Epidemic & Pandemic

Epidemic is an unexpected increase in the number of disease cases in a specific geographical area (CDC). A pandemic is the worldwide spread of a disease (WHO, 2021).

Epidemic, pandemic and biological disasters are caused by hazards of organic origin, including bacteria, viruses, parasites, mosquitoes carrying disease-causing agents, and toxins or bioactive substances that occur naturally or are deliberately or unintentionally released. These hazards can lead to economic and environmental damage and loss of life, affecting people and animals at the population level as well as crops, livestock and endangered species of flora and fauna.

Epidemic diseases infect millions every year, and the COVID-19 pandemic illustrates the breadth and depth of the transformative impact of biological disasters. According to the WHO, the pandemic cost more than 6.8 million lives between March 2020 and March 2023,  and sparked the deepest economic recession in decades. The 21st century has already experienced several major infectious disease epidemics – old diseases such as cholera and plague have returned, and new ones like severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and H1N1 pandemic influenza have emerged. Further epidemics and pandemics are almost certain; the only unknowns are when and where a new lethal threat will emerge. Examples of other recent outbreaks, epidemics or pandemics include Ebola in the Democratic Republic of Congo (2018–2020) and West Africa (2013–2016), and the Zika virus in the Americas and Pacific regions (2015–2016).

Risk factors

Biological hazards are driven by a complex set of factors ranging from:

  • The ease of spread of biological hazards.
  • Exposure.
  • Susceptibility to becoming infected.
  • Capacity of individuals, communities, countries and international actors to reduce risks and manage the consequences of outbreaks.

Vulnerable areas

Biological hazards affect people at all levels of society and in all countries because

  • Infectious diseases travel easily across borders.
  • New pathogens continue to emerge by mutating, adapting and travelling from one species to another.
  • Biological hazards can be endemic, that is constantly present in a community – they pose low risk when the population is largely immune, but risk becoming epidemics when they are introduced to a new host community with no immunity.

Risk reduction measures

  • Ensure hospitals and health care can continue working when they are most needed.
  • Build resilient infrastructure.
  • Assess potential risks before planning and building hospital.
  • Have a hazard map to identify people at risk and their vulnerability.
  • Have a national or local plan in place to plan and anticipate.
  • Train staff on potential risks.
  • Install a monitoring system to predict and proceed to early evacuation.
  • Ensure contingency and response plans are in place at a national and local level to evacuate people on time.
  • Educate people and raise awareness on potential risks.

Other considerations

The HIV/AIDS pandemic, which has claimed more than 32 million lives since it was identified in 1981, shows how biological hazards often exploit the fault lines of society, spreading in the shadows of marginalization, disruption and conflict.

Droughts, floods, earthquakes and large displacements of populations also create conditions favourable for disease transmission.

Latest Epidemic & Pandemic additions in the Knowledge Base

This image shows a mosquito sitting on human skin.
The mosquito species Aedes albopictus, a known vector of chikungunya and dengue viruses, is establishing itself further northwards and westwards in Europe, according to the latest data from ECDC.
European Centre for Disease Prevention and Control
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This note intends to shift the discussion on pandemic and epidemic risk finance to a practical approach about the benefits of applying a disaster risk finance (DRF) lens to new financial mechanisms as they are developed and deployed.
Cover IDS
This paper assesses how the Covid-19 pandemic had ripple effects that extend beyond the domain of health risks into economic, social, and political domains.
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This study analyzed the seasonal association of weekly averages of meteorological parameters, such as wind speed, temperature, and air pollutant PM2.5, with confirmed COVID-19 cases and deaths in Baghdad, Iraq, for the period June 2020 to August 202
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The paper argues that navigating the twenty-first century requires a fundamental reboot of the logic for economic progress and human development, away from a dominant belief in efficiency and optimization.
In Mozambique, an uncharacteristically powerful cyclone has driven a surge in malaria cases. It’s a trend that’s becoming more common
Telegraph Media Group Limited
The establishment of a new organization in Japan integrating the National Institute of Infectious Diseases (NIID) and the National Center for Global Health and Medicine (NCGM) was officially decided on May 31 in preparation for infectious disease crises.
Mainichi Newspapers Co., Ltd., the - Mainichi Daily news, the
WHO and partners are launching a global network to help protect people from infectious disease threats through the power of pathogen genomics.
World Health Organization (WHO)

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