Although Malaria takes the headlines, Dengue Fever—a painful, fever-inducing virus with no specific treatment—is the mosquito’s most deadly weapon. The World Health Organisation estimates that it causes 10,000 deaths and 100 million infections per year.
Governments try to combat the tropical disease with nets and insecticide sprays. Scientists have tried genetically engineering mosquitoes into extinction, preventing them from reproducing.
It’s not yet enough. Recent research has found that more than six billion people are at risk of contracting the disease by 2080.
But, maybe there’s an innovation to get excited about. Science magazine reports that researchers have been injecting a type of bacteria, Wolbachia, into the eggs of ‘Aedes aegypti’ mosquitoes (the ones that spread dengue) for the past eight years. It’s a normal kind of bacteria, often present in other mosquitoes.
What’s important is that Wolbachia prevents the spread of disease from mosquito to human. It’s a type of bacteria that stays within the mosquito family, passed from offspring to offspring.
The aim? A raft of diseases, including dengue, Zika and Chikungunya, to never again infect humans.
Science magazine stresses that it takes a long time to test whether such attempts have been successful. But, Science reports that in preliminary results from trials in tropical areas, conducted by the World Mosquito Programme, there’s been an up to 76 percent reduction in the rate of dengue fever.
The magazine goes on to note that in controlled trials, on the outskirts of Yogakarta in Indonesia, local health officials found up to a 75 percent reduction in dengue infections in the 2.5 years after the release of the bacteria-powered mosquitoes. Similar results were found for chikungunya in a part of Brazil.
No one is under any illusions: These studies are just a first step. Results to date have been drawn from public health surveillance data, which can have inaccuracies and misdiagnoses. In Vietnam, a hotter climate, the bacteria dropped out.
But experts, according to Science, say it’s all worth getting excited about. Several studies have found similar effects, with the end result being that fewer people contract a deadly disease. The teams are now conducting larger trials, aiming to identify dengue patients in hospitals and work out what proportion come from the infected mosquito area.
And in the future? Science says that if all goes well, the WHO may end up approving the microbe for broader use.
Michael Acton Smith