Nav: Home

Releasing artificially-infected mosquitoes could reduce global dengue cases by 90%

January 29, 2020

This is the finding of a team of international scientists, led by Imperial College London, and including researchers from the University of California and University of Florida.

The Imperial team, based at J-IDEA, the Abdul Latif Jameel Institute for Disease and Emergency Analytics, created the first ever global map of dengue transmission intensity - which is a measure of how easily dengue is transmitted from person to person.

Using this map, the researchers predicted the global effectiveness of two interventions to combat dengue - vaccination and the release of 'infected' mosquitoes unable to transmit the virus between people.

Scientists infect mosquitoes in the laboratory with a type of naturally-occurring bacteria called Wolbachia, which prevents the virus replicating in the insect. In carefully-controlled trials, releasing these modified mosquitoes in areas heavily affected by dengue has been linked to a 70 per cent reduction in cases, though scientists caution this has to be confirmed in larger trials.

The study was published in the journal Science Translational Medicine, and funded by the Medical Research Council, National Institute for Health Research, the National Institute of General Medical Sciences, and the Department for International Development.

The new map is online and freely-available.

Dr Lorenzo Cattarino, lead author of the research from the MRC Centre for Global Infectious Disease Analysis, said: "Dengue is a leading cause of illness and death among children across the globe. Our research not only produces the first world map of dengue transmission, but can act as a tool to inform the World Health Organisation, local governments and policy makers on the effectiveness of prevention strategies, such as the release of Wolbachia-infected mosquitoes and vaccination programmes."

Dengue is a viral infection that infects over 100 million people each year. According to the latest estimates, around half of the world's population are thought to be at risk. The virus is spread by mosquitoes, and causes fever, headache, muscle and joint pain. In some cases, it can lead to a life-threatening condition called haemorrhagic fever which is a leading cause of death and serious illness among children in some Asian and Latin American countries.

There is no specific treatment for the disease, and prevention centres around avoiding mosquito bites - for instance using insecticides and reducing areas of standing water where the insects can breed, such as plastic containers.

However two methods of preventing infections have recently emerged that show promise of combatting the disease. A vaccine is now licensed for use against dengue, which works by reducing the intensity of subsequent dengue infections. There are four different types of dengue and therefore people can catch the disease four times. However, the vaccine can only be used in people previously infected with dengue (and thus requires people to be tested for dengue first). This is because the vaccine may prime a person's immune system to 'over-react' to a subsequent dengue infection if they haven't encountered the virus before, making the disease more severe.

Another method of prevention is disabling mosquitoes' ability to transmit the virus, by infecting them with the bacteria Wolbachia.

This bacteria is found naturally in around 60 per cent of insect species, including some mosquitoes, butterflies and moths.

Previous laboratory research has shown mosquitoes infected with Wolbachia do not transmit dengue, as the bacteria stops the virus replicating inside the insect.

In carefully controlled trials, scientists are now purposefully infecting the mosquito species that carry dengue - called Aedes aegypti - with Wolbachia, and releasing them into areas infected with dengue.

The trials suggest the bacteria does not pose a threat to animals or people in the areas where the mosquitoes are released.

Using data from these laboratory and mathematical modelling studies, the scientists behind the latest study used their map to predict this approach could eliminate nearly all dengue cases worldwide.

They also modelled the effectiveness of the Sanofi Pasteur dengue vaccine if used in all areas affected by dengue, and found the number of dengue cases could be reduced by up to 30 per cent. This is because the vaccine reduces the probability of becoming severely ill, rather than virus transmission.

The team highlight caveats in their study. The predictions assume the effectiveness of the mosquitoes in small-scale trials will be replicated on a global scale, and that the diagnostic test for dengue screening, which is recommended before the vaccine can be administered, is 95 per cent accurate. The researchers add that the two interventions were modelled separately.

Professor Neil Ferguson, co-lead author of the research, and head of Imperial's Department of Infectious Disease Epidemiology said: "Until now, gauging the effectiveness of control strategies for dengue, such as vaccine and Wolbachia-infected mosquitoes, has been limited by the lack of data on transmission across large geographical regions. The creation of this freely available global map of transmission, and the likely impact of control measures, will help identify strategies to reduce the number of people affected by the disease. The cost-effectiveness of these strategies can also be assessed, which is particularly important when most areas affected by dengue are in lower income nations."

Imperial College London

Related Bacteria Articles:

Siblings can also differ from one another in bacteria
A research team from the University of Tübingen and the German Center for Infection Research (DZIF) is investigating how pathogens influence the immune response of their host with genetic variation.
How bacteria fertilize soya
Soya and clover have their very own fertiliser factories in their roots, where bacteria manufacture ammonium, which is crucial for plant growth.
Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.
Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.
Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.
Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.
Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.
How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.
The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?
Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.
More Bacteria News and Bacteria Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at     You can read The Transition Integrity Project's report here.