Rainforest tribe children

First contact

Contacting tribes can have catastrophic consequences

Isolated tribes making their first contact with the outside world are extremely susceptible to disease. No one in a tribe will have any immunity to diseases from the wider world, so infections spread rapidly throughout the entire population. In the last half-century hundreds of Brazilian tribes suffered massive losses following first contact with people from the outside world, with disease thought to be a major cause. Many tribes were destroyed completely. In tribes that survived the population was often reduced by more than 80 per cent.

Historically, much larger populations have also been devastated by foreign diseases. The Aztec Empire of Mexico was one of the most sophisticated on Earth, until, in the spring of 1519, Hernán Cortés and his small band of Spanish ‘conquistadors’ reached the country. They brought with them guns, swords and another, even more lethal, weapon: smallpox. The epidemic they unleashed on the indigenous people is said to have killed 3 million Aztecs in the region now known as Mexico.

Smallpox had an even more devastating impact on the Incas of Peru, drastically depleting their numbers several years before Francisco Pizarro and his conquistadors reached them. The story was similar in North America, where diseases from Europe wrought havoc among Native Americans. Some reckon that Old World diseases like smallpox may have been responsible for killing up to 95 per cent of the New World population.

Lead image:

Rainforest tribe children

Ben Sutherland/Flickr CC BY


About this resource

This resource was first published in ‘Epidemics’ in September 2007 and reviewed and updated in January 2015.

Health, infection and disease, Immunology, History
Education levels:
16–19, Continuing professional development