As our ancient ancestors and cousins evolved many infectious diseases evolved with them. Many of these pathogens have short unpleasant moments in our bodies today, there are some which once contracted remain with us for life.
These pathogens in particular can help shed light on their migrations and by extension, our ancient ancestors migration throughout planet earth. One of the advantages of a smaller genome is that we can see rapid evolution within a short space of time. Compared to human genomes, pathogens have had more time to build up enough differences and therefore makes it much easier to track movements.
The Arabian Slave Trade remains one of the darkest eras in African history. Little documentary evidence survives of population sizes and therefore the dramatic decline in population thanks to the slave trade, but estimates range from 17 million to 200 million people.
Very little research has been conducted to shed light on the evolution of communicable diseases especially sexually transmitted diseases. Hopefully future research will change this, but we have gained great insights into the effects of the Transatlantic slave trade. The human immunodeficiency virus spread throughout western Africa via the colonial rail networks which were laid down to help improve the ease of movement between important regions.
Little did the colonial powers know that they were facilitating the ease of movement of the HIV. The latter was not the only disease to make its way to the Americas, one of the most interesting paracites is Schistosoma mansoni whose lifecycle revolves around a freshwater snail, but the advent of freshwater fishing has meant that S. mansoni evolved a two-part lifecycle which now includes a human host.
The Herpes simplex virus has also benefited from migration movements brought about by colonialism. Humans are unique animals in having two different groups of the herpes simplex virus, one usually found around the mouth, the other found around the genital region. Dr. Charlotte Houldcroft of the University of Cambridge, UK set out bring together lines of evidence from epidemiology and archaeology to find out which hominin may have been the first to contract the genital herpes from the ancient ancestors of the chimpanzee.
Written by Charles T. G. Clarke