in 1885, but
pandemics continued Jamie Ferran

Small Pox (16th – 20th century)
Disease originated 10,000 BC
Causative agent: Variola
Americas, Europe- worst affected
continents
19th and 20th century: about 500 million
deaths worldwide
Eradicated (1980)

The Third Plague Pandemic (1855-1960)
Bubonic Plague started in
China and moved to India
Claimed 15 million victims

Fiji Measles Pandemic (1875)
The Royal party visited Australia as a
gift from Queen Victoria
Brought the Measles disease to Fiji
island, and it was spread further
The island was littered with corpses,
scavenged by wild animals, and entire
villages were burned down, sometimes
with the sick trapped inside the fires
One-third of Fiji’s population, a total of
40,000 people, died

Russian Flu (1889)
First significant flu pandemic
Started in Siberia and
Kazakhstan→ travelled to
Moscow→ Finland→ Poland→
the rest of Europe
By the following year, crossed
the ocean into North America
and Africa
About 360,000 had died by 1890
A cartoon referring to the Russian Flu
Pandemic published in Trunk magazine
in 1892

Spanish Flu (1918-1920)
Deadliest pandemic after Black Death
Avian flu
Causative agent: H1N1 Influenza A Virus
First observed in Europe, the United
States and parts of Asia before swiftly
spreading around the world
Outbreak in Madrid led to the pandemic
being called the “Spanish flu”
Unusual high mortality in young adults
500 million affected, 50 million deaths
worldwide; a total of four waves
Spanish Flu ward in Kansas

Asian Flu (1957)
Causative agent: H2N2 Influenza A
Virus
First reported in Singapore, Hong
Kong and coastal cities of U.S
About 14,000 people died in
England in six months
A second wave (1958) caused an
estimated 1.1 million deaths
globally

H3N2 Pandemic (1968-1970)
Also called the Hong Kong flu
Causative agent: H3N2 strain of the
influenza A virus
One to four million people killed
globally

HIV/AIDS (1981- continuing)
AIDS was first observed in American gay
communities
About 35 million people worldwide have
died of AIDS since its discovery
Treatments have been developed to slow
the progress of the disease
Cure is yet to be found

SARS Pandemic (2002-2004)
First identified: Guangdong province, China
Causative agent: SARS Corona virus
Possibly started with bats, spread to other animals and then to humans
in China, followed by 26 other countries
Symptoms: Dry cough, fever, malaise and headache
About 8,096 people were infected with 774 deaths
Only 3 cases reported from India

Countries with deaths
Countries with cases
Map showing countries affected with the SARS Corona virus in 2003

Swine Flu Pandemic (2009-2010)
H1N1 Influenza Virus A Pandemic
Lasted for 19 months
H1N1 was a new strain formed as a
result of reassortment of bird, swine,
human flu virus and Eurasian pig flu
virus (term “swine”)
About 700 million people were
infected worldwide
India : 44,987 cases of swine flu
confirmed with 2728 deaths
>4000 cases
2000-4000 cases
1000-2000 cases

MERS Virus Pandemic (2012-2013)
Causative agent: Corona virus (MERS-CoV)
First identified: Saudi Arabian businessman
Countries affected: Jordan, Saudi Arabia, Qatar, the UK, Germany,
the UAE, Tunisia, France and Italy
Case fatality was higher than SARS

Ebola Virus Outbreak (2013-2016)
Most widespread outbreak of Ebola virus
disease
Ebola haemorrhagic fever; IP: 2-21 days
Guinea, Liberia and Sierra Leone
Animal to human transmission: through
infected bats
Human to human transmission: through
bodily fluids (blood, urine, semen)
28,646 cases reported worldwide with 11,323
deaths
Ebola Virus

Zika Virus Disease (2015-2018)
Causative agent: Zika virus
(Flavirius); IP: 3-14 days
Transmitted through bite of Aedes
aegypti, can also be sexually
transmitted
Transmitted from pregnant women
to the foetus (vertical transmission)
and causes microcephaly
Zika infections in adults can cause
Guillain–Barre syndrome
About 157 cases reported from India
in 2017 and 2018 (Rajasthan,
Gujarat and Tamil Nadu)

Nipah Virus Outbreak (2018)
Causative agent: Nipah virus (Genus Henipavirus)
First appeared in Malaysia in 1998 in pigs and pig
farmers
Linked to consumption of raw date palm sap (toddy) and
eating of fruits partially consumed by bats and using
water from wells inhabited by bats
IP: 4-14 days
Cases in India: Outbreak in Siliguri (2001), Nadia (2007);
Kerala in (May 2018, 17 deaths) and one case in June
2019 in Kerala (recovered)
Symptoms: Fever, cough, headache, shortness of breath
and confusion
Complications: Encephalitis and seizures

Historical models
The Leitmotiv Model of Markel
Rosenberg’s Four Act Model

The Leitmotive Model of Markel
The public understanding about how a disease is transmitted will affect the
course of a pandemic (Miasmatic Theory)
The economic consequences of the event influences the public’s response
to the crisis
The extent and speed of travel of both people and goods are major factors
in the spread of the pandemic disease
Microbes that kill relatively few people, but do so quickly like Ebola, get
more attention than ongoing pandemics that kill millions year after year
like the HIV pandemic
34

Media coverage which can both inform and misinform the public,
influences the course of the pandemic
Governments will often try to conceal outbreaks from the world at large
typically in an effort to protect against economic losses and setbacks
Undesirable social groups may be blamed for an epidemic or unfairly
treated

The Four Act play of Rosenberg
Progressive revelation: in which members of a community gradually
begin to acknowledge causalities resulting from the spread of a
particular contagious disease
Managing randomness: in which community members seek explanation
of often religious nature for the seemingly arbitrary profile of infection
Negotiating public response: in which community members demand
collective answers
Subsidence and retrospection: often leading to complacency as the
memory of the events fades over time
36

Learnings from historical models
The recent economic packages conceived and declared immediately by
various governments is also based on historical learning that economic
activities determine the course of the pandemics
The lower mortality rate in mainland China during the Spanish Flu was
attributed to traditional medicine usage – an area needs to be explored even
in current context
The current usage of antibiotics and antivirals are inspired largely from
experiences during the SARS pandemic and Ebola outbreak; drugs like
Remdesivir, originally developed during the Ebola outbreak is being re-
explored during this COVID-19 pandemic
37

Stages of Pandemic
In 2009, WHO applied a six-stage classification
How a novel influenza virus moves from the first few infections in
humans through to a pandemic

Mathematical modelling of Infectious diseases
How infectious diseases progress to show the likely outcome of an
epidemic
Find parameters for various infectious diseases and use them to
calculate the effects of different interventions, like mass vaccination
programmes
Two types of epidemic models: Stochastic and Deterministic
The Kermack–McKendrick epidemic model (1927) describes the
relationship between susceptible, infected and immune/recovered
individuals in a population

The SIR Model
N=S(t)+I(t)+R(t)

Reduce rate of infection (β) to flatten the curve.

Basic Reproduction Number (R0)
Measure of how transferable a disease is
Average number of people that a single infectious person will infect over
the course of their infection
R0 > 1: each person on average infects more than one other person, so the
disease will spread
R0 < 1: each person on average infects less than one other person, so the
disease will die out
R0 = 1: each person will infect on average exactly one other person, so the
disease will become endemic

Calculation of R0
R0= (βS)/γ
β: Rate of transmission
S: No of susceptibles
γ: Removal rate (recovered/died)

R0 of some infectious diseases
Disease R0
Measles 12-18
Chicken pox 10-12
Poliomyelitis 5-12
COVID-19 2.79 – 3.28*
Ebola virus disease 1.5-1.9
Sanche S, Lin YT, Xu C, Romero-Severson E, Hengartner N, Ke R. High Contagiousness and
Rapid Spread of Severe Acute Respiratory Syndrome Coronavirus 2. Emerging Infectious
Diseases. 2020; 26(7): 1470–1477.

Risks
Pandemics appear to be increasing in frequency, particularly because of the
increasing emergence of viral disease from animals
Pandemic risk is driven by the combined effects of “Spark risk” (where a
pandemic is likely to arise) and “Spread risk” (how likely it is to diffuse
broadly through human populations)
Some geographic regions with high spark risk, including Central and West
Africa, lag behind the rest of the globe in pandemic preparedness
Probability analysis indicates that in any given year, about one percent
probability exists of an influenza pandemic

Background
November 2019: First identified in Central Market of Wuhan, Hubei,
China
December 2019: WHO is informed of cases of Pneumonia of Unknown
Etiology
30 January 2020: WHO declared the outbreak a Public Health Emergency
of International Concern (PHEIC)
11 March 2020: WHO declared it as a Pandemic
As of 5 September 2020, more than 26.6 million cases reported across 188
countries
More than 874,000 deaths; more than 17.7 million people have recovered

COVID-19 worldwide (5th September 2020)

COVID-19 in India
Confirmed cases in India till
September 7th, 2020
Total cases: 4.4 million
(September 7th, 2020)
Active cases: nearly 0.9 million
Deaths: About 73,000

COVID-19 in West Bengal
Confirmed cases in West Bengal till
September 2nd, 2020
Total cases: 189,000
Active cases: About 23000
Deaths: About 3680
(September 7th,2020)

Impacts
Commercial establishments
Education
Economy
Transport
Exodus of migrant workers
Loss of jobs
Food crisis
Sports

Epidemiological triad
Agent
Host Environment
COVID-19
Humans Surface/Gathering
Mask
Use
Handwashing/
Sanitization
Social distancing

Causative agent
Severe Acute Respiratory Syndrome
Coronavirus-2 (SARS-CoV-2)
Enveloped, ss-RNA virus
Seventh known coronavirus in
humans
Belongs to the same phylogenetic
family as the 2002 SARS and the
2012 MERS-CoV-2
Presumed – but not confirmed – to
have originated in bats given a
remarkable (89-96%) genomic
homology to bat coronaviruses

Transmission
Incubation period: 2-14 days
Period of infectivity: 2 days prior to
symptoms to 14 days
Transmitted via droplets (may be aerosols)

Clinical Presentation
Respiratory infection- variable clinical course
Symptoms: fever, cough, dyspnea, sore throat but also, interestingly,
anosmia, dysgeusia or none at all
Viral pneumonia which may progress to Acute Respiratory Distress
Syndrome (ARDS) along with cardiogenic shock
Most vulnerable- those of advanced age or with significant comorbid
conditions, such as cardiovascular disease, COPD and hypertension

Diagnosis
Gold standard: rRT-PCR
Sample: Nasopharyngeal swab (alternatives-
oropharyngeal, nasal, sputum)
Rapid Antigen Test
CT-Scan of Chest: Bilateral multilobar
ground glass opacities
CBC: Leucopenia with lymphocytopenia
Widal test: Rising titre noted

Treatment
Asymptomatic: Home isolation
Mild Cases : Symptomatic treatment; home isolation
Moderate to Severe Cases: Admission; oxygenation, mechanical
ventilation (if respiratory failure)
Treatment of co-morbidities simultaneously

Prevention
Specific: Vaccine
Prophylactic measures: To decrease and delay the epidemic peak
(flattening the curve)
Measures to reduce spread of infection:
a. Staying at home
b. Wearing a mask in public
c. Avoiding crowded places
d. Social distancing, restricting travel
e. Handwashing with soap and water (20secs)
f. Avoiding touching eyes, nose and mouth with unwashed hands

Personal Protective Equipment (PPE): For healthcare professionals
Face masks: Limit the volume and travel distance of expiratory droplets dispersed
when talking, breathing, and coughing

Pandemic Mitigation
Situational awareness: includes disease surveillance and monitoring of
public health activities
Reducing pandemic spread:
1. Curtailing interactions between infected and uninfected population
2. Reducing infectiousness through treatment and infection control
practices
3. Reducing susceptibility of uninfected individuals

Mitigation (continued)
Pre-pandemic period: Stockpile building
Public health workforce training
Spark period (as pandemic starts): Initial outbreak detection
Pathogen characterization/lab confirmation
Contact tracing, isolation
Spread period (after pandemic starts): Global pandemic declaration
Risk communication
Stockpile deployment
Preventive measures
Treatment of cases
Vaccine administration

The Future
Possible Pandemics in future
1. Corona virus infection
2. Influenza pandemics (Avian flu)
3. Viral haemorrhagic fever (Ebola and Marburg virus)
4. Zika virus disease
5. Nipah virus disease
6. Hanta virus infection (or Andes virus)
7. West Nile fever (West Nile virus, Culex sp.)
8. Bunya virus infection (Rift Valley disease)

Conclusion
History has taught us that some pandemics can be mitigated, some can
even be eliminated over sustained effort but some will remain and become
endemic to humans; we need to learn to live with them
Most important and obvious is to prepare for an economic downturn
Learnings from a pandemic can also be used to change human behaviour
and push for improved infrastructure
In an increasingly globalised commerce scene and in an interconnected
world, the butterfly effect will be more and more prominent in years to
come

References
1. Heath Kelly. The classical definition of a pandemic is not elusive. Bulletin of the World Health Organization 2011;89:540-541.
2. Endemics, Epidemics and Pandemics. Physiopedia [Internet]. Available from: https://www.physio-
pedia.com/Endemics,_Epidemics_and_Pandemics(last accessed on 09.09.2020)
3. Madhav N, Oppenheim B, Gallivan M, Mulembakani P, Rubin E Wolfe N. Disease Control Priorities: Improving Health and Reducing Poverty.
3rd edition. Washington (DC): The International Bank for Reconstruction and Development / The World Bank; 2017 Nov 27. Chapter 17.
Available from: https://www.ncbi.nlm.nih.gov/books/NBK525302/ doi: 10.1596/978-1-4648-0527-1_ch17
4. Past Pandemics. Centers for Disease Control and Prevention [Internet]. Available from: https://www.cdc.gov/flu/pandemic-resources/basics/past-
pandemics.html (last accessed on 09.09.2020)
5. Pandemics That Changed History. History.com [Internet]. Available from: https://www-history-
com.cdn.ampproject.org/v/s/www.history.com/.amp/topics/middle-ages/pandemics-
timeline?usqp=mq331AQFKAGwASA%3D&amp_js_v=0.1#aoh=15990510931472&referrer=https%3A%2F%2F(last accessed on 09.09.2020)
6. Institute of Medicine (US) Forum on Microbial Threats. Ethical and Legal Considerations in Mitigating Pandemic Disease: Workshop Summary.
Washington (DC): National Academies Press (US); 2007. 1, Learning from Pandemics Past. Available from:
https://www.ncbi.nlm.nih.gov/sites/books/NBK54171/ (last accessed on 09.09.2020)
7. Wikipedia contributors. Influenza pandemic. Wikipedia, The Free Encyclopedia [Internet]. Available from:
https://en.wikipedia.org/w/index.php?title=Influenza_pandemic&oldid=976842157. (last accessed 09.09.2020)
8. THE WHO PANDEMIC PHASES. Pandemic Influenza Preparedness and Response: A WHO Guidance Document [Internet] Available from:
https://www.ncbi.nlm.nih.gov/books/NBK143061/(last accessed on 09.09.2020)
9. Wikipedia contributors. Covid-10 pandemic in India. Wikipedia, The Free Encyclopedia [Internet]. Available from:
https://en.wikipedia.org/wiki/COVID-19_pandemic_in_India(last accessed 09.09.2020)
10. The Hindu. Preventing future pandemics: curb climate change and protect environment, says UN report [Internet]. Available
from:https://www.thehindu.com/sci-tech/preventing-future-pandemics-curb-climate-change-and-protect-environment-says-un-
report/article32010329.ece(last accessed 09.09.2020)

“He who has health, has hope;
and he who has hope has
everything.”
Thank you…

Past, Present and Future Pandemics

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