University of Glasgow scientists, along with researchers from the Wellcome Trust Sanger Institute by Cambridge, have finally solved and identified the mystery of how malaria is passed and what must be produced from a parasite to transmit the disease from human to mosquito to human. This now opens up an avenue for new drug treatments that could prevent the transmission of the disease.
Malaria had pretty much been eliminated in the 1950s. Nevertheless, today there is an on going risk for malaria to spread again. The World Health Organization 2013 report found that 3.4 billion people in 97 countries and territories worldwide are at risk of getting malaria – the number is half of the world’s population. In 2012, an estimated 483,000 infants under the age of five died from the disease. Almost 90 percent of the deaths occurred in sub-Sahara Africa.
Malaria is passed on to people through mosquito bites, the insects themselves are infected by parasites known as Plasmodium. These parasites come from a previous mosquito blood meal. The final stage called transmission occurs two weeks later when the mosquito feeds again – its saliva mixes with the parasites already in its body and are then passed onto the soon to be infected individual.
Through the transmission stage, the team of Wellcome Trust Sanger Institute and University of Glasgow has identified how the parasite that causes malaria is able to turn itself on and transmit itself.
How this occurs is through what is known as a single regulatory protein acting as what they call the “master switch,” which leads to the development of the sexual forms of both female and male parasites, also known as gametocytes. These very cells are what is now known to infect the mosquito and initiate the transmission stage.
However, if the parasite can not undertake the important sexual development, the disease can not be transmitted between hosts. The mystery of how parasites produce sexual stages and the key behind the transmission of malaria has finally been solved after years of research from malaria researchers.
The research occurred over a three year period. Scientists used techniques that involved complicated genome sequencing to the protein that prevents gametocytes from developing. The process was reversed through genetic engineering of the parasites’ gene to repair its switch, therefore restoring the ability of the parasite to make gametocytes. Basically, researchers switched off and then switched on again the process of developing the parasite that transmits the disease from one person to another person – putting the main focus on the protein as the switch.
The findings and how the protein functions means the “transmission switch” could now be turned off through new drug treatments. Researchers calls any new treatment that comes out of the research as an “altruistic intervention;” it would be tested by adults already infected by the disease, but had grown a resistance to it. The drug would then block the switch from turning on, thus preventing the patients from getting infected again, or moreso, from their children or anyone else to get infected. Researchers expect there would be many parents who would agree to accept such treatment, as the greater good of their children and how they’re protected hangs in the balance.
A Wellcome Trust Centre and University of Glasgow professor and director in Molecular Parasitology, Andy Waters, says current drugs no longer have the same effectiveness because of the adaptation and resistance of the parasite. As a result, there is also no vaccine. However, now that the mystery has finally been solved of how malaria passes, new treatments will now arise that can help battle the disease.
By Kollin Lore