Science, Nature and Tech

SCIENCE NEWS – What is Dengue Fever and Could Genetically-Modified Mosquitoes Prevent It?

Dengue (pronounced den-gee) fever affects between 50-100 million people each year, with around 25,000 people dying from the disease. It’s most common in south America and parts of Africa, and is also known as breakbone fever because it causes such intense pain in the bones. Dengue fever is a virus that’s spread by mosquitoes, and there is no vaccine or effective drug treatment to prevent or cure it.

Can it Be Prevented? 




Mosquito nets over beds are a common way of preventing the spread of malaria; unfortunately this doesn’t work with dengue fever because the mosquitoes that carry it bite during the day as well as at night.

Anti-mosquito sprays might be an option, but they would have to be used over a very large area. They would also affect other species and could get into the food chain. And really – no one wants their house to be sprayed like this!


What is the New Idea?


Photo by Oxitec

Photo by Oxitec – the DNA also contains a fluorescent gene to help the modified mosquitoes be identified


A small, UK-based company called Oxitec have had a very clever idea; they’ve given the mosquitoes an extra gene which stops them being able to reproduce.

If enough of these altered mosquitoes are released in a particular area, the population will become significantly smaller and dengue fever will almost disappear.

In many areas where dengue fever is common, mosquitoes aren’t native to the area but are invaders, so the local ecosystems won’t be harmed by their absence.



Does it Really Work? 


Photo via Oxitec of the mosquito eggs being injected with DNA

Photo via Oxitec of the mosquito eggs being injected with DNA


Oxitec have tested this idea in the Cayman Islands, Malaysia and Brazil and within 4 months of releasing the modified mosquitoes into the wild, the population had decreased by 85%.

The results of these tests were so good that a factory is being opened in Brazil in order to produce and release the new type of mosquito.


Isn’t Genetic Modification a bit Risky?



Some people are very unhappy about the idea of changing genes in animals and plants. They believe that it would be a big problem if the altered species breed with normal species, as scientists would no longer be able to control when or how the genes are passed on.

That’s not a problem with this technique though, as the whole point is to prevent the mosquitoes from breeding at all. Even if one of the changed mosquitoes did bite a human, the gene isn’t toxic for people and can’t be passed on through the mosquito’s saliva.
This new technique sounds really promising and could save a lot of lives.

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