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The most complete genome of the parasite that causes Chagas disease

Uruguayan scientists obtain the most complete genome of the parasite that causes Chagas disease

The most accurate and complete genome so far of Trypanosoma cruzi, the parasite that causes Chagas’ disease, has been recently made available in an article published in Microbial Genomics (April 30). The paper is a result of a collaborative work made by scientists from the Institut Pasteur de Montevideo (IP Montevideo), the Faculty of Sciences and Faculty of Medicine of the University of the Republic (Uruguay).

The new genetic information will improve our knowledge of this disease —which affects approximately six million people in Latin America— allowing researchers to have more detailed information of the biology of the microorganism, how it spreads in the human body and its strategies to avoid the immune system, said Dr. Luisa Berná, researcher of the Molecular Biology Unit (UBM) of IP Montevideo and first author of the article.

The project is a joint collaboration between scientists from the UBM at the IP Montevideo —coordinated by Dr. Carlos Robello—, and Dr. Fernando Alvarez-Valin group from Biomathematics Section of the Faculty of Sciences.

To sequence the genome they used a third generation sequencing technology that allows them to decode the genome architecture and regions that were previously unknown so far due to the complexity of this organism. Third generation technologies have recently been used to solve complex genomes by leading research centres. This is the first time that Uruguayan research team have used PacBio’s technology providing a higher performance compared to previous instruments.

This new technology facilitates the assembly of the complete sequence of two genomes of T. cruzi, including complex regions that could not be identified nor located in previous attempts using other technologies due to their complexity. It also showed the existence of a peculiar organization of genes in two compartments. The results are available on a friendly web platform (http://bioinformatica.fcien.edu.uy/cruzi).

Although the first genome of T. cruzi was sequenced in 2005, this much more precise version will allow high-impact experiments to be carried out, such as the elimination of genes or “knock-outs”, which have a fundamental role in the search for drugs against this parasite.

This new “writing” of the genome of T. cruzi is, so far, the newest reference for scientists who have studied Chagas disease, an illness that remains complex and unattended after more than one hundred years after its description.

 

Chagas disease

Chagas disease is a neglected illness endemic in 21 countries of the Americas. According to the Pan American Health Organization, there are 30,000 new cases each year in the region, 14,000 deaths and 9,000 new-borns infected during pregnancy. It is mainly transmitted by Triatominae insects, which usually live in poorly built or precarious households. They hide during the day and become active at night, when they bite.

Around 70 million people in the Americas live in exposure areas and are at risk of contracting this disease. However, Chagas is almost 100% curable if it is treated during early stages with Benznidazole or Nifurtimox, the only two drugs with proven efficacy but with severe side effects.