Three Tropical Parasites Genetic Code Unravelled

Scientists have now cracked the genetic makeup three fatal diseases –sleeping sickness, leishmaniasis and Chagas disease that are caused by

Scientists have now cracked the genetic makeup three fatal diseases –sleeping sickness, leishmaniasis and Chagas disease that are caused by Trypanosoma brucei, Leishmania major and Trypanosoma cruzi. The three diseases have mostly been to affect people in tropical countries. It is estimated that they affect about half a billion people worldwide and claim more than 150,000 lives annually.

A study conducted by National Institute of Allergy and Infectious Diseases (NIAID) of National Institutes of Health has been published in Science journal.

“Although relatively unfamiliar in the United States, the collective misery caused by these diseases throughout the world is considerable. Having these genomes in hand will give us many new targets for drug and vaccine development,” Anthony S Fauci, director of NIAID said in an interview.

“One of the biggest surprises to come out of the genome sequencing projects is that these parasites – despite major differences in how they are spread and how they cause disease – nevertheless have a core of 6,200 genes in common,” said Martin John Rogers, of NIAID’s Parasitology and International Programs Branch.

Sanjeev Krishna, of St George’s Hospital in London who was one of the authors of the study said that 60 million Africans are affected by sleeping sickness annually. “Perhaps only one in 20 of these will have the chance to access medical care of even the most rudimentary sort,” he said, adding, “Treating sleeping sickness is like a form of medical Russian Roulette because you don’t know who will be saved or killed by the treatment available” He further added that since the sequencing program is completed the hunt will now be on to concentrate on finding the ‘magic bullet’ medicines that will help eradicate these diseases.

“Among these 6,200 genes that need further characterization, there are a good 40 or 50 that definitely appear not to be shared with any other life form so far sequenced. If we can find a core process that are shared by these parasites, then we would have very promising targets,” said Najib El-Sayed of the Institute for Genomic Research in Rockville, Maryland, one of the authors of the study.

Medindia on Leishmaniasis

Leishmaniasis is a neglected disease and known for centuries, Indian physicians applied the Sanskrit term kala azar (meaning "black fever") to an ancient disease that later was known as visceral leishmaniasis. It is also mentioned in texts of the 15th and 16th centuries during the Spanish colonization. It was also called "valley sickness" or "Andean sickness".Disfigurements of the nose and mouth led to it being called "white leprosy".

In 1901, Leishman identified certain organisms in smears taken from the spleen of a patient who had died from "dum-dum fever". At the time "Dum-dum", a town not far from Calcutta, was considered to be particularly unhealthy.

Leishmaniasis causes-
- weight loss,
- fever,
- anemia,

Trypanosoma brucei - causes sleeping sickness and found in African countries
Trypanosoma cruzi - is associated with neurological disorders and also called Chagas disease and found in central and South America
Leishmania donovani - Causes Kalazar – found in India and can lead to organ failure

All the three can be fatal if not treated