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Populations: Case Studies


Drug smuggling routes

As AIDS spread through Southeast Asia in the 1990s, the military government of Burma claimed that the sex industry in neighboring countries was responsible. “Their whole response was to blame ‘those licentious Thais,’” says epidemiologist Chris Beyrer.

But Beyrer theorized that HIV was also likely to be following drug-smuggling routes out of Burma, which produces 60 percent of the world’s heroin. Using blood samples from addicts in the border regions, Beyrer’s team identified different strains of HIV—subtypes called B, C, E, and B/C. By tracing the spread of those strains, the team proved that Burma was indeed a major source of the epidemic. “It’s very gratifying to use new scientific technology to investigate and document political, social, and economic reality,” says Beyrer. “Who would have thought it could be used to nail a junta?”



Legs and arms grotesquely inflated like balloons are hallmarks of elephantiasis. The disfiguring and debilitating disease, endemic to Africa and Southeast Asia, occurs when filarial worms, transmitted by mosquitoes, block the lymph system. Worldwide, more than 120 million people are infected by these parasites. Immunologist Alan L. Scott believes that the worm’s own genes hold clues for protecting against this infection. Specifically, he focuses on genes that encode the worm’s spit—a complex mixture of 500 different proteins. “We believe the spit releases molecules that manipulate the host’s immune response to promote worm infection,” says Scott. His goal: an elephantiasis vaccine.



Private inventions can be enhanced by public research. Consider the GeneChip, a tool developed by the Affymetrix corporation for comparing RNA samples. Rafael A. Irizarry (right), a biostatistician at the Bloomberg School, worked with colleagues to develop statistical procedures that made GeneChip results more precise. Then they made the software for those procedures freely available to researchers around the world.



Nirbhay Kumar knows malaria all too personally. He contracted the disease in the 1970s while completing his PhD in New Delhi. “I had a temperature that was almost 104 degrees and I was shivering like I was buried in Antarctica,” he recalls. “When the fever went down, I was taking a shower in my own perspiration.” Kumar also knows malaria’s global impact: It infects 300 million to 500 million people and kills 1.5 million to 3 million of them every year. As a biochemist and molecular biologist, he has made this pernicious disease the focus of his work. “I wanted to make some contribution to a problem that affects people on a daily basis,” he says. 

At the Bloomberg School’s Malaria Research Institute, Kumar is developing an “altruistic vaccine”—meaning that rather than protecting whoever gets the shot, it prevents the disease from being transmitted any further. When injected into mice and monkeys, Kumar’s vaccine stimulates the production of antibodies that block the sexual development of malaria-causing Plasmodium parasites, which live in mosquitoes. A mosquito bites a vaccinated animal and sucks up the antibodies, which in turn stop any Plasmodium in its system from reproducing. So when the mosquito bites its next victim, it does not pass on new malaria parasites. The idea is to contain the disease. “In the end,” says Kumar, “when you stop transmission, the disease disappears and everyone benefits.”