The conquest of Mexico, 16th- or 17th century Indian pictorial manuscript. Credit: Public domain
An analysis of ancient DNA published by eLife suggests that the transatlantic slave trade may've introduced pathogenic viruses to North America from Africa. This could have affected Indigenous communities.
These findings indicate that European colonists brought viruses such as smallpox and measles to North America. This caused major population declines in Native American communities. This new discovery provides additional information on the legacy of North American transatlantic slave trading.
Multiple outbreaks in Mexico in 16th-century Mexico claimed the lives of millions of Native peoples, Africans and Europeans. However, the exact cause of some of these outbreaks are not known," says Axel Guzmn Sols, the first author. He was a student at the International Laboratory for Human Genome Research at Universidad Nacional Autnoma de Mxico in Mexico and is currently a doctoral student at Mount Sinai's Icahn School of Medicine. "We wanted to know what viruses circulated in Mexico during that period."
Guzmn Sols and his team took ancient viral DNA from the teeth and buried it at a Colonial-era chapel and hospital. These victims included both Indigenous and African-born victims. This DNA was then used by the team to reconstruct the viruses' genomes from those samples. This allowed them identify the ancient human hepatitis B and human B19 virus from different individuals. They were able to compare the genomes of these viruses with other viruses and found that they likely originated from Africa.
"Our results indicate that the virus was introduced to America by colonists who were involved in the slave trade," said Daniel Blanco-Melo (co-senior author). He is a former postdoctoral researcher at Icahn School of Medicine in Mount Sinai, New York, and is now Assistant Professor at Fred Hutchinson Cancer Research Center, Seattle, U.S.A. "The unsanitary, cramped, and overcrowded conditions aboard the ships that carried millions of people across Atlantic was a favorable environment for the spread of disease." This gruesome practice probably introduced new pathogens into the lives of Indigenous people, who were not immune to them. He also said that colonists made Native Americans and Africans live in conditions that promoted spread of diseases and could have fuelled epidemics.
It is unclear whether the infected individuals were transported from Africa to North America, contracted the virus, or if they arrived in North America with the virus. It's also impossible to determine if the viruses were responsible for the deaths of the victims. It does show that the viruses were present in the affected population, and could cause severe disease.
"Our findings also indicate that multiple, new viruses were circulating simultaneously, which may explain why epidemics proved so fatal for Indigenous communities," Maria Vila-Arcos (principal investigator at the International Laboratory for Human Genome Research at Universidad Nacional Autnoma de Mxico) says. This work shows how paleovirology, a new field in paleovirology, can be used to help us understand more about colonial epidemics and the role of humans in spreading them.
Continue reading about Herpes simplex viruses: New relationships between history and epidemiology
More information: Axel A Guzmn Sols et al. Ancient viral genomes reveal the introduction of human pathogenic virus into Mexico during transatlantic slave trade. eLife (2021). Information for Journal: eLife Axel A Guzmn Sols et. al., Ancient viral genomes show that humans were introduced to Mexico by the transatlantic slave trade (2021). DOI: 10.7554/eLife.68612
