Following the genetic footprints of the virus

HIV/AIDS
A new study traces the first movements of a common strain of the HIV virus, suggesting that the virus likely used Haiti as a stepping stone between its origins in Africa and its eventual dispersal to the United States and worldwide. Researchers, led by Michael Worobey at the University of Arizona, charted the course of a common strain of this virus by collecting HIV sequences from patients from around the globe. Some of these sequences were obtained from some of the earliest known AIDS patients in the early 1980s - many of them of Haitian origin - while others were obtained from patients from 19 countries who presented with the disease more recently. These sequences provided "genetic footprints," for calculating where and when the virus might have migrated. After carefully analyzing these footprints, researchers found that this common strain of the HIV virus almost certainly moved from Africa to Haiti around 1966, where it circulated for several years before it migrating to the United States around 1969. Since the first outbreaks of the virus weren't noted until 1981, the study suggests that the virus had been present in the United States for nearly a decade before it was identified as a potent cause of disease. "The virus may have circulated in the United States for longer than we were aware of," Worobey said.

BOTTOM LINE: The AIDS virus likely arrived in the United States a decade earlier than previously believed, using Haiti as a stepping stone between Africa and the United States.

CAUTIONS: It is important to remember that these migrations occurred before anyone knew of the existence of the virus, so these countries could not have possibly controlled the spread of HIV. "Instead of blaming them," Worobey said, "we should direct our sympathies towards these areas."

WHAT'S NEXT: The group would like to further clarify details about the origin and spread of the strain, hoping that this will provide insight into controlling the future spread of the virus.

WHERE TO FIND IT: The Proceedings of the National Academy of Sciences, Oct. 29.

SUSHRUT JANGI

FERTILITY

Diet and exercise can impact fertility, according to a new study by researchers at the Harvard School of Public Health. They found that women are at a higher risk of infertility from ovulation disorders if they consume more trans fats, animal proteins, or high glycemic carbohydrates and less iron, folic acid, multivitamins, vegetable proteins, or high-fat dairy. To see how overall dietary habits and lifestyle affect infertility, a group of researchers led by Jorge Chavarro followed 17,544 women for eight years. The participants, who were all trying to get pregnant, filled out questionnaires on their dietary intake, physical activity, and body weight and also reported back if they discovered they were infertile because of failure to ovulate. Researchers assigned a score of one to five for every factor, dietary or lifestyle, they were testing - the highest score of five was assigned to that level of the factor previously associated with least infertility risk. They found that women who followed a lifestyle and diet satisfying "desirable" levels for five or more of the tested factors showed 84 percent less infertility risk than women who did not follow the recommendations.

BOTTOM LINE: "Modifications in lifestyle and diet can have a substantial effect on infertility caused by ovulation disorders in women," said Chavarro who is also the study's lead author.

CAUTIONS: This is the first study of its kind, and more studies are needed to confirm these findings.

WHAT'S NEXT: Chavarro's group, which is led by epidemiologist and nutrition researcher Walter Willett, wants to investigate how lifestyle and diet affect infertility in men.

WHERE TO FIND IT: Obstetrics and Gynecology, Nov. 5

SENA DESAI GOPAL