Day 47- Re- engineering mosquitos to fight disease.

Hadyn Parry calls the mosquito the world’s most dangerous animal. It has killed more people than any creature in history; more have died from mosquito born illnesses than any war or plague. There are 200-300 million diagnosed cases of malaria with a million and a half deaths from the disease yearly. Fifty years ago, Dengue fever was unheard of; now it is one of the largest threats we have, infecting between 50-100 million people yearly. There are four strains of Dengue; once you develop one, the body produces antibodies to fight it in future. Unfortunately these antibodies make you more susceptible to the other three strains, which can lead to more serious conditions like haemorrhagic fever or shock. Dengue fever is on the rise; at the time of this talk the first cases had been reported in Madeira. According to Parry, where the mosquito is, Dengue will follow.
So why have we not eradicated these diseases or their carrier? There are two ways to kill the mosquito. We can put chemicals into water where they breed; in an urban environment this could be anywhere from a puddle to a potplant. Or we could kill them as they fly, using an unpleasant and largely ineffective chemical filled smoke. The best protection for us remains a long sleeved shirt and some DEET. Any measure to reduce the mosquito population needs to be safe to humans, species specific and environmentally friendly. Parry has been working on such a project in conjunction with Oxford University for over ten years and they believe they’ve found the answer- genetically engineering the male mosquito to render it sterile.
Two key features of mosquito biology are that males don’t bite and they’re good at finding females. A single female can lay 100 eggs at a time and up to 500 in her lifetime. If the male carries a gene that causes the death of an offspring then less offspring will survive. In a small room in Oxford, Parry states they can produce about 20 million modified mosquito eggs weekly, which are divided into male and female eggs before the males are transported in small containers around the world.
Field trials in the Cayman islands, Brazil and Malaysia have been hugely promising. Starting in small villages of about 3000 people, the population of mosquitos was decreased by about 85% in 4 months. They’re now scaling the project up to trial it in towns of about 50,000 people. The Brazilian government have funded their own ‘mosquito factory.’
Genetic engineering is an area shrouded in controversy. It has been used in agriculture, medicine, research and biotechnology, usually to improve productivity. If this project is successful, instead of growth, the end result will be death of the mosquito.


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