Global Human Pandemics



Concern over the recent spread of the mosquito-borne Zika virus has alarmed health officials throughout the world. While Zika itself is rarely a serious illness, the World Health Organization is studying whether the virus is causing an increase in serious birth defects and a rare neurological disease.  The outbreak is currently focused in Central and South America, raising additional concerns about the upcoming summer Olympics in Brazil.  Join Active Minds as we seek to understand the current threats by examining both the science of how diseases spread as well as the history of pandemics.

Key Lecture Points

  • Global human pandemics often begin as zoonoses, diseases that normally inhabit animals.  The majority of animal diseases are not transmissible to humans or if transmissible, cause no, or mild, illness. Sometimes, an animal pathogen can mutate into a form that is transmissible to humans and causes severe illness.
  • Three conditions must be met for the emergence of a human pandemic: a new disease must emerge that the population has no immunity against, the disease agent must infect humans and cause serious illness, and the disease agent must spread easily among humans and does so across a large geographic area.
  • The first historically documented pandemic was the plague of Athens in 430 B.C.  The plague is believed to be caused by the bacteria Salmonella Typhi, the cause of typhoid fever.  Since then, notable pandemics have included the bubonic plague of the 1300’s which spread by fleas from infected rats and killed one third of the population of Europe.  More recently, the 1918 Influenza pandemic killed 40 – 100 million people worldwide having originated in Kansas as an avian influenza virus.
    And AIDS has infected 78 million people worldwide, killing more than 39 million, with Sub-Saharan Africa being hit particularly hard.
  • In May 2015 Brazil began to report increasing numbers of Zika virus infections.  Although the symptoms are mild in most cases, Brazilian doctors saw an alarming increase in the number of babies being born with microcephaly, a condition in which the head and brain are abnormally small.  The WHO and CDC found strong scientific evidence that the Zika virus causes microcephaly and Guillain-Barre syndrome.  Pregnant women are advised to avoid travel to the Zika-infected areas of Latin America and Central America.
  • Zika is transmitted by the Aedes mosquito that thrives in hot and humid climates and is present throughout the Western Hemisphere.  There is no treatment or vaccine for Zika so the battle against the current epidemic has centered on mosquito eradication.
  • As the Zika virus continues to spread throughout the Americas, fears increase that the 2016 Summer Olympics, scheduled to be held in Brazil, will be the platform for global transmission of the virus.

Exploration Questions

  • What are major challenges the world faces in fighting a potential pandemic?
  • What steps should be taken to meet those challenges in the event of a pandemic?
  • In what ways does the modern era of technological advances help the fight against pandemics?  Hinder it?
  • What makes the current Zika epidemic so difficult to contain?  How is it different from previous pandemics?

Reflective Question

  • Have you ever been subjected to a quarantine or know someone who was?  If so, what was the experience like?
  • Do you think Zika will become a major threat in the US?  Why?  Why not?

More to Explore

Books for Further Reading

  • Barry, John M. The Great Influenza: The Epic Story of the Deadliest Plague In History. Penguin Books.  2005.  560 pages.  This book chronicles the 1918 influenza pandemic and the efforts of America’s top physicians to find the cause, control the spread and find a cure.
    Click here to order
  • Preston, Richard. The Hot Zone: The Terrifying True Story of the Origins of the Ebola Virus. Anchor, 1995. 448 pages.  This book tells the story of a military SWAT team of soldiers and scientists who are mobilized to stop an Ebola outbreak.
    Click here to order
  • Quammen, David. Ebola: The Natural and Human History of a Deadly Virus. W. W. Norton & Company, 2014. 128 pages.  The author describes Ebola’s history and the search to find the virus’ host animal.
    Click here to order
  • Casterson, Scott. Zika Virus: A Guide to Protect Yourself and Family. Createspace Independent Publishing Platform, 2016.  34 pages.  Provides information on what Zika is, how it is spread and how to protect yourself against the virus.
    Click here to order