Key Virulence Factors of Human Malaria Parasite Much More Ancient Than Thought; Intact Gene Segments Were Exchanged and Evolved in Plasmodium Sub-Genus in Apes Before Emergence of Human Malaria Parasiste (P. falciparum)

The malaria parasite (Plasmodium falciparum) (image) molecules associated with severe disease and death--those that allow the parasite to escape recognition by the immune system--have been shown to share key gene segments with chimp and gorilla malaria parasites, which are separated by several millions of years of evolution, according to a new study led by researchers at the Harvard T.H. Chan School of Public Health. This new information about the origin and genetics of human malaria virulence factors could aid in basic understanding of the causes of malaria and provide targets for drugs and vaccines. The study was published online on October 12, 2015 in an open-access article in Nature Communications. The article is titled “ "Ape Parasite Origins of Human Malaria Virulence Genes.” "The evolution of these key virulence determinants doesn't occur in the same way as in other pathogens. Instead of gradually changing by mutation, as the flu virus, these malaria parasites exchange intact gene segments, like shuffling a deck of cards," said Caroline Buckee, Ph.D., Assistant Professor of Epidemiology at Harvard’s Chan School and senior author of the study. Malaria kills more than 500,000 people a year, mostly children in Sub-Saharan Africa. Severe disease syndromes in human malaria--including severe malarial anemia, pregnancy-associated malaria, and cerebral malaria--have been linked with the malaria parasite's ability to cause infected red blood cells to bind to the inner lining of blood vessels. This ability of the infected cells to adhere in this way--which is key to malaria's virulence--is linked with certain genes called var genes.
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