Plasmodium Vivax - Taxonomy

Taxonomy

P. vivax can be divided into two clades one that appears to have origins in the Old World and a second that originated in the New World. The distinction can be made on the basis of the structure of the A and S forms of the rRNA. A rearrangement of these genes appears to have occurred in the New World strains. It appears that a gene conversion occurred in an Old World strain and this strain gave rise to the New World strains. The timing of this event has yet to be established.

At present both types of P. vivax circulate in the Americas. The monkey parasite - Plasmodium simium - is related to the Old World strains rather than to the New World strains.

A specific name - Plasmodium collinsi - has been proposed for the New World strains but this suggestion has not been accepted to date.