Genetic Weakness Found in T. B. Gambiense

Glasgow University scientists have discovered that the sleeping sickness parasite reproduces asexually. The parasite, Trypanosoma brucei gambiense (T.b gambiense) causes African sleeping sickness, a disease that is transmitted through the bite of an infected tsetse fly. The disease begins with fevers and itchiness, with the afflicted eventually lapsing into a coma (which is how the disease got its name). It is common in rural sub-Saharan Africa, with around 70 million people from 36 countries being at risk.

The parasite was originally an animal parasite but entered the human population within the last 10,000 years. The findings that the parasite reproduces asexually suggest that it will have very little genetic diversity. When a creature sexually reproduces, it randomly recombines their DNA in order to create genetic diversity that leads to desirable alterations of DNA and the ‘survival of the fittest’. However, the T.b gambiense parasite does not have this kind of diversity, as it is rather ‘cloned’ from a single parasitic ancestor, and each new parasite is a copy of a copy.

What this means is that it may be a lot easier to try and cure African sleeping sickness. Developing a long lasting treatment to the disease would become a lot more effective. The lack of genetic diversity means that the parasite is unlikely to evolve a resistance any drugs used to fight the disease.  Similarly, in the long term the parasite will be unable to survive indefinitely without sex and genetic diversity, eventually becoming extinct.

This is great news and a big step forward in fighting the disease. The disease, if untreated, is fatal, and with such a large number of people at risk from it, it is vital that research is put into understanding the parasite and developing a cure. The current treatment of the disease is complex, requiring specifically skilled staff, and many of the people at risk live in rural areas with little access to health services. This is a major breakthrough that will hopefully contribute to the development of a cure.

[Jo Reid]



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