Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Evolution-proof insecticides may stall malaria forever

08.04.2009
Killing just the older mosquitoes would be a more sustainable way of controlling malaria, according to entomologists who add that the approach may lead to evolution-proof insecticides that never become obsolete.

Each year malaria -- spread through mosquito bites -- kills about a million people, but many of the chemicals used to kill the insects become ineffective. Repeated exposure to an insecticide breeds a new generation of mosquitoes that are resistant to that particular insecticide.

"Insecticides sprayed on house walls or bed nets are some of the most successful ways of controlling malaria," said Andrew Read, professor of biology and entomology, Penn State. "But they work by killing the insects or denying them the human blood they turn into eggs. This imposes an enormous selection in favor of insecticide-resistant mosquitoes."

Read and his colleagues Matthew Thomas, professor of entomology, Penn State, and Penelope Lynch, doctoral student, Open University, UK, argue that insecticides -- chemical or biological -- that kill only older mosquitoes are a more sustainable way to fight the deadly disease.

"If we killed only older mosquitoes we could control malaria and solve the problem of resistant mosquitoes," said Read. "This could be done by changing the way we use existing insecticides, even by simply diluting them," he added.

Aging mosquitoes are easier to kill with insecticides like DDT but new generation pesticides could do it too. Read and his colleagues are working with a biopesticide that kills older mosquitoes.

"It is one of the great ironies of malaria," explained Read, whose team's findings appear today (April 7) in PLoS Biology. "Most mosquitoes do not live long enough to transmit the disease. To stop malaria, we only need to kill the old mosquitoes."

Since most mosquitoes die before they become dangerous, late-acting insecticides will not have much impact on breeding, so there is much less pressure for the mosquitoes to evolve resistance, explained Read, who is also associated with the Penn State Center for Infectious Disease Dynamics. "This means that late-life insecticides will be useful for much, much longer -- maybe forever -- than conventional insecticides," he added. "Insects usually have to pay a price for resistance, and if only a few older mosquitoes gain the benefits, evolutionary economics can stop resistance from ever spreading."

"We are working on a fungal pesticide that kills mosquitoes late in life," said Thomas. "We could spray it onto walls or onto treated materials such as bed nets, from where the mosquito would get infected by the fungal spores." The fungi take 10 to 12 days to kill the insects. This achieves the benefit of killing the old, dangerous mosquitoes, while dramatically reducing the selection for the evolution of resistance, Thomas explained.

To study the impact of late-acting insecticides on mosquito populations, the researchers constructed a mathematical model of malaria transmission using factors such as the egg laying cycle of the mosquito and the development of parasites within the insect.

Once malaria parasites infect a mosquito, they need at least 10 to 14 days -- or two to six cycles of egg production -- to mature and migrate to the insect's salivary glands. From there they can pass into humans when a mosquito bites.

Analyses of the model using data on mosquito lifespan and malaria development from hotspots in Africa and Papua New Guinea reveal that insecticides killing only mosquitoes that have completed at least four cycles of egg production reduce the number of infectious bites by about 95 percent.

Critically, the researchers also found that resistance to late-acting insecticides spreads much more slowly among mosquitoes, compared to conventional insecticides, and that in many cases, it never spreads at all.

Read says the development of biological or chemical insecticides that are more effective against older, malaria-infected mosquitoes could save the millions dollars that will have to be spent to endlessly find new insecticides to replace ones that have become ineffective.

"Insecticides that kill indiscriminately impose maximal selection for mosquitoes that render those insecticides useless. Late-life acting insecticides would avoid that fate," Read added. "Done right, a one-off investment could create a single insecticide that would solve the problem of mosquito resistance forever."

Amitabh Avasthi | EurekAlert!
Further information:
http://www.psu.edu

More articles from Health and Medicine:

nachricht Hot cars can hit deadly temperatures in as little as one hour
24.05.2018 | Arizona State University

nachricht 3D images of cancer cells in the body: Medical physicists from Halle present new method
16.05.2018 | Martin-Luther-Universität Halle-Wittenberg

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

When corals eat plastics

24.05.2018 | Ecology, The Environment and Conservation

Surgery involving ultrasound energy found to treat high blood pressure

24.05.2018 | Medical Engineering

First chip-scale broadband optical system that can sense molecules in the mid-IR

24.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>