This week I was given a rather interesting thought experiment: to take something that we spend most of our day in or around, and design it in some way that addresses a specific one health problem. So I chose clothing; we think about it all the time, but also don’t think about it. Obviously, we wear it all the time, so we could use it to help in multiple ways. Since several of my previous blogs discussed diseases caused or spread by ticks, fleas or mites, I will specifically focus on that.

Many dog owners use topical flea and tick preventative. It’s very convenient: just put a few drops of a liquid on the pet’s back, comb it through, and for 30 days you don’t have to worry about a flea infestation or any nasty diseases from a tick. Has anyone ever considered applying it to people, especially people in areas where neglected tropical diseases run rampant? If clothing could be laced with products to repel or kill pests, many infestations could be prevented or reduced in severity.

The main ingredient for the topical flea and tick preventative Frontline is methoprene, a chemical that mimics the juvenile insect hormone. This hormone is present before insects molt to the adult stage, and they cannot finish their development so long as it is around. With Frontline, it is used to prevent fleas from being able to complete their life cycle and establish an infestation on a dog. Humans and dogs have no receptors for the compound, so it has little to no effects on us even if we drink or inhale it.[1] It has a faint, fruity smell and no taste, and so is not repulsive to people. As such, this chemical has been added to drinking water to control mosquitos that carry malaria, and used in the production of many food products to prevent spoilage due to insects.[2]

An ingredient for another popular preventative—Advantage Multi—is moxidectin, a drug that kills parasites by disrupting nerve transmission and causing paralysis. It was found safe enough to be used en masse in Africa to prevent infection by a parasitic worm that causes blindness in people.[3] Combined on clothing with a similar chemical called imidacloprid, it could also control mite infestations.

There are, of course several obstacles to utilizing such a method of control. The first and biggest is the long-term development of resistance, a subject I have previously spoken of.[4] Allowing parasites to constantly come into contact with these chemicals will naturally select for some few who can survive, and allow them to rapidly spread their resistance among the population.

Next is the practical problem of manufacturing clothing with these compounds mixed in. Everyone who uses topical flea and tick preventative on their pet knows it must be reapplied regularly. And if the pet gets bathed too often, or takes too many trips into the swimming pool or pond, there is a risk of washing the protection off. Having to reapply the compound to clothing every month or two defeats the purpose of such a measure.

But even allowing for solutions to these difficulties, clothing is not incredibly cheap to manufacture even on its own, and adding insecticide compounds would likely increase the cost. It would be difficult to develop a cost-effective method to be able to produce and distribute clothing to areas of need, and then would require help from anthropologists to make sure the people knew why they had to wear the clothes.

Perhaps an easier medium would be an ankle bracelet similar to the Seresto flea collars used for dogs and cats. If a bracelet would slowly release the insecticide and last for 8 months like the pet product does, it could be a more viable option for distribution. However, it could pose a risk for waste build-up and environmental effects if the bracelets were simply discarded in a trash heap once they no longer provided enough protection for the wearer.

More study and development would have to go into this idea to be able to solve its other problems, most notably the risk of resistance. But if used as part of a multimodal one health approach, it could be one useful piece of the control plan.

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[1] https://nepis.epa.gov/Exe/ZyNET.exe/P100MT2M.txt?ZyActionD=ZyDocument&Client=EPA&Index=1991%20Thru%201994&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&UseQField=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A%5CZYFILES%5CINDEX%20DATA%5C91THRU94%5CTXT%5C00000031%5CP100MT2M.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h%7C-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r75g8/r75g8/x150y150g16/i425&Display=hpfr&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results%20page&MaximumPages=1&ZyEntry=2

[2] https://nepis.epa.gov/Exe/ZyNET.exe/P100MT2M.TXT?ZyActionD=ZyDocument&Client=EPA&Index=1991+Thru+1994&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A%5Czyfiles%5CIndex%20Data%5C91thru94%5CTxt%5C00000031%5CP100MT2M.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h%7C-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r75g8/r75g8/x150y150g16/i425&Display=hpfr&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results%20page&MaximumPages=1&ZyEntry=1&SeekPage=x&ZyPURL

[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4072596/

[4] https://vetmedone.health.blog/2019/02/11/its-the-resistance/