History of disease outbreaks and their impact 

JIMMY WHITWORTH: Outbreaks of infectious diseases have always been with us; from descriptions from Rome and from Athens in classical time, through plague in the Middle Ages, and then in the 19th century epidemics of cholera, and in the 20th century of influenza. During this course, we’re going to use the terms “outbreak”, “epidemic”, and “pandemic” a great deal. So let me clarify what we mean when we use these terms. Outbreak simply means more cases than expected of a disease in a specific place or population, over a given period of time. So in fact, this could just be a single case if it’s something unexpected.

For example, if it was a case of cholera in the UK in somebody who had never travelled abroad. Epidemic has, really, the same meaning as outbreak, but we tend to reserve that term for the larger types of outbreaks. And then a pandemic is a large epidemic, where it has spread into several countries or several continents. Going back to the history, with increasing trade, and pilgrimage, and war, there was increasing international travel, and it was recognised that this could bring back cases of plague. And so it was that, in the 14th century, city authorities in places like Venice and Dubrovnik established quarantine.

This was the holding of ships in port, not allowing them to dock, and of people at land borders who were isolated for up to 40 days to allow the incubation of any plague to have passed on. These measures aimed to provide health protection and health security for the citizens of these cities. By the 19th century, four diseases, plague, cholera, yellow fever, and smallpox, were covered by international agreements, with mandatory reporting allowing for international surveillance and response. From these agreements developed the International Health Regulations that were first issued in 1969.

Over time, it was recognised that with slow or limited reporting, with increasing rapid international travel, and with the emerging of other infectious diseases, there was a need to update these regulations.

All of this time, it was recognised that outbreaks were causing major loss of life, severe social upheaval and great financial losses. This drove medical advances, in particular the development of vaccines against conditions such as measles, polio, yellow fever, rubella, and diphtheria, all of which had caused major outbreaks in the past. The International Health Regulations were revised in 2005, and the focus changed from stopping diseases at international borders to developing national capacity to be able to detect and respond to outbreaks within their borders. You will hear more about this later this week in the step on global architecture. Meanwhile, epidemics continue to happen all the time and all around the world.

Just in the first two decades of the 21st century, we have had outbreaks of SARS (Severe Acute Respiratory Syndrome) meningitis, chikungunya, influenza, cholera, measles, MERS, which is Middle East Respiratory Syndrome, Ebola, Zika, and yellow fever. So, outbreaks have occurred throughout history and are still occurring today. You will learn more about this in the next step, which is about infectious disease outbreaks today.