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University of Iowa News Release

July 15, 2005

Deadly Parasite Genomes Sequenced By International Team

A major international scientific effort, which included a University of Iowa biochemist, has sequenced the genomes of three related parasites that collectively cause death and illness among millions of people every year, mostly in impoverished third world countries.

The genome sequences and analyses are presented in a special issue of the journal Science, published July 15, and the information is described as a "milestone in the centuries-old fight against poverty."

Trypanosoma brucei, which causes African sleeping sickness, Trypanosoma cruzi, which causes Chagas' disease, and Leishmania major, which causes cutaneous leishmaniasis (skin lesions), are all parasites from the same family, although each pathogen is transmitted by a different insect. Each parasite has a very different life cycle and causes very different disease symptoms. There are no vaccines, and the few available drug treatments for these parasitic diseases often are ineffective and even toxic. Because the pathogens primarily affect the world's poorest people in Africa, Asia and Latin America they also place enormous burdens on already fragile economies, hindering socioeconomic development.

John Donelson, Ph.D., UI professor and head of biochemistry in the UI Roy J. and Lucille A. Carver College of Medicine, and his colleagues have been studying T. brucei, T. cruzi and Leishmania for nearly 20 years. He has been part of the international effort to sequence the parasite genomes since its inception and is an author on two papers appearing in the special issue of Science.

"Our hope in determining the genomic sequences of these terrible pathogens in many developing countries is that the information will lead to the development of vaccines, better drugs and improved ways of combating these human diseases than are currently available," Donelson said.

The genomic sequencing data presented in Science has identified a number of genes that may be potential drug or vaccine targets. In addition, up to half of the genes revealed have no known function. Learning the function of these newly discovered genes might provide research leads for developing new treatments or ways to control the parasites.

University of Iowa Health Care describes the partnership between the UI Roy J. and Lucille A. Carver College of Medicine and UI Hospitals and Clinics and the patient care, medical education and research programs and services they provide. Visit UI Health Care online at

STORY SOURCE: University of Iowa Health Science Relations, 5135 Westlawn, Iowa City, Iowa 52242-1178

CONTACT: Jennifer Brown, (319) 335-9917

PHOTOS/GRAPHICS: A photo of Dr. Donelson is available form Jennifer Brown (