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Mosquitoes: Research Toward Negating Them As Disease Vectors

meowfur

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http://www.azcentral.com/offbeat/articl ... to-ON.html

Scientist seeks way to make mosquitoes pee themselves to death
Reno Gazette-Journal
Sept. 21, 2005 05:10 PM

RENO, Nev. - In a combination laboratory-office lined with beakers, petri dishes and a glass case of Madagascar hissing cockroaches, a Reno biochemist is searching for a way to make mosquitoes pee themselves to death.

By finding the key that would cause mosquitoes to meet their urinary demise by dehydration, University of Nevada, Reno professor David Schooley and his fellow researchers hope to end the hundreds of thousands of deaths caused each year by mosquito-spread malaria and to halt the spread of West Nile virus.

Schooley came closer to realizing that goal five years ago when he discovered a diuretic hormone that causes a dramatic increase in how much mosquitoes urinate.

"The reason we think this has a good chance of working is because, after a blood meal, a mosquito more than doubles its weight," Schooley said. "That means it has to get rid of an enormous amount of fluid after feeding. It's like a 747 with 1,000 people on board. It has to lighten the load in order to take off."

After a mosquito finishes its meal - and only the female bites to feed the eggs she carries - it begins excreting salt and water from the blood it has just ingested, Schooley said.

"What we would hope is if we treat the mosquito ... before it has its blood meal, it will dehydrate and die," he said.

In tests, the hormone - a calcitonin-like peptide - worked when it was applied directly to what is the equivalent of the mosquito's kidney. The problem is the peptide doesn't penetrate the mosquito's body when sprayed on it. So the challenge Schooley and his fellow researchers face is finding something similar that can penetrate mosquitoes and reach their Malpighian tubules, their equivalent of kidneys.

"What I want to find is a simpler, smaller molecule than the C-T peptide with the same biological effect on the mosquito," said Schooley. Finding that key molecule to make mosquitoes vulnerable to a new pesticide could be 10 years away, he said.

He is being aided by Geoff Coast, a physiologist with Birkbeck College of the University of London. Coast studies the effects on mosquitoes of peptides Schooley synthesizes. They are co-principals in the research project, which is funded by a $927,000 grant from the National Institutes of Health.

The implications of their recent discovery appeared in this month's issue of the Journal of Experimental Biology.

William Hawley, a malaria biologist with the Centers for Disease Control and Prevention, said most malaria specialists agree it isn't feasible to eradicate mosquitoes, but the goal is to reduce their life span so they don't transmit the disease.

Hawley said mosquitoes begin life free of malaria, and it is not until they bite someone who has the disease that they become infected. However, even after biting an infected person, it takes about 10 days for the parasite to complete its life cycle, at which time the mosquito begins transmitting the disease.

"What research like this does, if they can work out a delivery system, is reduce the life span of mosquitoes so they would be rendered incapable of transmitting malaria," Hawley said.

"And we need all the help we can get," he said. "Malaria is killing about a million people annually around the world."

Malaria is a curable disease, Hawley said, but the disease kills very quickly if left untreated, and most people in the developing countries primarily affected by malaria are poor and can't afford treatment.

"About 80 percent of the cases of malaria are in Africa, where 90 percent of the deaths are mostly children under the age of 5," he said. "So malaria remains one of the major killers of people in the world."

The United States reported 1,337 cases of malaria, including eight deaths, in 2002, the most recent statistics available, according to the CDC's Web site. All but five of the 1,337 cases were acquired by people traveling in other countries.

The disease was virtually eradicated in this country during the early 1950s, but the CDC notes that the two species of mosquitoes responsible for transmitting malaria in the U.S. before its eradication are still widely prevalent.

If the current research results in a new pesticide to control mosquitoes, Schooley said the impact would be ridding the world of such deadly diseases.

"It would mean a revolutionary new way of killing adult mosquitoes with a chemical unlikely to affect mammals while preventing diseases like malaria and West Nile virus," he said.

File under "WTF?" :wtf:
 
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This is cruelty against insects!
Where's the animal rights activists when they're needed? ;)
 
Interesting though with the advent of genetic modification if there are any unforseen adverse consequences to eradicating a pest? Obviously likely to do far more good for mankind but what if say, the common fly did not exist? No maggots to break down dead flesh etc ...Anyone remember the film about the introduction of the Cane toad in Australia?

The "cane toad" (Bufo marinus) is a creature that was introduced to Australia to try to curb the problem of cane beetles eating sugar cane crops. Ironically they had no effect in controlling the cane beetle instead they quickly multiplied out of control. To counter the cane-toad problem the Australian people (especially Queenslanders) have tried to kill cane toads in creative ways - it hasn't been enough
http://www.cane-toad.com/about_cane01.htm
 
I agree. Wish they'd spend the time and energy on eradicating the West Nile Virus instead. I don't know what "positive" role mosquitoes play in the big scheme of things, but there's a reason it's called an eco "system."
 
SameOldVardoger said:
This is cruelty against insects!
Where's the animal rights activists when they're needed? ;)

Yeah...I'm thinking I know how the poor little buggers feel. At MY age - I'm pretty much on the verge of peeing myself to death daily.
 
Peeing someone else to death has to be where it gets interesting.

Can you dust for urine?
 
Mosquito with glowing gonads to help battle malaria

Mosquito with glowing gonads to help battle malaria
14:06 10 October 2005
NewScientist.com news service
Kurt Kleiner
A genetically engineered mosquito with glowing gonads could become a new weapon in the battle against malaria.

Researchers at Imperial College London created the mosquito by attaching a gene for fluorescence found in jellyfish to a gene expressed only in a male mosquito’s sexual organs. The technique makes it relatively simple to distinguish males from females, something that has previously hindered malaria-eradication strategies.

One way to control disease-carrying mosquitoes is to flood an area with millions of sterile males. They mate with the females but produce no offspring, so the insect population drops. The technique has helped control the Mediterranean fruit fly (Ceratitis capitata), for instance.

Go with the flow
But the strategy relies on being able to separate males from females, as sterile females can still transmit malaria. The problem is that, unlike some insects, the larvae are very difficult to sex.

Making the male larvae fluoresce solves the problem, and in fact makes them so easy to spot that the process can be automated. The researchers used a machine similar to a flow cytometer that had already been adapted to sort fruit flies.

The mosquito larvae flow past a detector in a stream of water, and when the machine detects fluorescence it uses a puff of air to divert the males into a separate area for collection. The machine sorted 180,000 larvae in 10 hours.

Turned on
To create the mosquito, researchers inserted the gene for enhanced green fluorescent protein in a position where it would be turned on by the Beta-2-tubulin promoter, which is active only in the male gonads. The mosquitoes used in the experiment were Anopheles stephensi, which carries malaria in Asia.

Andrea Crisanti, a molecular parasitologist and one of the Imperial College team, says the technique should be easy to apply to other problem mosquito species.

Peter Atkinson, an entomologist at the University of California, Riverside, says: “This is the first demonstration that it is feasible to use fluorescent expression to robotically separate males from females. If you need to release millions of mosquitoes you don’t want to sort them manually.”

Journal reference: Nature Biotechnology (DOI: 10.1038/nbt1152)

http://www.newscientist.com/article.ns?id=dn8120

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Weblinks
Andrea Crisanti
http://www.bio.ic.ac.uk/research/acrs/
Malaria, WHO
http://www.who.int/mediacentre/factshee ... index.html
Peter Atkinson, University of California, Riverside
http://www.cell.ucr.edu/index1.php?cont ... index.html
Nature Biotechnology
http://www.nature.com/nbt/
 
Must....resist....the....temptation to predict any resultant Hollywood disaster arising from this venture. Sounds logical, safe, predictable and without any possible downsides. (And, there's no mention of having extracted DNA from ancient mosquitos trapped in amber, so that's reassuring)

http://www.newscientist.com/article...-begin-blitz-on-dengue-in-brazilian-city.html

"The insect assassins have been launched. Millions of genetically modified mosquitoes have descended on the Brazilian city of Piracicaba in the battle against dengue and a test in Florida is also in prospect.

The GM mosquitoes are all male, and when they mate with native females, they pass on a gene to offspring that causes the larvae to die before they mature.

The plan is to flood the area with GM mozzies to outnumber native males, gradually whittling down the numbers of dengue-transmitting mosquitoes.

The GM mosquitoes were designed by Oxitec of Abingdon, UK, and are bred en masse in a factory in Campinas, Brazil. The firm has a permit to commercialise and release the mozzies anywhere in Brazil.

Oxitec is also waiting for a permission from the US Food and Drug Administration (FDA) to test the mosquitoes on Key Haven in the Florida Keys.

Since April, 6 million GM mozzies have been released in the suburb of Piracicaba that is worst infested by Aedes aegypti, a mosquito that spreads the dengue fever virus.

"They've asked us to take on the neighbourhood that's the worst to prove it works," says Hadyn Parry, chief executive of Oxitec. "We hope that if it does, we can expand to a larger number of areas."

Results up in lights
The GM mosquitoes also carry a gene that makes the larvae they sire glow red under ultraviolet light, which allows scientists to see by eye how well the strategy is working.

By leaving pots of water, in which female mosquitoes lay eggs, at strategically important sites in the treatment zone, researchers can tell by counting the proportion of red larvae how well the treatment is working.

"It gives an instant readout of how successfully you're driving down the native population," says Parry.

So far, the pot-survey has revealed that half of the larvae in the area have been sired by the GM mosquitoes. "Reaching 50 per cent already means we're on the same eradication curve as we've seen in earlier trials," he says."
 
Must....resist....the....temptation to predict any resultant Hollywood disaster arising from this venture. Sounds logical, safe, predictable and without any possible downsides. (And, there's no mention of having extracted DNA from ancient mosquitos trapped in amber, so that's reassuring)

http://www.newscientist.com/article...-begin-blitz-on-dengue-in-brazilian-city.html
You're right to wonder whether there could be a downside to this sort of thing. Possibly mozzies play some unsuspected but vital role in the ecosystem, and that with no mozzies some other problem might arise.

All we amateurs can do is hope that the researchers have thought of every possibility, and have determined that there is no downside.

Fingers crossed!
 
And if it does go wrong Britain will be blamed, YIPEEEEEEEE
 
Possibly mozzies play some unsuspected but vital role in the ecosystem, and that with no mozzies some other problem might arise.

Isn't malaria one of the biggest killers of Humans? Could no mozzies = population explosion? There's a thread for that somewhere...
 
And if it does go wrong Britain will be blamed, YIPEEEEEEEE
We're to blame for many of the world's ills, so one more thing just gets added to the pile.
 
And if it does go wrong Britain will be blamed, YIPEEEEEEEE
'Twas ever so.

And yes, @rynner2 , perhaps the existing mosquitos do fill an unseen vital ecological niche, which will destroy us in a way that's much more subtly-catastrophic than david's human overpopulation.

I am reminded of my (possibly-unsound) understanding that lead-free petrol killed-off many roadside hedgerow insects (daddy longlegs/waterboatmen/clegs etc), which happily thrived on leaded 4-star fumes. As a consequence (allegedly or scientifically-proven) the songbird population dived within weeks, and hence our underwhelming clutch of nice birds (crows and co do not apply)
 
This (or perhaps a parallel / copy-cat) Brazilian initiative didn't work out as planned ...
A Trial That Gene-Hacked Mosquitoes to Stop Breeding Has Backfired Spectacularly

On its surface, the plan was simple: gene-hack mosquitoes so their offspring immediately die, mix them with disease-spreading bugs in the wild, and watch the population drop off. Unfortunately, that didn't quite pan out.

The genetically-altered mosquitoes did mix with the wild population, and for a brief period the number of mosquitoes in Jacobino, Brazil did plummet, according to research published in Nature Scientific Reports last week.

But 18 months later the population bounced right back up, New Atlas reports - and even worse, the new genetic hybrids may be even more resilient to future attempts to quell their numbers.

Desperate Times

Mosquitoes capable of transmitting dangerous diseases like Zika, dengue, and malaria are spreading farther than ever, thanks to global climate change. To combat them, scientists have sometimes tried to alter the bugs' genetics so that they couldn't reproduce.

"The claim was that genes from the release strain would not get into the general population because offspring would die," Yale researcher Jeffrey Powell, one of the researchers behind the new paper, told New Atlas. "That obviously was not what happened."

Playing God

In Brazil, the wild mosquitoes mated with the gene-hacked population and created a new sort of genetic hybrid that's more robust than the wild bugs were.

While the new variant isn't inherently dangerous - or at least not additionally so - the scientists behind the project say they don't fully understand how things will change for future generations.

"It is the unanticipated outcome that is concerning," Powell told New Atlas.
FULL STORY: https://www.sciencealert.com/a-tria...-to-stop-breeding-has-backfired-spectacularly

NOTE: This is a re-publication of the following article:

https://futurism.com/the-byte/gene-hack-mosquitoes-backfiring
 
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I had an idea this just wouldn't work.
 
Scientists researching mostquitoes' remarkable ability to locate human "prey" have discovered some mosquitoes are using an olfactory system organized unlike anything previously known. Its novelty is sufficient to challenge canonical assumptions about how olfactory systems work.
There is a 'Shockingly Weird' Reason Mosquitoes Always Seem to Find Us, Says Study

The relentless accuracy with which some mosquito species hunt down humans may result from their bizarrely wired olfactory system, which has an in-built backup for detecting human scents.

Mosquitoes can sense CO2 or sweat wafting off humans using unique chemoreceptors in their antennae and the maxillary palp, a jointed sensory appendage of insects.

A new study led by researchers at Boston University and Rockefeller University explains why mosquitoes are so good at sensing us, even when researchers genetically disable human-specific chemoreceptors.

According to the study, at least one mosquito species, Aedes aegypti, has an entirely different way of organizing its olfactory system compared to most animals. ...

It turns out that A. aegypti connects several olfactory sensory receptors to the one neuron, a process called coexpression.

According to this team, this overturns a core principle of olfactory science, which states that each neuron only has one chemoreceptor associated with it.

"This is shockingly weird," says Boston University neuroscientist and senior author Meg Younger. "It's not what we expected."

"The central dogma in olfaction is that sensory neurons, for us in our nose, each express one type of olfactory receptor," says Younger. ...

"The redundancy afforded by an olfactory system … may increase the robustness of the mosquito olfactory system and explain our long-standing inability to disrupt the detection of humans by mosquitoes," the researchers conclude. ...
FULL STORY: https://www.sciencealert.com/there-...-mosquitoes-always-seem-to-find-us-says-study
 
Here are the bibliographic details and summary for the published research report. The full report is accessible at the link below.


Non-canonical odor coding in the mosquito
Margaret Herre, Olivia V. Goldman, Tzu-Chiao Lu, et al.
Cell VOLUME 185, ISSUE 17, P3104-3123.E28, AUGUST 18, 2022
DOI:https://doi.org/10.1016/j.cell.2022.07.024

Summary
Aedes aegypti mosquitoes are a persistent human foe, transmitting arboviruses including dengue when they feed on human blood. Mosquitoes are intensely attracted to body odor and carbon dioxide, which they detect using ionotropic chemosensory receptors encoded by three large multi-gene families. Genetic mutations that disrupt the olfactory system have modest effects on human attraction, suggesting redundancy in odor coding. The canonical view is that olfactory sensory neurons each express a single chemosensory receptor that defines its ligand selectivity. We discovered that Ae. aegypti uses a different organizational principle, with many neurons co-expressing multiple chemosensory receptor genes. In vivo electrophysiology demonstrates that the broad ligand-sensitivity of mosquito olfactory neurons depends on this non-canonical co-expression. The redundancy afforded by an olfactory system in which neurons co-express multiple chemosensory receptors may increase the robustness of the mosquito olfactory system and explain our long-standing inability to disrupt the detection of humans by mosquitoes.

SOURCE / FULL REPORT: https://www.cell.com/cell/fulltext/...m/retrieve/pii/S0092867422009278?showall=true
 
Deadly dengue outbreak.

Argentina is battling a record outbreak of dengue fever, which has killed more than 40 people and infected more than 60,000, mainly in the north-west.

The infection is spread by Aedes aegypti mosquitoes, and the last big outbreak to hit Argentina was in 2020. The health ministry says dengue cases are starting to plateau, however.

Biologists are irradiating thousands of male mosquitoes in labs, to be released later, in the hope that their offspring will be unviable because of DNA damage.

"This mosquito, due to the rise in temperature in our country and the world... is able to spread more. Their population keeps on moving further south," biologist Marianela Garcia Alba said, quoted by Reuters news agency. The aim is to make the mosquitoes that have been exposed to radiation the dominant type, to curb the spread of dengue, she added.

The north-western provinces of Salta, Tucumán and Jujuy, near Argentina's borders with Chile and Bolivia, have recorded the highest numbers of deaths.

https://www.bbc.com/news/world-latin-america-65356495
 
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