Barbara Burleigh

Barbara Burleigh, an assistant professor in the Department of Immunology and Infectious Diseases, is one of nine scientists to be selected for a 2002 Investigators in Pathogenesis of Infectious Disease Award from the Burroughs Wellcome Fund. Burleigh will use the $400,000, five-year award to continue studying Chagas disease, a leading cause of heart failure in Latin American countries. She was the only parasitologist selected this year for the award.

"The Fund’s selection was based on the scientific excellence and innovation of the proposal, the strength of the scholarly environment at the institution and the accomplishments of Barbara as an independent researcher," wrote Bernadette Marriott, vice president of programs and communications at the Burroughs Wellcome Fund, in a letter to Dean Barry Bloom.

Chagas disease is caused by a parasite called Trypanosoma cruzi. The parasite is carried by biting insects that deposit Trypanosoma cruzi onto the skin of humans through the insects’ feces. The parasite enters the bloodstream and infects different muscles but does the most damage to the heart, where it burrows into the cells of the cardiac tissue.

"Once it’s there, you can’t get rid of it," said Burleigh. "We’re interested in determining how the parasite establishes itself in cells."

Trypanosoma cruzi invading a cell

"But for some reason, muscle, and particularly the heart, are privileged areas for the parasite," she said. "The parasite can persist there for decades."

After the initial phase of infection, the disease enters a stage that can last for years without symptoms. Then, for unknown reasons, approximately 30 percent of people infected with the parasite will have their infection convert into full-blown disease. Their hearts enlarge with inflammation. Eventually, their hearts fail.

There are no vaccines to prevent Chagas disease or pharmaceuticals to treat the chronic disease.

Trypanosoma cruzi infects approximately 20 million people in Latin America, said Burleigh. Although the parasite is endemic in Latin America, Trypanosoma cruzi is causing concern in the US because of the potential for immigrants carrying the parasite to donate blood or organs for transplantation, said Burleigh. The US blood supply currently is not screened for Trypanosoma cruzi.

Burleigh is using model cells from rats to study very early events when the parasite infects cells. How does the parasite get past the cell’s barriers? Once inside, what does it do to the host cell?

Using genomics technologies, Burleigh has already made an interesting observation. Trypanosoma cruzi represses a cellular pathway that leads to fibrosis, a process that builds up connective tissues and causes scars to form. She is now investigating how and why the parasite can affect the fibrogenic process, which could have far-reaching therapeutic benefits for treating fibrosis, she said.

Chagas disease was first described in 1909. After people started moving from rural areas to cities in the 1970s and 1980s, it became an urban disease, further fed by contaminated blood transfusion supplies, according to the World Health Organization. Interventions have helped infection rates decline in some areas of Latin America.

The Burroughs Wellcome Fund is a private, independent non-profit foundation in the Research Triangle Park, NC.