DEET discussion from been busy diving thread

[tridacna]

Don't think so. It is always better to apply the repellent to clothing rather than than skin. Where do you come up with this?

Google is your friend. Permethrin for clothing. DEET or Picaridin for skin. It is mostly useless to apply DEET to clothing.

 

[Esprise Me]

Google is your friend. Permethrin for clothing. DEET or Picaridin for skin. It is mostly useless to apply DEET to clothing.

I Googled it and found no support for the assertion that DEET must be applied to skin in order to be effective. What's your source?

 

[tridacna]

I Googled it and found no support for the assertion that DEET must be applied to skin in order to be effective. What's your source?

My cousin is a chemist working at 3M. One of his products is Ultrathon (DEET). According to him, the vapor barrier created by DEET from an inert object has no impact on a female mosquito looking to feed. Mosquitoes are attracted to the CO2 produced by mammals - DEET masks that from mosquitoes. That's why they ignore you.

Manufacturers are quite content to let people spray vast quantities of a most profitable product on hats, shirts, socks, shoes and pants. Empties the spray can even faster. Their instructions however always state to spray it on skin only. Permethrin is designed to be applied to clothing. DEET is not.

Look up: 1-Octen-3-ol for more.

 

[Manatee Diver]

I just use a Thermacell, no spraying. Just turn it on and the skeeters stay away… mostly.

 

[Esprise Me]

It may be better to avoid responding to questions with "Google is your friend" when your source is "my cousin told me..."

From a study published in the journal Current Biology in 2019:

Commonly used insect repellents hide human odors from Anopheles mosquitoes

The mode of action for most mosquito repellents is unknown. This is primarily due to the difficulty in monitoring how the mosquito olfactory system responds to repellent odors. Here, we used the Q-system of binary expression to enable activity-dependent ...

www.ncbi.nlm.nih.gov

A consensus for how DEET affects the mosquito olfactory system and alters host seeking behavior has not yet emerged. Currently, there are three hypotheses of how DEET affects mosquitoes: 1) DEET directly activates chemoreceptors (ORs, Grs, and/or IRs) on the mosquito antennae, maxillary palps, or the labella to drive repellent behavior (“smell and avoid”) [9-17]; 2) DEET modulates (‘scrambles/confuses’) OR activity in response to odorants [11, 12, 18-20]; 3) DEET acts directly on the odorant to decrease its volatility and thereby reduces the amount of attractive odorants capable of activating mosquito olfactory receptors (“masking”) [16]. These hypotheses are not necessarily mutually exclusive; DEET may have more than one mode of action.

From an earlier study, published in 2008 in PNAS:

From the Cover: Mosquitoes smell and avoid the insect repellent DEET

The insect repellent DEET is effective against a variety of medically important pests, but its mode of action still draws considerable debate. The widely accepted hypothesis that DEET interferes with the detection of lactic acid has been challenged by ...

www.ncbi.nlm.nih.gov

(Bolding mine.)

The insect repellent DEET is effective against a variety of medically important pests, but its mode of action still draws considerable debate. The widely accepted hypothesis that DEET interferes with the detection of lactic acid has been challenged by demonstrated DEET-induced repellency in the absence of lactic acid. The most recent hypothesis suggests that DEET masks or jams the olfactory system by attenuating electrophysiological responses to 1-octen-3-ol. Our research shows that mosquitoes smell DEET directly and avoid it. We performed single-unit recordings from all functional ORNs on the antenna and maxillary palps of Culex quinquefasciatus and found an ORN in a short trichoid sensillum responding to DEET in a dose-dependent manner. The same ORN responded with higher sensitivity to terpenoid compounds. SPME and GC analysis showed that odorants were trapped in conventional stimulus cartridges upon addition of a DEET-impregnated filter paper strip thus leading to the observed reduced electrophysiological responses, as reported elsewhere. With a new stimulus delivery method releasing equal amounts of 1-octen-3-ol alone or in combination with DEET we found no difference in neuronal responses. When applied to human skin, DEET altered the chemical profile of emanations by a “fixative” effect that may also contribute to repellency. However, the main mode of action is the direct detection of DEET as indicated by the evidence that mosquitoes are endowed with DEET-detecting ORNs and corroborated by behavioral bioassays. In a sugar-feeding assay, both female and male mosquitoes avoided DEET. In addition, mosquitoes responding only to physical stimuli avoided DEET.

 

[rddvet]

I just use a Thermacell, no spraying. Just turn it on and the skeeters stay away… mostly.

You will sometimes get crap travelling with thermacells on planes. We were at Taj Maha the other day and bought some mosquito coiks from Chedraui (mexican grocery) and they worked well.

 

[Manatee Diver]

You will sometimes get crap travelling with thermacells on planes. We were at Taj Maha the other day and bought some mosquito coiks from Chedraui (mexican grocery) and they worked well.

The new electric ones shouldn’t be too much of an issue. Just have to keep the cartridges in your checked bag, as they are liquid for the electric ones.

I have the Camp version that uses the same cloth mats, but you use a backpacking stove for fuel. Though it is useless for Tulum area as I don’t think I’ve found a camp store there.

 

[tridacna]

It may be better to avoid responding to questions with "Google is your friend" when your source is "my cousin told me..."

From a study published in the journal Current Biology in 2019:

Commonly used insect repellents hide human odors from Anopheles mosquitoes

The mode of action for most mosquito repellents is unknown. This is primarily due to the difficulty in monitoring how the mosquito olfactory system responds to repellent odors. Here, we used the Q-system of binary expression to enable activity-dependent ...

www.ncbi.nlm.nih.gov

From an earlier study, published in 2008 in PNAS:

From the Cover: Mosquitoes smell and avoid the insect repellent DEET

The insect repellent DEET is effective against a variety of medically important pests, but its mode of action still draws considerable debate. The widely accepted hypothesis that DEET interferes with the detection of lactic acid has been challenged by ...

www.ncbi.nlm.nih.gov

(Bolding mine.)

From your first paper: "These results suggest that synthetic repellents disruptively change the chemical profile of host scent signatures on the skin surface rendering humans invisible to Anopheles mosquitoes."

What exactly are you disagreeing with? My point is not to waste DEET spraying it on your clothing. Go ahead if you must.

 

[-JD-]

Guides were burning egg cartons which seemed to help.

WRT: DEET Why does the DEET need to be in direct skin contact? If the DEET is on the clothing, it should still act to mask the CO2 emitted from skin, since it will have to pass through the clothing to be detected by the mosquitos.

 

[tridacna]

Guides were burning egg cartons which seemed to help.

WRT: DEET Why does the DEET need to be in direct skin contact? If the DEET is on the clothing, it should still act to mask the CO2 emitted from skin, since it will have to pass through the clothing to be detected by the mosquitos.

See above citations. Full credit to @Esprise Me .

"These results suggest that synthetic repellents disruptively change the chemical profile of host scent signatures on the skin surface rendering humans invisible to Anopheles mosquitoes."