A team of international scientists has sequenced the genomes of three species of parasites responsible for causing diseases that kill or cripple millions, primarily in tropical and sub-tropical countries.
Howard Hughes Medical Institute (HHMI) scientists who participated in the project say the sequencing of the genomes of the parasitic protozoa that cause Chagas disease, African sleeping sickness, and leishmaniasis, could significantly impact world health. Some of the genes discovered may prove to be good drug and vaccine targets.
The research is published in a special issue of the journal Science focusing on the genome sequences of Trypanosoma brucei, Trypanosoma cruzi, and Leishmania major and the public health threat that these parasites represent. One of the studies' key findings is the identification of gene sequences that are involved in the host-parasite relationship and in the regulation of the parasite metabolism.
Shulamit Michaeli, a HHMI international research scholar at Bar-Ilan University in Israel and co-author on the L. major paper, is optimistic about the impact of the work on drug development. "By providing information on virulence factors, critical enzymes in key metabolic pathways, and potential vaccine candidates, this study will advance tropical medicine by helping us develop new drugs against these diseases," she said.
Alberto Frasch, a HHMI international scholar from Argentina, agrees. "Having a sequenced genome should aid us immeasurably in finding new drugs," said Frasch, who is director of the Institute for Research in Biotechnology of the National University of General San Martin in Buenos Aires and an author on the T. cruzi and L. major papers. Frasch explained that the drugs currently available to treat diseases caused by trypansomes "either have toxic side effects or lack efficiency in some stages of infection, as in chronic Chagas disease." "Also," he said, "drug resistance in diseases caused by trypanosomatids complicates their treatment. The information obtained from genome analysis might help us understand the resistance mechanisms to drugs now used."
Trypanosomes are a type of single-celled microorganism that has developed elaborate schemes to evade the immune systems of their hosts. They are spread to humans through contact with infected animals. Trypanosoma cruzi causes Chagas disease, a devastating public health problem in Cental and South America and Mexico, while Trypanosoma brucei causes African sleeping sickness, and Leishmania major causes leishmaniasis.