A genetic variation that protects people of African descent from a strain of malaria may also increase their risk of HIV infection by 40 percent, The Wall Street Journal reports (wsj.com, 7/16).

According to the article, a five-year study conducted by U.S. and U.K. researchers focused on a gene that encodes for a protein called the Duffy Antigen Receptor for Chemokines, which is found on the surface of red blood cells. Researchers speculate that this Duffy protein can soak up HIV particles and protect cells from infection.

The WSJ adds that people with a variation of this gene—including 90 percent of people in Africa and 60 percent of African Americans—don't carry this protein, increasing their risk for HIV transmission.

“It helps to explain why HIV is so prevalent in Africa,” said study co-author Robin Weiss, a virologist at University College London. “Most Africans have a slight genetic bias to being more susceptible.”