Whole villages wiped out, minor tribes completely erased, civilisations destroyed; millions of people died when the conquerors of the new world arrived with ‘old world’ diseases. There is no doubt that the Americas gained so much in the Columbian Exchange, the term used to describe the widespread exchange of animals, plants, culture, humans between the East and the West, and it was true, sadly, of infectious diseases. The Americas were said to be free of smallpox, typhus, measles, influenza, bubonic plague, cholera, malaria, mumps, yellow fever, and whooping cough, which were common throughout Europe and Asia when the Europeans arrived. However, the sailors, the explorers, the missionaries and later the colonialists also came in contact with diseases that they were too were not immune to.
Indeed, smallpox, that bears the brunt of the blame of the disaster that befell the indigenous populations of the Americas, is believed itself to have been brought to Europe by the Moors when they conquered and then ruled Hispania for 800 years. Europe’s ambitions in seeking a sea trade route to the Far East meant trading posts were set up along the coast of Africa and so the Europeans were introduced to African diseases such as sleeping sickness and yellow fever long before they introduced some of them mainly via the slave trade to the Americas. The World Health Organisation certified the eradication of smallpox in December 1979 after a long period of vaccination campaigns worldwide. It is the only human disease to have been eradicated though there have been others that have simply disappeared naturally such as English Sweat in 16th-century.
The Americas scenario was repeated in Southern Eastern Asia, Australasia and the Pacific Islands were these first world diseases ravished the populations to such a point that resistance to the invading Europeans was futile.
It is interesting to note that the furores into Africa, especially the North and East coast and Central Asia did not bring about such large scale deaths. This is probably because many of the infectious diseases may have affected humans in these parts for long periods of time and due to the fact that trade between these parts of the world had been going on for so long that immunity had spread over a large area. A notable exception is Cholera whose main symptoms are diarrhoea and vomiting caused by drinking or eating water or food that has been contaminated by an infected person. Originally confined to the Indian subcontinent, it spread to Russia in 1817, then to Europe and then to North America by 1834. It is now has become one of the most widespread and deadly diseases affecting 3-5 million people and causing over 100,000 deaths a year mainly in the developing world where good sanitation is an issue.
This is not to say that people in Europe, North Africa and Asia did not die from many of the diseases, for example smallpox accounted for 400,000 deaths a year in Europe during the 18th century, but that there was better resistance in the population. Despite this there have been many instances of epidemics and pandemics such as the seven cholera pandemics in the past 200 years.
For the sailor and the intrepid explorer, scurvy was the first curse to overcome. Long periods at sea without fresh fruit and vegetables led to open, suppurating wounds, loss of teeth, jaundice, fever, neuropathy and death for many. It is estimated that over 2 million sailors were lost to scurvy between the 14th century and the time that many navies introduced a means of supplying the missing Vitamin C in the 17th Century. Even the great explorers, Vasco da Gama and Ferdinand Magellan lost many of their seamen to this scourge. The British Royal Navy is regarded as the first to eradicate scurvy in the 1790s by the introduction of lemon juice to sailor’s diets.
It is really when the Europeans began to trade with and explore tropical and sub Saharan Africa that previously unknown infectious diseases were discovered. West Africa became known as “the white man’s grave” but even that did not stop the march of colonisation though it did lead to efforts being made to control and manage the diseases, at least in European populations.
One of the African diseases is Yellow fever (slang term “Yellow Jack”) which is an acute viral haemorrhagic disease transmitted by the bite of female mosquitoes. . It is believed to have been introduced to South America because of the slave trade in the 16th century. However, there are some claims that it existed in the Americas before the age of discovery. In the early days of exploration and colonisation, an outbreak of yellow fever would kill 100% of the Europeans it infected whilst many healthy Africans would survive it. Still today 90% of the world infections happen in Africa and it causes 30,000 deaths every year in unvaccinated populations. Being a tropical disease, yellow fever has remained within the world’s tropical zone excluding Asia.
Another one was Malaria, a mosquito-borne infectious disease of humans and other animals. It is a disease many people connect with Africa and that is because it is widespread and causes so many deaths on the continent. However, malaria was known to the Europeans and the Asians for centuries with the 1st recorded case appearing in China in 2,700BC. Malaria was so common in Rome that it was nicknamed the ‘Roman fever’ and is suspected to have played a role in the downfall of the empire. Today, it is estimated that malaria results in nearly one million deaths annually in the sub Saharan Africa, Asia, and the Americas.
The tsetse fly transmitted sleeping sickness, a parasitic disease of people and animals which is very widespread in sub Saharan Africa, covering about 37 countries and 60 million people. Some 48,000 people are said to have died of it in 2008 but it is believed that many cases go unreported. Sleeping sickness is believed to have by spread over large areas of Africa by the Arab slave trade in the 14th century.
The Europeans appear to have been lucky in that many of the new infectious diseases they discovered in Africa, could not be exported back home due to their tropical and sub-tropical nature. It affected those who chose or were forced to settle on the continent. However, the Americas did trade the Europeans a particularly virulent type of syphilis or the “Great Pox” though there are some scientists who believe that syphilis was present in the old world prior to that but went unrecognised.
Generally, many believe that it was brought back to Europe on one of Christopher Columbus’ voyages to the New World. There is evidence suggesting that the syphilis strain brought back from the Americas evolved in the European environment making it so much more deadly. Syphilis is a sexually transmitted infection but it can also be transmitted from mother to child during pregnancy or at birth. The first recorded outbreak of the disease in Europe was in 1494 in Italy during a French invasion and it went on to become a major killer from the 14th to the 17th century. Today it affects some 12 million people with more than 90% of cases in the developing world. The non-lethal but disfiguring syphilis-like pinta is a human skin disease endemic to Central and South America and would have affected explorers, traders and missionaries in those regions too.
Those who settled in the Americas would also have been affected by Chagas disease which is a tropical parasitic disease transmitted to humans and other mammals by a type of bug, contaminated food and sometimes from mother to child in pregnancy. Today, Changas disease affects millions of people in Latin America a few hundred thousand in the USA and Spain and causing about 20,000 deaths a year.
In here lies the history lesson that should warn us about the dangers of the transmission of disease. In today’s world, it so much easier for infectious diseases to spread and the recent cases of HIV/AIDS, SARS, bird or avian flu and swine flu are just examples of the dangers we face even in today’s world. There are many more serious diseases that have the potential to become widespread pandemics and our common humanity means that any fatal disease that develops and is transmitted has the potential to virtually wipe the whole human race of the planet.