Na­tive rats may have caused Mex­i­can epi­demics blamed on Spa­niards

The Washington Times Weekly - - World - By Mark Steven­son

MEX­ICO CITY — Mex­i­cans have long been taught to blame dis­eases brought by Spa­niards for wiping out most of their In­dian an­ces­tors, but re­search sug­gests things may not be so sim­ple.

Al­though the ini­tial big die-offs are still blamed on the Con­quis­ta­dors who started ar­riv­ing in 1519, even more vir­u­lent epi­demics in 1545 and 1576 may have been caused by a na­tive blood-hem­or­rhag­ing fever spread by rats, Mex­i­can re­searchers say.

The idea has sparked heated de­bate in Mex­i­can aca­demic cir­cles.

One camp holds that the epi­demics could have been spread by rats mi­grat­ing dur­ing a drought cy­cle; oth­ers say newly ar­rived Span­ish­min­ers­may­havedis­turbed the habi­tat of virus-car­ry­ing ro­dents while search­ing for gold and sil­ver.

The re­vi­sion­ists draw sup­port from one of the only au­thor­i­ta­tive first­hand ac­counts of the epi­demics — a text lost for hun­dreds of years un­til it was found, mis­filed, in a Span­ish ar­chive.

Fran­cisco Her­nan­dez, a physi­cian to the Span­ish king who wit­nessed the epi­demic of 1576 and con­ducted au­top­sies, de­scribed a fever that caused heavy bleed­ing, sim­i­lar to the hem­or­rhagic Ebola virus. It raced through the In­dian pop­u­la­tion, killing four out of five peo­ple in­fected, of­ten within a day or two.

The World Health Or­ga­ni­za­tion says the Ebola virus was first med­i­cally iden­ti­fied in Africa in 1976 af­ter epi­demics in north­ern Zaire, now the Demo­cratic Repub­lic of the Congo, and south­ern Su­dan. It is one of the most vir­u­lent hu­man vi­ral dis­eases, caus­ing death in 50 per­cent to 90 per­cent of cases. Sev­eral vari­ants of Ebola virus have been iden­ti­fied.

“Blood flowed from the ears and in many cases blood truly gushed from the nose,” Fran­cisco Her­nan­dez wrote of the 1576 out­break in Mex­ico. “Of those with re­cur­ring dis­ease, al­most none was saved.”

Dr. Rodolfo Acuna-Soto, a Har­vard-trained epi­demi­ol­o­gist who teaches mi­cro­bi­ol­ogy at Mex­ico’s Na­tional Au­ton­o­mous Univer­sity, had Dr. Her­nan­dez’s work trans­lated from the orig­i­nal Latin in 2000. He fol­lowed up with re­search into out­breaks in Mex­ico’s iso­lated cen­tral high­lands, where in­dige­nous rats may have spread the dis­ease through urine and drop­pings.

Dr. Acuna-Soto’s the­ory — which has been pub­lished in sev­eral sci­en­tific jour­nals, in­clud­ing Emerg­ing In­fec­tious Dis­eases and the Amer­i­can Jour­nal of Trop­i­cal Medicine and Hy­giene — runs counter to re­ports that most of Mex­ico’s In­dian pop­u­la­tion died of Span­ish-im­ported dis­eases such as small­pox, to which their bod­ies had no im­mu­nity.

“This wasn’t small­pox,” said Dr. Acuna-Soto. “The pathol­ogy just does not fit.”

He said some his­to­ri­ans in Mex­ico are of­fended by his the­ory.

“Much of the rea­son why th­ese epi­demics were left un­stud­ied was that it was po­lit­i­cally and in­sti­tu­tion­ally eas­ier to blame the Spa­niards for all of the hor­ri­ble things that might have hap­pened,” he said. “It was ‘the of­fi­cial ver­sion’ of his­tory.”

Im­ported dis­eases such as small­pox, measles and ty­phoid fever cer­tainly caused huge num­bers of deaths, start­ing in 1521. But the epi- demics of 1545 and 1576 struck sur­vivors of the first die-offs and their chil­dren, who prob­a­bly would have de­vel­oped some im­mu­nity.

Al­though no re­li­able fig­ure is avail­able on Mex­ico’s pop­u­la­tion in the 1500s, es­ti­mates range from 6 mil­lion to 25 mil­lion.

The epi­demic “was so big that it ru­ined and de­stroyed al­most the en­tire land,” wrote Fray Juan de Torque­mada, a Fran­cis­can his­to­rian who wit­nessed the epi­demic of 1576. He added that Mex­ico “was left al­most empty.”

“Many were dead and oth­ers al­most dead, and no­body had the health or strength to help the dis­eased or bury the dead.”

Other ac­counts men­tion a ro­dent in­va­sion, and Dr. Acuna-Soto joined re­searchers from the United States to in­ves­ti­gate whether an ab­nor­mally se­vere drought might have pushed rats into hu­man set­tle­ments or vice versa.

An­other Mex­i­can spe­cial­ist in­sists that the ro­dents men­tioned in texts from the era prob­a­bly came from Europe or Asia, car­ry­ing the bubonic plague, which some­times caused its vic­tims to vomit blood.

Elsa Malvido, a de­mog­ra­pher, his­to­rian and spe­cial­ist in an­cient epi­demics at the Na­tional In­sti­tute of An­thro­pol­ogy and His­tory, said the plague could have caused the more se­vere hem­or­rhagic symp­toms recorded by Dr. Her­nan­dez, be­cause it was at­tack­ing a pop­u­la­tion with no im­mu­nity what­so­ever.

Dr. Car­los Vi­esca, di­rec­tor of med­i­cal his­tory at the Na­tional Au­ton­o­mous Univer­sity of Mex­ico, said he is close to be­ing con­vinced that the epi­demics were na­tive.

“The prob­lem didn’t start in Aca­pulco or Ver­acruz,” the two main sea­ports where rats would have landed from over­seas, he said. In­stead, the dis­ease ap­pears to have started in the cen­tral high­lands at a time when the Spa­niards sent min­ing ex­pe­di­tions to un­set­tled parts of Mex­ico, sug­gest­ing that hu­mansin­vad­e­dro­den­thabi­tats,he said.

Rel­a­tively few Spa­niards were af­fected by the out­break, per­haps be­cause they were pro­tected in ei­ther even­tu­al­ity: If the cause was bubonic plague or small­pox, their bod­ies had greater im­mu­nity to it; and if it was ro­dent-borne, they were less likely to come into con­tact with the an­i­mals.

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