Måske er det ikke pænt sådan at rejse rundt og kolonisere andre blot fordi man tror at de har en masse guld. Men, men, men. Hernan Cortes og hans myrmidonere var måske alligevel ikke de ufrivilligt massemordere i deres griske forehavende. Fra Discover Magazine
The fevers were contagious, burning, and continuous, all of them pestilential, in most part lethal. The tongue was dry and black. Enormous thirst. Urine of the colors of sea-green, vegetal green, and black, sometimes passing from the greenish color to the pale. Pulse was frequent, fast, small, and weak—sometimes even null. The eyes and the whole body were yellow. This stage was followed by delirium and seizures. Then, hard and painful nodules appeared behind one or both ears along with heartache, chest pain, abdominal pain, tremor, great anxiety, and dysentery. The blood that flowed when cutting a vein had a green color or was very pale, dry, and without serosity. . . . Blood flowed from the ears and in many cases blood truly gushed from the nose. . . . This epidemic attacked mainly young people and seldom the elder ones.
“This was certainly not smallpox,” Acuña-Soto says. “If they described something real, then it appeared to be a hemorrhagic fever.”
Hemorrhagic fevers are viral diseases with names that evoke justifiable dread—Ebola, Marburg, Lassa. They strike with sudden intensity, rarely respond to treatment, kill at high rates, then vanish as mysteriously as they came. They are called hemorrhagic because victims bleed, hemorrhaging in their capillaries, beneath the skin, often from the mouth, nose, and ears. The bleeding doesn’t kill, but the breakdown of the nervous system does. At first there is fever, fatigue, and dizziness, but within a few days the person falls into delirium and finally a coma.
All types of hemorrhagic viruses share traits. They are extremely simple, composed only of RNA enveloped in a fatty membrane, and they all must develop first in an animal host—often rodents or bats—and are spread by insects such as ticks or mosquitoes. A bite, direct exposure to rodent feces or urine, or indirect exposure through windblown particles can pass the virus to humans.
If cocolitzli had been caused by a hemorrhagic virus, Acuña-Soto realized, the Spanish could not have brought it with them. Such diseases do not readily pass from one person to another, so the virus must have been native.
Acuña-Soto saw that each of the cocolitzli epidemics appeared to be preceded by several years of drought. He also found that the epidemics didn’t happen during the drought. They appeared only in the wet periods that followed. That was the crucial clue he had missed: It was raining when people got sick.
The clue offered Acuña-Soto a hypothesis—but only if he was correct that outbreaks of disease always followed periods of drought. The codices wouldn’t stand up as scientific evidence. For instance, two periods might be called droughts, but their severity might be very different. If he claimed that a native hemorrhagic virus, not an outbreak of Old World smallpox, had killed 10 million Aztecs, he needed better data, some way to measure the exact intensity and extent of the droughts and rains.
The evidence from the Douglas firs shows that during the 16th century central Mexico not only lacked rain but also suffered the most severe and sustained drought in 500 years, one that encompassed nearly the entire continent. Moreover—here was Acuña-Soto’s smoking gun—the tree-ring records show wet interludes setting in around the years 1545 and 1576, the years of the cocolitzli.
With the climate data in place, Acuña-Soto could piece together a convincing explanation of those epidemic years. Cocolitzli had been caused by a hemorrhagic fever virus that had lain dormant in its animal hosts, most likely rodents. Severe drought would have contained the population of rodents, forcing them to hole up wherever they could find water. Initially, only a small percentage may have been infected, but when forced into close quarters the virus was transmitted during bloody fights. Infected mother rodents then passed the virus to their young during pregnancy. When the rains returned, the rodents bred quickly and spread the virus—through their urine and feces—as they came into contact with humans in fields and homes. Once infected, humans transmitted the virus to one another through contact with blood, sweat, and saliva.
Acuña-Soto’s trips into the woods with Stahle and the Mexican researchers continue to fill in epidemiological details. “I have evidence from 24 epidemics from 1545 to 1813,” he says. “I am comparing the tree-ring data with each of them.” In each case, he sees the same pattern. He also thinks he may have solved one of the other great mysteries of cocolitzli—namely, why it hit the Aztecs hard but left the Spanish largely unaffected.
Hemorrhagic viruses affect human populations that are already stressed, Acuña-Soto says. “The natives were poor and probably near starvation and living in unsanitary conditions where the rats would congregate. They also worked in the fields, where they’d be exposed to the rat droppings. The Spanish made up the upper classes.”
Da jeg er lidt optaget af vejret for tiden vil jeg lige påpege at Aztekerne altså døde af følgerne af den enorme klimaforstyrrelse (Climate Disruption), som fulgte med den lille istid efter at have styret for vildt under den behagelige middelalders varmeperiode. Så sæt slæden i tomgang, mens de får dem en kop kaffe. Så gør de deres for at forebygge en gentagelse af en sådan klimakatastrofe.