Since the hook-and-loop shape of the deadly Ebola virus – transmitted from bats to monkeys to people – was first seen under a microscope in 1976 (pictured infesting a monkey kidney cell), flu has killed nineteen million people, compared to less than two thousand Ebola deaths. Killing its hosts before it can spread far, Ebola is much easier to contain and harder to transmit than airborne flu because it passes in body fluids. But as ever-expanding human population centres encroach on ecosystems, epidemiologists fear new cross-species infections, or zoonosis. The bubonic plague, which killed one-third of Europe’s population in the fourteenth century, was brought by rodents via the Silk Road. While in 2002, the airborne SARS virus outbreak – traced to a civet cat on sale in the animal markets in Guangdong, China, from where it infected eight thousand humans worldwide and killed 774 – gave a foretaste of future pandemics helped by air-travel.
Written by Tristan Farrow
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences (the new name for the MRC Clinical Sciences Centre) the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.