More about Mosquitoes
Posted: Fri Aug 08, 2014 1:20 pm
I considered tacking this on to Cocosmom's thread from a few weeks back, but decided it merited its own thread.
First off, for folks on island or arriving soon, we have a chance to calibrate just how long it takes after heavy rains for a mosquito bloom to hatch out. After a very dry summer, TS Bertha dropped over 2" of rain on St. John on Saturday, August 2nd. That will be one week tomorrow; if/when folks notice a decided spike in mosquito count, post and let us know. I have seen general estimates that vary from 7 to 14 days for eggs to complete their life cycle and hatch out, but this varies with location around the world, and the specific species of mosquito. Nailing how long this cycle takes would allow visitors to better predict what the island will be like during their stay.
I would definitely second cocosmom's point that your attractiveness to mosquitoes has a strong genetic (and maybe also a dietary) basis. It's pretty common to hear that one member of a party will be singled out, while the others don't get bitten. One strategy during likely blooms is to invite a not too close, mosquito-magnet friend to accompany you. For most of the year, we have a nice breeze up on the hilltop at Coconuts and Plumeria, and haven't usually found mosquitoes to be an issue, but during a heavy bloom with slack winds, they can show up. I've have been looking into the mechanisms by which mosquitoes find us, and turned up some interesting info along the way.
A mosquito's homing in on its target has two phases. From a distance, CO2 from our exhalations is the attractant, but once a mosquito gets within a meter or two, they switch gears, and home in on odorants on our skin, and in particular, to those arising from our feet and lower legs. It's a shame that tall socks and sandals look so clueless, as socks could actually offer a fair bit of protection. Up here in New England, mosquitoes are large and slow; I can usually tell that one is sizing me up, and am pretty good at nabbing them in mid air, or swatting them before they can bite. The mosquitoes in the VI are different; they are very small, and very fast. I hardly ever get them before they get me. I think that a number of mosquito bites are mistakenly blamed on no-see-ums, since the mosquitos are so stealthy.
A variety of natural repellents (citronella, eucalyptus, geraniol, etc) offer some measure of protection, but the gold standard for many years in repelling mosquitoes has always been DEET. DEET was developed by the U.S. Army during World War II, for use in jungle combat. Science may finally be about to deliver some safer and yet very effective mosquito repellents. Last December, the peer-reviewed journal Cell published a remarkable paper on mosquitoes, in which they found that the sensing organs for skin odorants were not in the leafy antennae, as had been assumed, but rather in the maxillary palps (the mouthparts), which are also the same sensors that detect CO2. To confirm this, they actually managed to wire up to the individual neurons of these sensing receptors, and observe their electrical activity as odorants were presented. They next developed a computer program that examined the molecular models of nearly half a million compounds to find ones that would inhibit or activate that sensor. The modeling predicted a few good candidates, with one compound, ethyl pryuvate, looking to be an excellent inhibitor of mosquito odor sensing. Subsequent human testing confirmed this. They also found cyclopentanone to be a very powerful mosquito attractant. This could be used in traps, but attracting mosquitoes, even to a trap, could easily be a double-edged sword.
I purchased a copy of the paper, but it is copyright protected. Here is a link to a popular summary that the University of California Riverside published, which includes a short video with one of the scientists:
http://ucrtoday.ucr.edu/19377. It's worth reading (and watching).
A link to the actual paper is here: http://www.cell.com/cell/abstract/S0092-8674(13)01426-8 (cut and paste the whole link; the last bit isn't hyperlinked for some reason).
It turns out that ethyl pyruvate is already GRAS (Generally Recognized as Safe), and is even approved for use as a food flavoring, where it imparts a flavor described variously as "caramel / butterscotch / rum raisin". I collaborate with some molecular biologists with ready access to reagents, and one has volunteered to get me some ethyl pyruvate liquid. I will be testing this compound during our visit next month, mosquitoes willing, and will report on what I find. If anyone is on island then, I'll be the fellow who smells like rum raisin, perhaps wearing socks and sandals.
Edit: Olfactor Labs has licensed pending patents from the above research at UCR, and their website indicates that new inhibitory products may be on the way. A Ugandan test of their Kite technology platform was indiegogo's most popular crowdfunding campaign four weeks in a row, and Bill Gates tweeted about it to his twelve million followers. More info here:
www.olfactorlabs.com/our-solutions-2
www.olfactorlabs.com/technology
www.olfactorlabs.com/about-us
All the best,
Kevin
First off, for folks on island or arriving soon, we have a chance to calibrate just how long it takes after heavy rains for a mosquito bloom to hatch out. After a very dry summer, TS Bertha dropped over 2" of rain on St. John on Saturday, August 2nd. That will be one week tomorrow; if/when folks notice a decided spike in mosquito count, post and let us know. I have seen general estimates that vary from 7 to 14 days for eggs to complete their life cycle and hatch out, but this varies with location around the world, and the specific species of mosquito. Nailing how long this cycle takes would allow visitors to better predict what the island will be like during their stay.
I would definitely second cocosmom's point that your attractiveness to mosquitoes has a strong genetic (and maybe also a dietary) basis. It's pretty common to hear that one member of a party will be singled out, while the others don't get bitten. One strategy during likely blooms is to invite a not too close, mosquito-magnet friend to accompany you. For most of the year, we have a nice breeze up on the hilltop at Coconuts and Plumeria, and haven't usually found mosquitoes to be an issue, but during a heavy bloom with slack winds, they can show up. I've have been looking into the mechanisms by which mosquitoes find us, and turned up some interesting info along the way.
A mosquito's homing in on its target has two phases. From a distance, CO2 from our exhalations is the attractant, but once a mosquito gets within a meter or two, they switch gears, and home in on odorants on our skin, and in particular, to those arising from our feet and lower legs. It's a shame that tall socks and sandals look so clueless, as socks could actually offer a fair bit of protection. Up here in New England, mosquitoes are large and slow; I can usually tell that one is sizing me up, and am pretty good at nabbing them in mid air, or swatting them before they can bite. The mosquitoes in the VI are different; they are very small, and very fast. I hardly ever get them before they get me. I think that a number of mosquito bites are mistakenly blamed on no-see-ums, since the mosquitos are so stealthy.
A variety of natural repellents (citronella, eucalyptus, geraniol, etc) offer some measure of protection, but the gold standard for many years in repelling mosquitoes has always been DEET. DEET was developed by the U.S. Army during World War II, for use in jungle combat. Science may finally be about to deliver some safer and yet very effective mosquito repellents. Last December, the peer-reviewed journal Cell published a remarkable paper on mosquitoes, in which they found that the sensing organs for skin odorants were not in the leafy antennae, as had been assumed, but rather in the maxillary palps (the mouthparts), which are also the same sensors that detect CO2. To confirm this, they actually managed to wire up to the individual neurons of these sensing receptors, and observe their electrical activity as odorants were presented. They next developed a computer program that examined the molecular models of nearly half a million compounds to find ones that would inhibit or activate that sensor. The modeling predicted a few good candidates, with one compound, ethyl pryuvate, looking to be an excellent inhibitor of mosquito odor sensing. Subsequent human testing confirmed this. They also found cyclopentanone to be a very powerful mosquito attractant. This could be used in traps, but attracting mosquitoes, even to a trap, could easily be a double-edged sword.
I purchased a copy of the paper, but it is copyright protected. Here is a link to a popular summary that the University of California Riverside published, which includes a short video with one of the scientists:
http://ucrtoday.ucr.edu/19377. It's worth reading (and watching).
A link to the actual paper is here: http://www.cell.com/cell/abstract/S0092-8674(13)01426-8 (cut and paste the whole link; the last bit isn't hyperlinked for some reason).
It turns out that ethyl pyruvate is already GRAS (Generally Recognized as Safe), and is even approved for use as a food flavoring, where it imparts a flavor described variously as "caramel / butterscotch / rum raisin". I collaborate with some molecular biologists with ready access to reagents, and one has volunteered to get me some ethyl pyruvate liquid. I will be testing this compound during our visit next month, mosquitoes willing, and will report on what I find. If anyone is on island then, I'll be the fellow who smells like rum raisin, perhaps wearing socks and sandals.
Edit: Olfactor Labs has licensed pending patents from the above research at UCR, and their website indicates that new inhibitory products may be on the way. A Ugandan test of their Kite technology platform was indiegogo's most popular crowdfunding campaign four weeks in a row, and Bill Gates tweeted about it to his twelve million followers. More info here:
www.olfactorlabs.com/our-solutions-2
www.olfactorlabs.com/technology
www.olfactorlabs.com/about-us
All the best,
Kevin
My first approach will be to dissolve some ethyl pyruvate in witch hazel and spray it on my clothes, but I will also try some applied directly to skin. Both liquids have a base alcohol-like smell to them, but I can see where the ethyl pyruvate came by its rum-raisin description.
They always LOVE me and the feeling is NOT mutual!