Scientists Are Just Now Figuring Out The Mysterious Disease That Nearly Wiped Out The Aztecs.

 Scientists Are Just Now Figuring Out The Mysterious Disease That Nearly Wiped Out The Aztecs.

For hundreds of years, history left us wondering what disease killed the Aztecs in the mid-1500s. Many assumed the Aztecs were one of many Central American groups to be wiped out by European diseases like smallpox. However, DNA testing has unearthed new evidence about what really killed 80% of the Aztecs. 

Scientists extracted DNA from Aztec teeth, and discovered the presence of a strand of Salmonella. Research on climate change in Mexico at the time indicates droughts could have precipitated the spread of disease. Some things remain unexplained, however; only continued research can explain how a massive epidemic ravaged the Aztecs and whether the invading Spanish introduced something fatal to the population. 

An Infectious Bacteria Was Responsible For Wiping Out Native Populations

For many years, scientists theorized about what could have caused the virulent epidemic that . Some thought it was something like Ebola, while others assumed it was diseases brought by Spanish explorers.

In January 2018, researchers discovered at least some of the Aztec population died from a strain of Salmonella called Paratyphi C, which presents itself as typhoid fever. Paratyphi C could have been spread via food or water.

Others suspect this strain of Salmonella was spread via rodents. The Spanish forced the Aztecs into deplorable working conditions, putting them in a compromised physical state and in closer proximity to rodents. 

DNA From Teeth Helped Piece Together The Mystery

By studying DNA from Aztec teeth, scientists discovered that Paratyphi C was responsible for the death of a portion of their population. German scientists examined the DNA taken from 29 skeletons in Mexico, and found the lethal bacteria.

According to Åshild Vågene, one of the contributing researchers at the Max Planck Institute for the Science of Human History, skeletons typically do not show visible marks or traces of disease. In this case, they were able to use a new screening technique, the Megan Alignment Tool (MALT), to identify the Salmonella DNA sequences. 

There Is Still More DNA Testing That Needs To Be Done 

As groundbreaking as the DNA evidence of a bacterial infection may be, it's still only DNA from 29 deceased Aztecs out of the millions who died. Moreover, a Salmonella-like condition wouldn't cause bleeding from nearly every orifice. Some reports say the Salmonella bacteria was actually only found in 10 skeletons. There's also only one known burial site where anyone with the disease - known locally as cocoliztli - was buried. More burial sites need to be tested before anything can be said for certain. 

The Salmonella Still Does Not Explain The Bleeding Orifices

Some scientists believe the Aztecs perished due to a blood-borne illness. Though we now have at least a partial answer to the deaths of 80% of the population, the Salmonella infection doesn't explain the facial bleeding. 

Francisco Hernandez, who was the physician of King Phillip II, provided a very descriptive written account of the condition affecting the Aztecs. Symptoms included fever, headaches, vertigo, dark urine, black tongue, large nodules on the neck and face, neurological problems, and, most notably, bleeding from the eyes, nose, and mouth.

Researchers accept Hernandez's description, as he was arguably the most medically knowledgeable person of the time. These symptoms have yet to line up with one disease specifically. 

Roughly 15 Million People Died In Five Years

Starting in 1545, about 15 million people died over the course of five years. To put that number in perspective, 20 million people died from the bubonic plague in just a little under a decade. While these numbers and time spans are close, it is important to consider the 15 million who lost their lives to this disease were concentrated in Mexico, whereas the Black Death spanned all of Europe. 

The Aztecs called this destructive disease cocoliztli, and it killed in a matter of days. Victims of this illness ran a high fever and then bled from the eyes, nose, and mouth.

Climate Conditions Didn't Help The Aztecs

New evidence has shown cocoliztli was worsened by climate change. Between 1545 and 1576, there was a "megadrought" that spanned the entire continent. It was the worst drought in Mexico for over 600 years.

Cocoliztli was notably absent from warmer, wetter areas like the Gulf of Mexico. Researchers were able to use tree ring evidence to figure out how much rain fell during those years, and they discovered a correlation between the drought and the massive deaths associated with cocolizti.

Human Sacrifice And The Conquistadors Also Wiped Out Many Aztecs

While a large number of the Aztecs succumbed to cocliztli and smallpox, it wasn't the only thing wiping them out. Many were killed in the form of human sacrifice. 

The amount of people lost to human sacrifice is still a mystery, but some scholars estimate up to 20,000 people a year were killed in the name of ritual. In July 2017, a tower of 650 skulls of women and children was found in what was formerly Tenochtitlan (now Mexico City).

Historians knew the Aztecs tried to scare the Spanish with these towers of skulls, but they expected to find the skulls of warriors. Sacrifices, plus the loss of 25% of the population to smallpox, put the Aztecs at a disadvantage already when it came to fending off the Spanish. Combined with the mysterious bleeding epidemic, the Aztecs did not have a strong chance of overpowering the Conquistadors. 

European Explorers Brought Over A Lot Of Diseases

While European explorers are to blame for introducing diseases like smallpox to native populations, it looks like they also carry the blame for Salmonella. Scientists tested skeletons that had been buried prior to the arrival of the Spanish, and those remains showed no evidence of the fatal bacteria.

It's worth noting, however, only five skeletons were tested. The bacteria hasn't otherwise been found in Mexico, but it was found in remains in Europe. Experts who were not involved in the study say it is likely the Spanish introduced the bacteria to Mexico, given the severity with which it affected the native Aztec population. 

 

The Aztecs Weren't The Only Native Population To Suffer From Widespread Disease

Regardless of what exactly wiped out 80% of the Aztecs, whether it was Salmonella or a rat-borne illness related to climate change, they were not the only native population to suffer devastating consequences at the hand of disease.

Prior to the arrival of Europeans, North America was largely free of diseases, especially aggressive ones like smallpox. Direct contact with European settlers wasn't even required; the diseases spread on trade routes. In many cases, Europeans found completely empty villages by the time they ventured further into the New World. For many years, it was thought North America simply wasn't heavily populated; in reality, the Native Americans had already been killed off by diseases to which they had no immunity. 

The Type Of Salmonella We Have Today Isn't Going To Kill You.

Today's Salmonella is mainly contracted through food. The most common strains of Salmonella found in the US are S. typhimurium and S. enteritidis, not Paratyphi C, which is the strain that killed the Aztecs. Ground beef, poultry, and eggs should all be completely cooked before being consumed.

Another main cause of Salmonella is handling birds, baby chicks, or reptiles (particularly turtles, which have long been linked to Salmonella outbreaks)..

Even if you do get Salmonella, most people recover quickly and without medical intervention. However, Salmonella can cause severe diarrhea, and that can be enough to land you in the hospital..