Cocoliztli epidemics

Long ago, a big sickness hit Mexico.

The Aztec people called it cocoliztli. It caused very high fevers. Many people became very ill.

It was a very hard time for them. Some think a lack of rain helped. Dry weather can make people sick. Others think tiny germs caused it. We still study this today. It helps us learn about the past.

In the 1500s, a mysterious sickness hit Mexico.

The Aztec people called it cocoliztli. It was a very bad illness. It caused high fevers and bleeding. Many people died from it. Some say five to 15 million people died. This was a very sad time.

Scientists are still trying to find the cause. Some think a virus caused it. They think rats or mice carried the germ. Others think it was a type of bacteria. In 2018, experts studied old teeth. They found a germ called Salmonella. This germ can cause fever.

Other things made the sickness worse. There were very long droughts. A drought is a time with no rain. The dry weather made life hard. Also, many people lived close together. This helped the sickness spread fast. The sickness mostly hurt the native people. It did not hit Europeans as hard. We still study cocoliztli today to learn more.

In the 1500s, a mysterious illness hit the land of New Spain.

The Aztec people called this sickness cocoliztli. This word means pestilence in their language. It was a very serious disease that caused high fevers and bleeding. It hit the Mexican highlands very hard. Many millions of people died from these outbreaks. Some experts say five to 15 million people passed away. This makes it one of the worst epidemics in Mexico's history.

Doctors and scientists are still working to understand how it worked. The sickness moved very quickly through the body. A person could die in just a few days.

Symptoms included severe headaches and dark urine. People also suffered from bleeding from the eyes and nose. Some even had dark tongues or skin spots. Because the disease worked so fast, it left few marks on bones. This makes it hard for researchers to find clues in old skeletons.

History shows that these outbreaks happened many times. There were at least 12 different cocoliztli epidemics. The biggest ones happened in 1545, 1576, 1736, and 1813. One famous person affected was Bernardino de Sahagún. He was a Spanish author who wrote the Florentine Codex. He got sick in 1546 and again in 1590. He eventually died from the disease. These dates help us see how the sickness lasted for a long time.

Many things helped the sickness spread during that era. First, there were huge droughts with almost no rain. These droughts lasted for many years in the region.

Second, many people were forced to live in crowded groups. This brought people and animals much closer together. New animals from Europe also arrived during this time. Some scientists think rats and mice carried viruses during the rainy seasons. These factors made it very hard for people to stay healthy.

Researchers have found new clues about the cause lately. In 2018, a team studied 29 old teeth from Oaxaca.

They found DNA from a bacteria called Salmonella. Specifically, it was a type called Paratyphi C. This bacteria causes enteric fevers in humans today. Other experts still think a virus might be the cause. They believe the sickness might have come from New World rodents. We are still learning more about this amazing and sad history.

The Cocoliztli epidemics were a series of devastating outbreaks in 16th-century New Spain.

The Aztec people used the Nahuatl word "cocoliztli" to describe this pestilence. These outbreaks primarily targeted the Mexican highlands. They caused massive demographic collapses among Indigenous populations. Some estimates suggest between 5 and 15 million people died. This makes it one of the most severe epidemics in Mexican history.

The disease was defined by its extreme virulence. This means it was very strong and spread quickly. Victims experienced a rapid onset of symptoms without warning. They suffered from high fevers and severe headaches. Other symptoms included vertigo and dark urine. Many people also experienced profuse bleeding from the nose, eyes, and mouth. In some cases, patients suffered from gastrointestinal hemorrhaging and bloody diarrhea. Death often occurred within just three to seven days after the first symptoms appeared.

Researchers face challenges when studying this disease in the archaeological record. Because cocoliztli killed so quickly, it often left no lesions on bones. Most bone-marking diseases leave physical traces on the skeleton. Cocoliztli primarily damaged the respiratory and gastrointestinal systems. This makes it difficult for scientists to identify the pathogen through skeletal remains alone. However, modern technology is helping to solve these mysteries.

History records at least 12 different cocoliztli epidemics. The most massive outbreaks occurred in 1545, 1576, 1736, and 1813.

The 1545 outbreak was particularly catastrophic. During this era, the Spanish clergyman Bernardino de Sahagún was affected. He was the author of the Florentine Codex. Sahagún contracted the disease in 1546 and again in 1590. He eventually died from the illness.

Several environmental and social factors likely fueled these outbreaks. Following the Spanish conquest in 1519, Indigenous peoples were moved into “reducciones”. These were crowded settlements designed for easier governance and religious conversion. Such density increased the contact between people and animals. Many animals brought from the Old World acted as disease vectors. Furthermore, the region suffered through massive megadroughts. One drought stretched from Venezuela all the way to Canada. These droughts may have worsened sanitation and hygiene. Some scientists believe the rains following these droughts increased populations of rodents. These rats and mice might have carried arenaviruses. An arenavirus is a type of virus that can cause hemorrhagic fevers.

There is significant debate regarding the exact biological cause. For a long time, many believed it was a viral hemorrhagic fever. This theory suggests a New World virus was responsible. However, in 2018, new DNA evidence emerged from the Oaxaca region.

Scientists examined the teeth of 29 individuals from a 16th-century cemetery. They used a tool called MALT to match DNA fragments. They discovered the presence of Salmonella enterica serovar Paratyphi C. This bacterium causes enteric fevers, also known as paratyphoid. This specific strain is unique to humans.

Even with this discovery, the scientific community remains divided. Some researchers, like evolutionary geneticist María Ávila-Arcos, question the Salmonella theory. They note that the symptoms of Paratyphi C do not perfectly match the historical descriptions. For example, current infections do not typically cause the severe gastrointestinal hemorrhaging seen in the 1500s. Others believe that RNA viruses have not been sufficiently investigated. The complexity of the history suggests that different outbreaks may have had different causes. The study of cocoliztli continues to bridge the gap between history, biology, and climate science.