How Malaria Was Spread in South America?

By  Multiple News    

GroundReport - Scientists have long debated how and where it originated malaria infection caused by a parasite transmitted by the bite of a mosquito.

Now an international team of scientists seems to have found the answer.

Genetic analysis of the parasite Plasmodium falciparum revealed that he came to South America, relatively recently, from Africa to the transatlantic slave trade.

Malaria, a disease that affects 500 million people each year, is endemic in many regions of the world but until now it was unclear how the parasite spread.

There are five known species of this organism are known to infect humans, but P. falciparum, which is widespread in tropical and subtropical regions is the most lethal, causing the deaths of more than one million people each year.

Although it has been thought that the P. falciparum originated in Africa, no one knew how they were the routes of spread to other regions.
For example, one theory is that it expanded into Asia some 6,000 years ago with the emergence of agricultural societies, which increased mosquito populations.

But other theories state that the P. falciparum spread 60,000 years ago along with the populations of Homo sapiens who emigrated from Africa. 

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As to how the disease came to South America, the assumptions mentioned both European settlers and the African slave trade, but the evidence so far not been conclusive.

The research, coordinated by Professor Francisco Ayala of the University of California, Irvine, collected samples of human blood infected with P. falciparum in 24 regions of the world including Africa, Middle East, Southeast Asia and South America.

DNA analysis of the samples showed that the populations of the parasite in South America were subdivided into two major genetic groups: the north, to inlcuía peoples of Colombia, and southern populations of French Guyana, Brazil and Bolivia.

Subsequent testing of genetic linkage of these two groups with African falciparum showed that both were introduced independently during the transatlantic slave trade.

This means that the disease reached the continent between the ages 16 and 19, much more recently than had been thought until now.

"Some people argue that the disease has existed in the region for thousands of years," says Professor Ayala.

"What is clearly shown that malignant malaria has been in America for only about 300 or 500 years," he adds.

According to the scientist, the finding also of historical interest may have "important implications for health."

"The findings reveal the important influence of human migration in the genetic diversity of P. falciparum."

"And it could explain the emergence of drug resistant malaria," he adds.