4 reasons we're seeing more infectious disease outbreaks around the world

MERS, H1N1, swine flu, chikungunya, Zika: Another virus with a peculiar name always seems to be right around the corner, threatening to become a pandemic.

Over the past decade, the World Health Organization has declared four global health emergencies. Two of them were in the past two years: the Ebola epidemic in West Africa and the Zika outbreak that's spread through the Americas.

If that seems like a lot, it is. Researchers who charted the rise of infectious diseases from 1980 to 2010 in the journal The Royal Society in 2014 found that outbreaks have indeed become more common in recent decades:

Many of the pathogens that spark deadly outbreaks aren't new. Researchers have known about Zika since the 1940s and Ebola since the 1970s. Some of these viruses have evolved with humans for hundreds or thousands of years.

But viruses, bacteria, and fungi can now spread around the world with greater effectiveness and speed than ever before. And when they turn up unexpectedly in new places, they catch doctors and health systems — and people's immune systems — off guard.

The Royal Society

The global number of human infectious disease outbreaks and richness of causal diseases, from 1980 to 2010. Outbreak records are plotted with respect to (a) total global outbreaks (left axis, bars) and total number of diseases causing outbreaks in each year (right axis, dots), (b) host type, (c) pathogen taxonomy, and (d) transmission mode

publish - by Julia Belluz on May 31, 2016

see more at: http://www.vox.com/2016/5/31/11638796/why-there-are-more-infectious-disease-outbreaks