Invention: Genetically-modified mosquitoes to control dengue fever
Dengue fever is an excruciatingly painful – and sometimes fatal – disease that affects millions of people each year. The culprit behind its spread is a mosquito that has proven tricky to keep in check. That is until now. British scientist Luke Alphey has come up with a way to use the mosquito as a tool to control its own species. By programming an extra gene into the mosquitos’ DNA, he has ensured that the resulting mosquito larvae never reach reproductive maturity.
For more than ten years, Alphey has been supercharging a decades-old method known as the “Sterile Insect Technique” (SIT) to turn mosquitoes’ natural reproductive instincts against them. Through research Alphey conducted at Oxford University along with fellow scientist Dean Thomas and later at their university spin-off company, Oxitec, Alphey developed a method to use genetic engineering to ‘sterilise’ maleAedes aegypti mosquitos so that when released, these modified mosquitos breed offspring that do not survive to adulthood.
With successive releases, the invasive mosquito population is reduced, leading to fewer biting mosquitos and lower risk of disease transmission. This ingenious technique can reduce mosquito numbers by more than 90% in target populations – far better than current methods – offering viable mosquito control that does not rely on toxic pesticides.
Societal benefit
After malaria, dengue fever is the second-most widespread mosquito-borne disease in the world. The World Health Organization (WHO) estimates that every year, between 50 and 100 million people suffer, and about 25,000 die, from the disease. Worse still, the rate of new infections is rising. Since the 1970s, the number of countries affected by dengue outbreaks has risen tenfold, making dengue the fastest growing mosquito-borne disease in the world.
One of the biggest problems facing public health officials is that there is currently no cure for dengue, nor any way to protect a population from getting sick in the first place. An effective vaccine has so far proven elusive because dengue is caused by four different types of the virus. In fact, when someone becomes infected with one strain of the virus, they actually increase the risk of developing a more severe form of the illness if they are infected with another strain later in life.
Economic benefit
According to WHO, as much as 40% of the world’s population – or 2.5 billion people – are at risk of contracting dengue. The economic burden of the disease has been estimated to be around € 1.72 billion (US$ 2.1 billion) per year in the Americas alone. Oxitec has the support of the Biotechnology and Biological Sciences Research Council (BBSRC), the largest funder of non-medical bioscience in the UK, as well as the Bill and Melinda Gates Foundation. In June 2014, a € 7.7 million (£ 6.1 million) investment round was completed and the technology is now on the brink of commercialisation In what may likely be the largest test of sterilized mosquitoes to date, The Florida Keys Mosquito Control Department (FKMCD) has requested approval from the US Food and Drug Administration for a test release in 2015.
