Genetically modified mosquitoes could prove effective in tackling dengue fever

[hvactec]

Genetically modified mosquitoes could prove effective in tackling dengue fever and other insect-borne diseases, a UK-based scientific team has shown.

The male mosquitoes are modified so their offspring die before reproducing.

In a dengue-affected part of the Cayman Islands, researchers found the GM males mated successfully with wild females.

In Nature Biotechnology journal, they say such mating has not before been proven in the wild, and could cut the number of disease-carrying mosquitoes.

Dengue is caused by a virus transmitted by the Aedes aegypti mosquito as it bites.

The World Health Organisation (WHO) estimates that there may be 50 million cases each year, and the incidence is rising, with some countries reporting what the WHO terms "explosive" outbreaks.

As yet, there is no vaccine.

Radiation damage

As far back as the 1940s, it was realised that releasing sterile males into the wild could control insects that carried disease or were agricultural pests.

When females breed with the sterile males rather than wild fertile ones, there will be no viable offspring, meaning there are fewer mosquitoes around to transmit the disease.

In the 1950s, the screwworm fly was eradicated from the Caribbean island of Curacao using males sterilised by radiation.

But the technology has not worked so well with disease-carrying insects.

Generally, the sterilising process weakens the males so much that they struggle to mate; the wild males are dominant.

Oxitec, a company spun off from Oxford University, uses a genetic engineering approach.

Offspring of their GM males live through the larval stage but die as pupae, before reaching adulthood.

In the latest study, the research group - which includes scientists from Imperial College London and the Liverpool School of Tropical Medicine - released batches of GM mosquitoes in 2009 in an area of the Cayman Islands where Aedes aegypti are common, and dengue sometimes present.

read more BBC News - GM mosquitoes show fever promise

 

[Old Rocks]

I hope it works. But before considering applying it to all mosquito species, one should consider their place in the ecology.

 

[waltky]

Mosquitoes are being genetically engineered to kill their own offspring...

Mosquitoes may be used to kill their offspring
Monday, October 31, 2011 - Research is arousing concern about possible unintended consequences

These mosquitoes are genetically engineered to kill - their own children. Researchers on Sunday reported initial signs of success from the first release into the environment of mosquitoes engineered to pass a lethal gene to their offspring, killing them before they reach adulthood. The results, and other work elsewhere, could herald an age in which genetically modified insects will be used to help control agricultural pests and insect-borne diseases like dengue fever and malaria.

But the research is arousing concern about possible unintended effects on public health and the environment, because once genetically modified insects are released, they cannot be recalled. Authorities in the Florida Keys, which in 2009 experienced its first cases of dengue fever in decades, hope to conduct an open-air test of the modified mosquitoes as early as December, pending approval from the federal Agriculture Department. "It's a more ecologically friendly way to control mosquitoes than spraying insecticides," said Coleen Fitzsimmons, a spokeswoman for the Florida Keys Mosquito Control District.

Other pests next?

The Agriculture Department, meanwhile, is looking at using genetic engineering to help control farm pests like the Mediterranean fruit fly, or medfly, and the cotton-munching pink bollworm, according to an environmental impact statement it published in 2008. Millions of genetically engineered bollworms have been released over cotton fields in Yuma County, Ariz. Yet even supporters of the research worry it could provoke a public reaction similar to the one that has limited the acceptance of genetically modified crops. In particular, critics say that Oxitec, the British biotechnology company that developed the dengue-fighting mosquito, has rushed into field testing without sufficient review and public consultation, sometimes in countries with weak regulations.

"Even if the harms don't materialize, this will undermine the credibility and legitimacy of the research enterprise," said Lawrence Gostin, professor of international health law at Georgetown University. The first release, which was discussed in a scientific paper published online Sunday by the journal Nature Biotechnology, took place in the Cayman Islands in the Caribbean in 2009 and caught the international scientific community by surprise. Oxitec has subsequently released the modified mosquitoes in Malaysia and Brazil. Luke Alphey, chief scientist at Oxitec, said the company had left the review and community outreach to authorities in the host countries.

Alphey was a zoology researcher at Oxford University before co-founding Oxitec in 2002. The company has raised about $24 million from investors, including Oxford University, he said. Oxitec says its approach is an extension of a technique used successfully for decades to suppress or even eradicate pests, which involves the release of millions of sterile insects that mate with wild ones, producing no offspring. But the technique has not been successfully used for mosquitoes, in part because the radiation usually used to sterilize the insects also injures them, making it difficult for them to compete for mates against wild counterparts.

10% carry the gene

 

[waltky]

Global recession affects fight against diseases...

Cash crisis hits disease battle
24 November 2011 - Projects to protect people against diseases including malaria are under threat

Efforts to tackle diseases which kill millions each year could be badly affected by a severe shortfall in donations to a worldwide funding body. The Global Fund to Fight Aids, TB and Malaria will make no new grants until 2014, and there is a threat to some existing projects. It asked international donors for $20bn, but received just $11.5bn. This misses even the fund's "minimum" $13bn target, which it says is needed to maintain programmes until 2014.

HIV charities said they were "extremely alarmed" by the decision. This is the first time in its 10 year history that the fund has been forced to cancel its three-yearly funding round. It blames the problem on a combination of "substantial budget challenges" in some of the countries who would normally contribute, and low interest rates cutting returns on its investments.

'Worst possible time'

However, in recent years it has faced accusations of failing to make sure money reached those in need, commissioning a review in March after reports of "grave misuse of funds" in four recipient countries. This led to some donors, including Germany and Sweden, holding back their funding temporarily. The HIV/Aids Alliance, whose member organisations rely heavily on the fund for projects across the world, said that it was the worst possible time for money to be withdrawn. It said that planned projects to tackle high rates of HIV in areas of China and South Sudan might be affected by the funding cut.

Alvaro Bermejo, its director, said: "These should be exciting times - the latest scientific developments are showing us that HIV treatment can have a powerful HIV prevention effect. "Never again must we reach a position where life-saving programmes are cancelled or delayed." Another medical charity, Médecins Sans Frontières, described the financial situation as "dire". He said that some countries with low HIV treatment coverage, such as Kenya, Lesotho and South Africa, had already been refused funding for larger scale programmes.

Dr Tido von Schoen-Angerer, one of its executive directors, said: "Donors are really pulling the rug out from under people living with HIV/Aids at precisely the time when we need to move full steam ahead and get life-saving treatment to more people." He called for other governments to help make up some of the shortfall in donations. The fund, which is based in Geneva, said that only "essential" programmes in low or middle-income countries would receive more funding to keep them going until 2014. It says it intends to bring in new management to improve administration.

BBC News - Cash crisis hits disease battle

 

[waltky]

Anti-malaria breakthrough...

Scientists Provide Template for Developing New Anti-malarial Drug
January 18, 2012 - In a medical breakthrough, scientists have determined the workings of a protein vital to the parasite that causes malaria, a disease that annually sickens more than 200 million people around the world, and kills more than 500,000. Researchers say their analysis of the protein reveals an important weakness in the microscopic parasite, and provides a good starting point for new anti-malarial drugs.

A team of scientists at Washington University in St. Louis, Missouri, spent six years trying to understand the structure and function of a protein essential to the survival of Plasmodium falciparum. That's the single-celled protozoan that lives inside mosquitos and is responsible for the most lethal form of malaria. The microscopic parasite needs the protein, an enzyme called PMT, to make its cell membranes, and it cannot survive without it. Dr. Joseph Jez, who led the research team, says cracking the code of PMT's design is like finding malaria's fatal weakness: "If you can target the protein and basically kill the activity of the protein, you shut down the production of building blocks for membranes which will then make the organism die off, or slow down the progression," said Jez.

Jez and his colleagues used a complex and painstaking method called protein crystallization to view PMT's molecular structure in three dimensions. He says the method was critical to their study. "If you can understand what the molecules look like in three dimensions, you can start to design or develop pharmaceuticals that target it specifically," Jez noted. "The uniqueness of it is that this is a new potential anti-parasitic target for Plasmodium and also in terms of nematodes or worms, which are parasites as well." Jez adds that because Plasmodium PMT is NOT found in human cells, any drug that targets the protein could be safely administered to humans.

Dr. Neeraj Mistry is managing director of the Global Network for Neglected Tropical Diseases. He says the research is an important step toward powerful and safe new drugs to fight the worldwide malaria plague: "It opens the door to developing new drugs that specifically affect the parasite - will not affect the host - that will not have severe side effects - will only affect the parasite," Mistry noted. "Which means that upon identification of that pathway, we might be able to come up with a unique drug that actually affects that malaria parasite." The work of identifying compounds that target the Plasmodium PMT is just beginning. But the Washington University research provides new hope not only for new anti-malarial drugs, but for compounds that can destroy a variety of disease-causing parasitic worms as well as weedy plants that all depend on the same PMT protein.

Source

 

[Ringel05]

Genetically modified mosquitoes could prove effective in tackling dengue fever and other insect-borne diseases, a UK-based scientific team has shown.

The male mosquitoes are modified so their offspring die before reproducing.

In a dengue-affected part of the Cayman Islands, researchers found the GM males mated successfully with wild females.

In Nature Biotechnology journal, they say such mating has not before been proven in the wild, and could cut the number of disease-carrying mosquitoes.

Dengue is caused by a virus transmitted by the Aedes aegypti mosquito as it bites.

The World Health Organisation (WHO) estimates that there may be 50 million cases each year, and the incidence is rising, with some countries reporting what the WHO terms "explosive" outbreaks.

As yet, there is no vaccine.

Radiation damage

As far back as the 1940s, it was realised that releasing sterile males into the wild could control insects that carried disease or were agricultural pests.

When females breed with the sterile males rather than wild fertile ones, there will be no viable offspring, meaning there are fewer mosquitoes around to transmit the disease.

In the 1950s, the screwworm fly was eradicated from the Caribbean island of Curacao using males sterilised by radiation.

But the technology has not worked so well with disease-carrying insects.

Generally, the sterilising process weakens the males so much that they struggle to mate; the wild males are dominant.

Oxitec, a company spun off from Oxford University, uses a genetic engineering approach.

Offspring of their GM males live through the larval stage but die as pupae, before reaching adulthood.

In the latest study, the research group - which includes scientists from Imperial College London and the Liverpool School of Tropical Medicine - released batches of GM mosquitoes in 2009 in an area of the Cayman Islands where Aedes aegypti are common, and dengue sometimes present.

read more BBC News - GM mosquitoes show fever promise

I see a sci-fi, horror flick coming out of this...........

 

[whitehall]

"A UK based scientific team has shown"....why am I not encouraged by that source? We can't control the mosquito population anywhere so what happens if the UK scientific team" breeds a super mosquito that transmits the plague?

 

[waltky]

More malaria deaths than first thought...

Study: Malaria Kills More People Than Previously Thought
Thursday, February 2nd, 2012: A new study shows that malaria could be killing many more people than some experts previously thought.

The study, published in the British medical journal The Lancet Friday, says more than 1.2 million people died of the mosquito-borne disease in 2010. The disease inflicted a high toll on adults as well as children, most of them in Africa.

Previous estimates said that between 70,000 and 80,000 people died of malaria annually. The new study also defies the belief that children under five are more likely to die of malaria than adults.

It was conducted by the Institute of Health Metrics and Evaluation at the University of Washington in Seattle. On the positive side, it shows that deaths linked to malaria have been declining because of access to better drugs and insecticide-treated nets.

The research was funded by the Bill and Melinda Gates Foundation. It used new data and new computer modeling to build a historical database for malaria between 1980 and 2010.

Source

 

[waltky]

Granny says is one o' dem end-time plagues inna Bible, an' we all gonna die...

Experts Troubled by New Dengue Outbreaks in Western Hemisphere
May 17, 2012 - Dengue fever - a tropical disease once confined mainly to Africa and Asia - has become a growing problem in the Americas. So far, there is no drug to treat the mosquito-borne viral disease or any vaccine to prevent the infection.

Public health experts say it has the potential to become a global health problem - more costly and difficult to control than malaria. “Dengue had been eliminated in this hemisphere for quite a while but unfortunately it got reintroduced and has been generally growing since then," said Donald Shepherd. Donald Shepherd spoke to VOA via Skype. He and his colleagues studied the economic burden of dengue fever on the Caribbean island of Puerto Rico (a U.S. territory). Shepherd says the figure they came up with was staggering. “The economic cost of dengue averages $40 million per year," he said. "For the moderate size that Puerto Rico is it’s a substantial amount of money.”

Dengue is a viral infection spread by the bite of a small, stripe-bellied mosquito called Aedes aegypti. Outbreaks commonly rise after heavy summer rains, which create stagnant-water breeding areas for the mosquitoes that carry the virus. Dengue can cause high fevers, headaches, severe muscle and joint pain, lack of appetite and fatigue. And in many parts of Asia and Africa where it is still endemic, the disease can prove fatal: “A nasty feature of dengue is something that microbiologists call 'antibodies enhancement' - such that if you have had one of the dengue serotypes and then you get another one then the second one is a more severe illness than it would have been the first time," said Shepherd.

Experts say people can usually recover from these severe bouts of dengue, even with no drugs to fight the virus. But they need to receive good medical care, especially close monitoring of bodily fluids, and proper diagnosis of dengue's high fever, -- which can be mistakenly blamed on more common causes. Dr. Dan Stinchcomb is the chief executive officer of Inviragen, which is developing a vaccine against the multiple dengue viruses. He says developing a safe vaccine has been a significant challenge.

“Because dengue is a problem that affects different ages throughout the world. In Southeast Asia it's mainly a childhood disease, but in Central and South America and other parts of Asia it can still affect adults as well," said Stinchcomb. Experts say because the cost of treating dengue victims is so high, it's important that affected countries strengthen their traditional disease surveillance, prevention, and control efforts - until a drug or vaccine is available to combat the virus.

Source

 

[nitroz]

Heres a good one: Genetically modify them to avoid most living creatures and to kill eachother.

Fucking hate mosquitos.

 

[Saigon]

I hope this works....a similar schemed worked in ridding Zanzibar of Tse Tse fly.

But what works on the Canaries wont easily work on the mainland, I'd have thought. It's too easy for mozzies to migrate from place to place as the population falls in one area.

 

[waltky]

Granny says dat's why all dem lil' babies is dyin'...

Third of malaria drugs in SE Asia are fake
22 May`12 - More than a third of malaria drugs examined by scientists in Southeast Asia were fake, and a similar proportion analysed in Africa were below standard, doctors warned on Tuesday.

"These findings are a wake-up call demanding a series of interventions to better define and eliminate both criminal production and poor manufacturing of antimalarial drugs," said Joel Breman of the Fogarty International Center at the US National Institutes of Health (NIH). Trawling through surveys and published literature, the researchers found that in seven Southeast Asian countries, 36 percent of 1,437 samples, from five categories of drugs were counterfeit. Thirty-percent of the samples failed a test of their pharmaceutical ingredients.

In 21 sub-Saharan countries, 20 percent of more than 2,500 samples tested in six drug classes turned out to be falsified, and 35 percent were below pharmaceutical norms. Sub-standard medications are a major problem in the fight against malaria, a disease which killed 655,000 people in 2010, according to the UN's World Health Organisation (WHO). Many of the drugs that are being faked or poorly manufactured are artemisin derivatives, the study said. This is a special worry, for artemisinins are the frontline treatment for malaria, replacing drugs to which the malaria parasite has become resistant.

The study says there are many causes for the problem, ranging from widespread self-prescription of drugs to shoddy controls to monitor drug quality and prosecute counterfeiters. "Poor-quality antimalarial drugs are very likely to jeopardise the unprecedented progress and investments in control and elimination of malaria made in the past decade," said Breman. Last month, studies published in The Lancet and Science journals reported that artemisin-resistant malaria which was first spotted in Cambodia in 2006 has since surged 800 kilometers (500 miles) westward to the Thailand-Myanmar border.

Source

 

[waltky]

GM cotton kills insects...

Farmers Benefit from Insect-killing Cotton
July 02, 2012 : Growing cotton that is genetically modified to kill insects improves the livelihoods of small-scale farmers more than conventional varieties, according to a new study.

Researchers found farmers raising “Bt” cotton, which is modified to produce an insect-killing protein, had 24 percent higher yields, and 50 percent higher profits, than farmers growing conventional cotton. Critics say the benefits may not last long, as other insects become bigger problems in farmers’ fields. The debate has global implications for small-scale farmers in the developing world. Millions of Indian farmers raise cotton on a hectare or two of land and subsist in poverty on $1 or $2 a day.

Fighting the cotton bollworm

Before Bt cotton arrived in India in 2002, farmers relied on chemical insecticides to control an insect pest called the bollworm. “The types of chemical insecticides that farmers use against the bollworm are among the most toxic ones,” says agricultural economist and study co-author Matin Qaim at Germany’s University of Goettingen. “And they spray quite a bit.” Bollworms also threaten U.S. cotton crops. So biotech and seed company Monsanto genetically modified cotton plants to produce their own insecticide, a bacterial protein called Bt. While organic farmers have sprayed Bt on crops for decades, many cotton growers worldwide are now using the genetically-modified, insect-resistant Bt cotton variety of the plant. Three-quarters of U.S. cotton and 90 percent of Indian cotton are now Bt.

Less control, higher price

But biotechnology critics say farmers are giving up too much control over their seed supply to multinational corporations and becoming increasingly dependent on corporate-controlled technologies. Bt seeds are more expensive than conventional seeds. Opponents say farmers buying them are going deeper and deeper into debt, driving some to suicide. But Qaim says his new study shows the opposite.

Improved standard of living

The study examines 533 cotton-growing families between 2002 and 2008. Compared with conventional farmers, Bt cotton growers are “increasing their effective yields because of lower crop damage,” Qaim says. “And that leads to higher family incomes and that leads to higher living standards, [which] leads to escape from poverty.” Bt farmers had 18 percent higher family expenditures, suggesting an increase in their standard of living. “Most of the public believes that GM crops developed by big companies…would worsen the situation of small farms and poor households,” he says. “And I think it is time to reconsider those types of prejudices.”

Limited benefit?

Research by Washington University anthropologist Glenn Stone has also found increased yields among farmers raising Bt cotton. However, he says, “It’s frequently the case that new agricultural technologies have positive impacts at first. But, what we really have to be concerned about is how sustainable impacts are going to be.” Stone says other pests besides the bollworm are now becoming bigger threats, requiring more insecticides. That may undermine the advantages of Bt cotton - and continue the debate over the risks and benefits of genetically modified crops.

Source

 

[waltky]

Hope for dengue fever vaccine...

Test of New Dengue Vaccine Shows Promise
September 14, 2012 - A clinical trial of a new vaccine against dengue fever shows progress toward fighting the most common mosquito-borne disease. The drug is less successful than hoped, but seems to be effective at preventing three of the four related viruses that cause dengue.

Dengue fever increasing

Dengue fever is endemic across the tropics, with more than 2.5 billion people in 128 countries at risk. Symptoms can range from aches and fever to circulatory failure, coma and death. Some 21,000 people die of dengue each year, and the number of cases is increasing, including outbreaks in the southeastern United States. There is no vaccine available to prevent dengue fever. Part of the difficulty in developing one is that there are four different but related types of the disease. Those who recover from infection by one type gain lifetime immunity, but only against that type. Scott Halstead, of the Dengue Vaccine Initiative, explains that they are still at risk of infection with one of the other types.

"Dengue normally produces a short acute febrile disease, sort of a flu-like disease which ends in a rash, and when you're convalescent, you have life-long immunity to the type you've been infected with, say Type 1. But you are susceptible then to either type 2 or 3 or 4, and what we've learned is that two different infections - with say, Type 1 and Type 2 - can result in a very severe catastrophic disease called dengue hemorrhagic fever, and this occurs all over the tropical world, mostly in Asia and the American tropics," Halstead explained.

New vaccine

That is why researchers are focused on developing a so-called tetravalent vaccine, modeled on the successful yellow fever vaccine, combining weakened versions of all four types of dengue virus into a single drug. Halstead, who was not involved in the new clinical trial, says the pharmaceutical company, Sanofi Pasteur, took a molecular approach to creating its vaccine. "They actually spliced the gene for each of the four dengue viruses into a yellow fever backbone. So this is a combined vaccine called a chimera, combining the yellow fever replicative machinery and the dengue surface proteins," he said. "But it is a vaccine mixture of dengue 1, 2, 3 and 4."

In the first trial to determine whether a vaccine could actually prevent the disease, Sanofi's drug was tested in 4,000 school children in Thailand. The children got three doses of either the vaccine or a placebo. Spacing the shots six months apart was meant to mimic the natural immune response people develop over time. Two years later, the vaccine seemed to have protected the children against three of the four strains, but not the most common type of the virus, which accounts for about 40 percent of severe dengue cases worldwide. But the results show that the vaccine is safe, and technologically possible.

Although Halstead and many other dengue experts expressed disappointment that Sanofi's vaccine was not more effective, they regard it as an important step forward. "The problem is, can we use a vaccine that only protects against three? In my commentary that I wrote for The Lancet, I speculated that maybe, if you could really give enough of a three-component vaccine to stop transmission, you'd actually leave just one virus, and one virus all by itself won't cause dengue hemorrhagic fever. So a lot of the really serious problems caused by dengue viruses might be controlled with a three-component vaccine," said Halstead. Sanofi is already testing its new vaccine in large Phase 3 trials involving more than 30,000 people in 10 countries, with results expected in 2014. A report about the Phase 2 trial, and Dr. Halstead's commentary, appear in the medical journal, The Lancet.

Source

 

[waltky]

Experimental dengue fever vaccine compound looks promising...

Dengue Fever Vaccine Trials Clear First Hurdle
January 24, 2013 - Human trials of an experimental dengue fever vaccine have just concluded, and the experimental compound looks promising in offering protection against the complex mosquito-borne illness that afflicts millions of people living in tropical and sub-tropical regions.

Dengue fever, spread by the bite of an infected Aedes mosquito, is caused by four different but related viruses, making the development of a vaccine difficult, according to Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. “The problem with a dengue vaccine is that unlike other viruses where if you get infected with one or vaccinated with one you’re protected, period, after you recover. Whereas with dengue since there are four types, a vaccine needs to protect you against all four, because if you are only protected against one or two, you are still susceptible to one or the other of the three or four viruses,” Fauci said.

The U.S. government-funded trial was small, involving 112 healthy men and women between the ages of 18 and 50. The purpose was to see whether the experimental vaccine, made up of live but weakened viruses, was both safe and stimulated an antibody response against all four dengue types. Researchers at Johns Hopkins School of Public Health in Baltimore, Maryland formulated four different versions of the combination vaccine, and tested a separate vaccine in each of four groups of 20 study participants. All of the dengue vaccines produced an antibody response. But one experimental compound, called TV003, induced an immune response against all four dengue viruses in 45 percent of participants. And an immune response to three viruses was seen in about 90 percent of participants.

The combination vaccine was safe, producing only a faint rash in about 60 percent of the participants, according to Fauci. “I’m cautiously optimistic that we will have a vaccine after a period of time. But again, this is in [the very early] stages - only a Phase One trial,” Fauci said. The experimental dengue vaccine will undergo more safety and effectiveness testing in Phase 2 and Phase 3 trials, with researchers looking to see how well it creates an immune response against all four dengue viruses in Brazil and Thailand, where the mosquito-borne illness is endemic. Dengue fever, also known as break bone fever, infects an estimated 50 million to 00 million people in developing countries each year. Experts say the vaccine should cost less than $1 dollar a dose to produce, making it accessible to developing countries most impacted by the disease.

Dengue Fever Vaccine Trials Clear First Hurdle

 

[waltky]

Deet's effectiveness wears off in warding off mosquitoes...

Mosquitoes ignore repellent Deet after first exposure
20 February 2013 - Deet works the first time, but for some hours afterwards it loses its power

The widely used insect repellent Deet appears to be losing its effectiveness against mosquitoes, scientists say. Researchers from the London School of Hygiene and Tropical Medicine say mosquitoes are first deterred by the substance, but then later ignore it. They say more research is needed to find alternatives to Deet, which was first developed by the US military. The research was carried out on Aedes aegypti, a species of mosquito that spreads dengue and yellow fever. The findings are published in the journal Plos One. Dr James Logan from the London School of Hygiene and Tropical Medicine, said: "The more we can understand about how repellents work and how mosquitoes detect them, the better we can work out ways to get around the problem when they do become resistant to repellents."

Human bait

Deet - or N,N-diethyl-meta-toluamide - is one of the most widely used active ingredients in insect repellents. It was developed by the US military, following its experience of jungle warfare during World War II. For many years, it was not clear exactly how the chemical worked, but recent research suggests that insects simply do not like the smell. However, there are concerns that some mosquitoes are growing resistant to it. To find out more, researchers from the London School of Hygiene and Tropical Medicine took some A. aegypti mosquitoes in the laboratory, and tempted them with a human arm covered in Deet.

As expected, the repellent put the insects off their potential meal. However, a few hours later when the same mosquitoes were offered a chance to dine again, the researchers found that the Deet was less effective. To investigate why this might be happening, the researchers attached electrodes to the insects' antenna. Dr Logan explained: "We were able to record the response of the receptors on the antenna to Deet, and what we found was the mosquitoes were no longer as sensitive to the chemical, so they weren't picking it up as well. "There is something about being exposed to the chemical that first time that changes their olfactory system - changes their sense of smell - and their ability to smell Deet, which makes it less effective."

Arms race

 

[uscitizen]

Humans have an abysmal record of modifying nature for good.

 

[waltky]

Lettin' fish eat dengue mosquitoes...

Fish assist Punjab in dengue fight
Sat, Oct 05, 2013 - On one side of the battle are the countless swarms of mosquitoes that thrive in Pakistan’s steamy summer months. On the other, vast quantities of hungry fish conscripted into a fight against a deadly virus that is reaching epidemic proportions.

Authorities battling the menace of dengue virus claim to have turned the tide against the mosquitoes that carry the disease with the help of 1.6 million fish released this year into pools, puddles, fountains and any other potential insect breeding places they can find. Punjab has waged an all-out campaign against dengue, a potentially lethal disease spread by mosquito bites — since a major outbreak in 2011 infected tens of thousands and killed more than 300 people.

APPS

Software designers were tasked to make smartphone apps to track outbreaks, the government cracked down hard on anyone who left old tires in areas where they could collect rainwater and areas of stagnant water were doused with tonnes of noxious chemicals. However, it is the release of huge numbers of fish, even into water that soon evaporates, that many credit with helping to beat back the disease, which is now surging in other areas of the country. “It’s much better than chemicals that poison the environment,” said Mohammad Ayub, director-general of Punjab’s fisheries department. “And anyway, chemicals soon get washed away by the rain.”

A paramedic treats a patient with dengue fever at a hospital in Mingora, the capital of Swat Valley, Pakistan

A typical target for the Punjab’s fish team is an acre (0.4 hectare) of murky water that forms every year in a depression squeezed between a flyover and brick factory in an unlovely outskirt of Lahore. It is one of the hundreds of puddles that fill during the monsoon season that are of little interest to anyone apart from wallowing water buffalos that make their home there. Every few months a team led by a technician in a lab coat return to the pool, test the water and then release up to a thousand voracious tilapia from giant plastic bags partially inflated with oxygen. Immediately on their release the surface of the water ripples with fish rising to gobble insects and the larvae that would otherwise quickly mature into mosquitoes.

HATCHERIES

The war on mosquitoes has demanded a significant effort by Punjab’s fisheries department, which runs hatcheries to breed the vast quantities of fish seed required to keep mosquitoes at bay. The effect has been dramatic with just more than 100 cases reported in Punjab this year, compared with 20,000 in 2011. Officials say it has also curbed other pests, not just the Aedes mosquito that carries dengue.

Fish assist Punjab in dengue fight - Taipei Times

 

[waltky]

“Subduing the enemy without fighting is the highest form of generalship...

Fight dengue fever with Sun Tzu’s ‘The Art of War’
Wed, Oct 07, 2015 - With the number of dengue fever cases in Tainan having passed the 15,000 mark, after Typhoon Dujuan a number of local residents are concerned that there may be mosquito larvae growing in the rainwater, which may exacerbate the epidemic and lead to a sharp increase in the number of cases.

Some communities have tipped rock salt into drains and ditches, while others have distributed free anti-mosquito hats and improvized　mosquito repellent to deter the mosquitoes. However, mosquito expert Chen Chin-sheng says the best form of deterrent is to tidy up the environment. It is well known that the breeding source for dengue fever is water containers, says Chen. If proper cleaning is carried out, then mosquitoes will not mature into adults. Just as Sun Tzu’s The Art of War states: “Subduing the enemy without fighting is the highest form of generalship,” says Chen.

Dengue fever pesticide fogging work continues during a drizzly morning in Tainan​

A community in the north of Tainan has distributed improvized mosquito repellent and vanilla bean paste to deter mosquitoes, however Chen believes preventing a dengue fever epidemic does not have to be that difficult. Chen says the spread of dengue fever in Taiwan mainly comes from the yellow fever mosquito and Asian tiger mosquito. Since mosquitoes like to lay their eggs in water containers, there only needs to be a thorough purge of these items and the battle can be won without a fight.

Fight dengue fever with Sun Tzu’s ‘The Art of War’<br /> 「蚊」學家建議　孫子兵法戰疫 - Taipei Times

 

[waltky]

Controlling mosquitoes with bacteria...

Bacteria Shown to Stop Transmission of Mosquito-borne Illness
October 26, 2016 | WASHINGTON — Researchers in Australia have shown that introducing a naturally-occurring bacterium in the wild, called Wolbachia, can control mosquitoes that cause Dengue fever.

Wolbachia occurs naturally in 60 percent of all insect species, but not in Aedes aegypti, say experts. That’s the mosquito that spreads dengue. The mosquito species can also transmit Zika virus, yellow fever and Chikagunya, but researchers are focusing on Dengue. Australian scientists have found a low-cost way to introduce Wolbachia into dengue-causing mosquitoes in the laboratory, stopping the virus from growing inside the mosquito and thus spreading.

Once introduced into the wild, the Wolbachia mosquitoes can breed with other mosquitoes, spreading the protective bacterium. Researchers say the method is self-sustaining, having the potential to fight the life-threatening disease. Since 2011, the investigators have conducted small-scale, open field trials in dengue-infected communities. Scientists have found that the bacterium interferes with the mosquito’s ability to transmit the virus to people that causes dengue, an illness in tropical and sub-tropical countries responsible for almost 400 million infections every year.

Health workers fumigate to prevent Dengue, Chikunguya and Zika virus, at El Angel cemetery, in Lima, Peru​

The disease severely sickens 98 million people, according to the World Health Organization, causing severe flu-like symptoms. Severe dengue can cause death, especially in children. Researchers say the trials in Australia, Vietnam, Indonesia, Brazil and Colombia are helping to refine their methods of introducing Wolbachia into wild mosquito populations.

In 2014, researchers developed and began a low-cost Wolbachia strategy for urban areas, hoping to begin large-scale trials in 2016. The work is being carried out by the non-profit Eliminate Dengue Program in collaboration with the Institute of Vector-borne Disease at Monash University in Australia. The program has begun a fund-raising effort to continue its work with Wolbachia as a way to wipe out the threat of dengue.

Bacteria Shown to Stop Transmission of Mosquito-borne Illness

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$18M Donation to Target Mosquito-borne Diseases
October 26, 2016 | WASHINGTON — An international coalition of governments and philanthropic organizations has donated $18 million to fight Zika and other mosquito-borne illnesses. The money will target the illnesses in Colombia and Brazil with a unique mosquito-control program. The funds from the U.S. Agency for International Development and the British government, as well as Britain’s Wellcome Trust and the Bill and Melinda Gates Foundation, will be used to scale up the innovative, widely praised program being developed in Australia.

Use bacteria to fight virus

Over the years, the nonprofit Eliminate Dengue Program, in collaboration with Melbourne’s Monash University, has demonstrated a way to transfer a naturally occurring bacterium in the lab, called Wolbachia, into mosquitoes that carry the dengue virus. Wolbachia is carried by 60 percent of all insect species worldwide, experts say, but not by Aedes aegypti, the type of mosquito that spreads dengue and can also transmit Zika virus, yellow fever and chikungunya.

A technician releases Aedes aegypti mosquitoes with the dengue-blocking Wolbachia bacteria at the Tubiacanga neighborhood in Rio de Janeiro​

Once infected with Wolbachia, the altered Aedes aegypti mosquitoes are unable to transmit dengue. When released into the wild, they mate with local mosquitoes, passing the bacteria to their offspring. Within a few months, the wild mosquitoes are unable to spread dengue to humans. Wolbachia works by stopping the virus from growing inside the mosquito and thus spreading. Researchers say the method of mosquito control is self-sustaining, having the potential to fight the life-threatening disease.

Trials to expand

Since 2011, the program has conducted field trials in Australia, Indonesia and Vietnam. The results show that when a high proportion of mosquitoes are infected, transmission of the virus stops. Small-scale field trials began in Rio de Janeiro, Brazil, in 2014, and last year in Bello, Colombia. According to the World Health Organization, dengue infects almost 400 million people a year, mainly in tropical and subtropical countries.

Technicians carry containers filled with Aedes aegypti mosquitoes with the dengue-blocking Wolbachia bacteria before they are released at the Tubiacanga neighborhood in Rio de Janeiro, Sept. 24, 2014. Similar work has been done in Australia, Vietnam and Indonesia.​

Severe dengue can cause death, especially in children. The newly announced donations will rapidly scale up Wolbachia deployments in Latin America, beginning in 2017, to see how well the intervention works on a broader scale and in urban settings, hopefully leading to a significant reduction in Zika, dengue and chikungunya.

$18M Donation to Target Mosquito-borne Diseases