US/UK – There are four types of plasmodium that transmit malaria to humans: the vivax, the malariae, ovale and falciparum (the latter is the most lethal and prevalent in Africa), and among the four, each year causes 400 million cases of malaria worldwide.

The most widespread and best adapted to the circumstances over the centuries is plasmodium vivax, according to two studies published this week in Nature Genetics, which is the largest research effort to date.

These studies revealed a little more about this disease, its origin and dissemination worldwide, but especially help to know how this parasite is adapting to changes and is resistant to current drugs.

The first work, funded by the National Institute of Allergy and Infectious Diseases (NIAID) of the US, has sequenced the complete genome of almost 195 strains of plasmodium vivax in Latin America and Asia.

 The second, led by researcher Dominic Kwiatkowski, of the Wellcome Trust Sanger Institute (Hinxton, UK), analyzed the genome of other strains of plasmodium vivax 200, Asia and Pacific.

NIAID Director Anthony S. Fauci said that historically, Plasmodium vivax has remained in the background, behind the more deadly plasmodium falciparum, but this strain is a great burden to public health in many countries.

Plasmodium vivax is the most widespread in the world, with a presence in Latin America, part of Africa and Asia and Pacific. Thanks to the large amount of genomic information provided by these studies, the first conclusion to be drawn is the great genetic diversity of this parasite, which is much more diverse than falciparum, according to researcher Ivo Mueller from ISGlobal and study co-author.

Probably, this genetic diversity serves human along migration history, and how the parasite was distributed throughout the world. Thus, the study finds that the parasites in Latin America are very different from those of Asia, Madagascar and India and probably “very close” to those who were in Spain and Portugal in the sixteenth century, when there was still a lot of malaria in Europe and came to the new continent with European conquerors. Mueller believes that parasites in Latin America are the descendants of Europeans, and that’s why they are so different from those in Asia.

The study, published in Nature Genetics, also finds that parasites Madagascar and India are very diverse. However, within Asia, the great movement of peoples in the past 5,000 years has made this continent parasites are more alike, while places like Papua New Guinea, in the Pacific, are very different strains of from Asia.