加州大學(xué)的一組研究者近日在《美國國家科學(xué)院院刊》（Proceedings of the National Academy of Sciences）發(fā)表論文稱,，引起瘧疾的瘧原蟲是由16世紀(jì)的非洲奴隸交易被引進(jìn)南美洲的,。
多年來，關(guān)于瘧疾是如何進(jìn)入南美的這一論題一直爭(zhēng)論不休,，有人認(rèn)為瘧疾是在數(shù)千年前由鳥類遷徙而跨國大西洋的,，而該研究團(tuán)隊(duì)的這一發(fā)現(xiàn)有力地駁斥了上述理論。
為研究清楚南美洲瘧原蟲的根源,，該研究小組搜集了南美洲,、中亞、非洲雞東南亞17個(gè)國家的被感染者的血液標(biāo)本,，然后對(duì)每一份標(biāo)本進(jìn)行了DNA分析,，并對(duì)所有標(biāo)本的分析結(jié)果進(jìn)行比對(duì)。隨后,，研究者對(duì)蚊子的代數(shù)進(jìn)行了估計(jì),，來計(jì)算南美最早出現(xiàn)瘧疾的時(shí)間。
為了降低估算的不精確性,，研究者使用蚊子每一代的最長(zhǎng)時(shí)間和最短時(shí)間進(jìn)行計(jì)算,，即每年12代和每年6代。使用每年12代的計(jì)算結(jié)果是,，瘧疾約217至495年前在南美出現(xiàn),；使用每年6代的計(jì)算結(jié)果是,，瘧疾約434至900年前出現(xiàn)在南美。
第一個(gè)出現(xiàn)瘧疾的地方在南美的北部,，如墨西哥,、哥倫比亞等，其估算時(shí)間與西班牙奴隸主到南美進(jìn)行奴隸交易的時(shí)間吻合,，而另外一個(gè)地方在南美南部,，其估算時(shí)間與葡萄牙奴隸主到巴西進(jìn)行奴隸交易的時(shí)間吻合。
因此,，該團(tuán)隊(duì)認(rèn)為瘧疾是隨著歐洲奴隸主到南美進(jìn)行奴隸交易而出現(xiàn)的,，當(dāng)時(shí)這些攜帶有瘧原蟲的非洲奴隸們被販賣到南美從事稀有金屬的開采和甘蔗種植工作。（生物谷bioon.com）
doi:10.1073/pnas.1119058109
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Multiple independent introductions of Plasmodium falciparum in South America
Erhan Yalcindag, Eric Elguero, Céline Arnathau, Patrick Durand, Jean Akiana, Timothy J. Anderson, Agnes Aubouy, François Balloux, Patrick Besnard, Hervé Bogreau, Pierre Carnevale, Umberto D'Alessandro, Didier Fontenille, Dionicia Gamboa, Thibaut Jombart, Jacques Le Mire, Eric Leroy, Amanda Maestre, Mayfong Mayxay, Didier Ménard, Lise Musset, Paul N. Newton, Dieudonné Nkoghé, Oscar Noya, Benjamin Ollomo, Christophe Rogier, Vincent Veron, Albina Wide, Sedigheh Zakeri, Bernard Carme, Eric Legrand, Christine Chevillon, Francisco J. Ayalas,François Renaud , and Franck Prugnolle
The origin of Plasmodium falciparum in South America is controversial. Some studies suggest a recent introduction during the European colonizations and the transatlantic slave trade. Other evidence—archeological and genetic—suggests a much older origin. We collected and analyzed P. falciparum isolates from different regions of the world, encompassing the distribution range of the parasite, including populations from sub-Saharan Africa, the Middle East, Southeast Asia, and South America. Analyses of microsatellite and SNP polymorphisms show that the populations of P. falciparum in South America are subdivided in two main genetic clusters (northern and southern). Phylogenetic analyses, as well as Approximate Bayesian Computation methods suggest independent introductions of the two clusters from African sources. Our estimates of divergence time between the South American populations and their likely sources favor a likely introduction from Africa during the transatlantic slave trade.
