Vivax Malaria May Be Evolving Around Natural Defense

http://www.sciencedaily.com/releases/2013/11/131115094906.htm

Nov. 15, 2013 — Researchers at Case Western Reserve University and Cleveland Clinic Lerner Research Institute have discovered recent genetic mutations in a parasite that causes over 100 million cases of malaria annually -- changes that may render tens of millions of Africans who had been considered resistant, susceptible to infection.

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Researchers have long thought that P. vivax infects a person one way: a protein on the parasite, called the Duffy binding protein, latches onto a Duffy receptor on the surface of the person's red blood cell and works itself through the membrane. People who lack the receptor are called Duffy negative and are resistant to infection.

But, during the last decade, reports of cases of Duffy negative patients with P. vivax infections have been on the rise in several parts of the world.

P. vivax has been called benign malaria because it is less lethal than malaria caused by Plasmodium falciparum. But unlike its cousin, P. vivax can hide from treatment in a host's liver and repeatedly emerge to cause relapses of debilitating headaches, nausea and fever. This chronic malaria often triggers a cycle of poverty for sufferers left unable to work for long periods. By weakening the immune system, the disease contributes to death.

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