In 1545 a deadliest epidemics outbreak in Mexico’s Aztec nation and killed almost 80% people. Victim started coming down with high fevers, headaches and bleeding from the eyes, mouth and nose. Death generally followed in three or four days.
On Monday scientists swept aside smallpox, measles, mumps, and influenza as likely suspects, identifying a typhoid-like “enteric fever” for which they found DNA evidence on the teeth of long-dead victims.
The outbreak is considered one of the deadliest epidemics in human history, approaching the Black Death bubonic plague that killed 25 million people in western Europe in the 14th century – about half the regional population.
Within five years as many as 15 million people, an estimated 80% of the population – were wiped out in an epidemic the locals named “cocoliztli”. The word means pestilence in the Aztec Nahuatl language. Its cause, however, has been in questioned for nearly 500 years.
A second outbreak from 1576 to 1578 killed half the remaining population. “In the cities and large towns, big ditches were dug, and from morning to sunset the priests did nothing else but carry the dead bodies and throw them into the ditches,” is how Franciscan historian Fray Juan de Torquemada is cited as chronicling the period.
Scientists now say they have probably unmasked the culprit. Analysing DNA extracted from 29 skeletons buried in a cocoliztli cemetery, they found traces of the salmonella enterica bacterium, of the Paratyphi C variety.
It is known to cause enteric fever, of which typhoid is an example. The Mexican subtype rarely causes human infection today.
Many salmonella strains spread via infected food or water, and may have travelled to Mexico with domesticated animals brought by the Spanish, the research team said.
“We tested for all bacterial pathogens and DNA viruses for which genomic data is available,” and salmonella enterica was the only germ detected, said co-author Alexander Herbig, also from Tuebingen University.
>Juthy Saha
