As humans have spread across the world, so have many infectious diseases. Even in this modern era, outbreaks are nearly constant, although not every outbreak has reached the level of a pandemic as the Corona virus did.
Disease and illnesses have been for ages. It was after the growth of agrarian communities that the spread of these diseases increased dramatically.
Widespread trade helped in creating new opportunities for human and animal interactions that increased the spread of such epidemics like Malaria, leprosy, tuberculosis, smallpox, influenza, and others. More civilized the humans have become with trade routes, larger cities, and increased contact with different populations of people, animals, and ecosystems, the more likely pandemics occurred.
Despite the persistence of disease and pandemics throughout history, there was a gradual reduction in the death rate. Healthcare improvements and understanding the factors that incubate pandemics have been powerful tools in reducing their impact.
During the 14th century, the practice of quarantine began in an effort to protect coastal cities from epidemics- plague. The port authorities asked ships arriving from infected ports to sit at anchor for 40 days straight before landing in Venice. The origin of the word quarantine from the Italian word “Quaranta Giorni” which means 40 days.
While the interactions created through trade and urban life play a major role, it is also the virulent nature of particular diseases that lead to the trajectory of a pandemic.
With rise in global interactions and connections as a driving force behind pandemics from small hunting and gathering tribes to the metropolis, humanity’s reliance on one another has also lead opportunities for disease to spread.
Urbanization in the developing world is bringing more and more rural residents into denser neighborhoods, while population increases are deteriorating environment. Passenger air traffic has nearly doubled in the past decade. These macro trends have a profound impact on the spread of infectious diseases.
As Covid-19 reminds us, that infectious diseases haven’t vanished. There are more new infectious diseases now than ever: HIV, Sars, and Covid-19 have increased by nearly fourfold over the past century. Since 1980, the number of outbreaks per year has been tripled
There are several reasons for this – Over the past 50 years, the population has increased to double. So more human beings get infected and in turn to infect others, especially in densely populated cities. We also have more livestock now than we did over the last 10,000 years of domestication up to 1960 combined, and viruses can pass from those animals to us. The ability to get to nearly any spot in the world in 20 hours or less, and pack a virus along with us, allows new diseases to emerge and to grow. For all the advances we’ve made against infectious disease, our very growth has made us more vulnerable, not less, to microbes that evolve 40 million times faster than human beings do.