Although the Aztecs were able to build complex architectural structures, they were absolutely unable to prevent diseases that were brought in by the Spaniards.
After the Spanish conquistadors arrived in Mexico in 1519, one of the worst epidemics in human history broke out in the once mighty Aztec civilization. During the hundred years that the Spaniards were on Indian land, the Aztec population was reduced from 25 million to 1 million. There are many theories about what exactly caused the devastating outbreaks of the disease, but no one knows for sure the cause. Many scientists are inclined to think that Salmonella was the cause of the mass extinction of the Indians.
Interesting scientific evidence
Recently, a team of scientists presented the first evidence of the existence of DNA from bacteria found in the bodies of victims who died in one of the worst outbreaks of the epidemic. They speculate that a species of Salmonella may be the culprit, in particular a rare strain known as Paratyphoid C.
Today, salmonellosis can be contracted from eating undercooked meat, poultry or eggs. The duration of the illness is about a week. The main symptoms are stomach cramps, nausea, vomiting, diarrhea, chills and fever. This is a disgusting disease, but it does not pose a danger to life.
But some strains of Salmonella bacteria can cause serious illnesses such as typhoid fever, and can even be fatal. One of the strains, known as Paratyphoid C, causes intestinal fever. If untreated, the disease can take the lives of up to 10-15% of people infected.
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At present, Paratyphea C is extremely rare and mainly affects people in developing countries, where sanitary standards are at very low levels. The outbreak of this deadly form of Salmonella may have contributed to the fall of the Aztec state in the 16th century, according to new DNA studies of the bacteria.
Major epidemics
In the decades after the arrival of the Spanish conquistadors, the Aztecs suffered several terrible epidemics of terrible diseases. In their native language, Nahuatl, the Aztecs called such outbreaks cocoliztli, which means seasickness. The largest epidemic is believed to have lasted from 1545 to 1550 and killed over 80% of the population. Another major outbreak occurred in 1576, bringing the total death toll between 7 and 18 million.
In an effort to find out what exactly caused these outbreaks, a team led by scientist Johannes Krause, an evolutionary geneticist at the Max Planck Institute for Human Science in Germany, decided to study burial in the highlands of the Oaxacans in southern Mexico. Scientists have extracted and sequenced DNA fragments from the teeth of 29 bodies buried at the site. The remains of twenty-four people belonged to the victims of the 1545-1550 epidemic.
Intriguing findings
After separating bacterial DNA from human DNA, scientists compared their results with more than 2,700 genomes of modern bacteria. They found that bacterial DNA obtained from several people matched the bacterial genus Salmonella and was ultimately able to reconstruct two genomes of the Paratyphi C strain of Salmonella enterica, one of two Salmonella species.
Previous research has shown that diseases such as typhus, smallpox and measles may be responsible for the mass deaths of the Aztecs. In 2002, researchers at the National Autonomous University of Mexico (UNAM) in Mexico City suggested that viral haemorrhagic fever combined with drought killed millions of Aztecs. The scale of the epidemic was comparable to the Black Death, as a result of which up to 20 million people died in Europe at the end of the XIV century. However, none of these preliminary hypotheses have been confirmed by DNA data, making the new study particularly intriguing.
The experts have the last word
According to ScienceAlert, the study has not yet been verified by experts, and other scientists collaborating in the field are likely to verify the results and weigh all the facts. At the very least, Avila-Arcos, an evolutionary geneticist at UNAM who was not involved in the new study, remains skeptical that Salmonella could cause so many deaths.
Evidence for the existence of salmonella in the Middle Ages
Another DNA study could provide additional information on the theory of the origin of Salmonella. This research study is led by microbiologist Mark Achtman of the University of Warwick in Coventry, United Kingdom. For analysis, a bacterial genome was taken from the remains of a young woman buried in a cemetery in Trondheim, Norway in 1200.
This provided the earliest known genetic evidence for the existence of the Paratyphi C species in Europe, more than 300 years before the Spanish conquered Mexico. Scientific research supports the possibility that Salmonella was brought to the New World by Europeans, with dire consequences for the Aztecs.
Maya Muzashvili