Why Are We Seeing an Explosion of New Viruses Like Zika?

Zika virus, Ebola, Middle East Respiratory Syndrome (MERS) coronavirus, Severe Acute Respiratory Syndrome (SARS) coronavirus, Nipah virus, Hendra virus, bird flu, swine flu — these viruses have all grabbed international attention in recent years. In the past few decades the world has witnessed an alarming surge in emerging infectious diseases (EIDs). Since 1980, new pathogens have emerged in the human population at a rate of about three each year.

Why are we seeing such a surge in new pathogens? One could argue that some of the pathogens may not be new at all; they could have circulated among humans for centuries and are just being identified for the first time because of increased surveillance and reporting. While this is true in a small number of cases, a study found that even after controlling for increased surveillance, there has still been a surge in EIDs in recent times.

In other words, the rise of new pathogens is very real.

So let’s look at the major reasons why we are seeing this rise:

First: human overpopulation. I think we need to change the phrase “breed like rabbits” to “breed like humans,” as no other species on this planet even comes close to the human reproduction rate. As our population grows, available land shrinks and more and more people are forced to live in crowded, urbanized environments, a situation ripe for the easy spread and emergence of infectious agents.

Second: increased travel. Our travels significantly increase our chances of catching a pathogen in one area and unwittingly transporting the infectious agent to another area, where it was never before seen and where little or no immunity exists.

Third: climate change. Vector-borne diseases are those that are spread through insects like mosquitoes, ticks, and spiders. A vector’s life cycle —> Read More