• Question: you can buy repellent for parasites what in the repellent deters them

    Asked by leo to Claire, Franco, Koi, Linda, Mark on 20 Jun 2016.
    • Photo: Franco Falcone

      Franco Falcone answered on 20 Jun 2016:

      @Leo yes you can buy repellents against mosquitos, sprays containing DEET, not sure how well they work, and whether mosquitos can adapt to them. There are also repellents against tick and fleas, these are used for pets (cats and dog) they are given through the skin and get into the blood, but they are not used in humans.The most popular is called Frontline, I have a box in my office. It protects against fleas, tick and lice, but as I said, they are not used in humans,just in pets. And what was the last time you had fleas, anyway?

    • Photo: Claire Bourke

      Claire Bourke answered on 20 Jun 2016:

      @Leo,
      you can indeed. For midges, which are biting insects that live in the UK and feed on human blood by biting through the skin, there is a very effective repellent called ‘Smidge’, which works by blocking the sensory receptors of the midges so that they find it harder to find somewhere to bite. Apparently this approach is more effective than the chemicals in DEET. I quite often visit the west coast of Scotland, which is famous for being plagued by lots of midges, and i always get fewer bites if I use Smidge!

      The best way to prevent insects from biting your skin is to cover up exposed skin by wearing long sleeves and there are also nets that can be put over beds, hats and tents that stop insects from coming too close. Even better, there are mosquito nets that are soaked in chemicals like DEET that stop them from getting to you and also kill the mosquito when they land on the net. Since mosquitoes can spread malaria-causing parasites, sleeping under one of these nets, or giving them out to communities at risk of infection, is an effective way to reduce malaria.

    • Photo: Mark Booth

      Mark Booth answered on 20 Jun 2016:

      Hi Leo

      Good question. Technically speaking mossies are not parasites because they don’t live on or in the animals from which they draw nutrients.

      Any parasite that penetrates the skin might be susceptible to a repellent. This type of parasite includes schistosomes and hookworms. A number of years ago there was a type of soap called Endod that was used topically to prevent the larvae of schistosoma penetrating the skin.

    • Photo: Arporn Wangwiwatsin

      Arporn Wangwiwatsin answered on 20 Jun 2016:

      Hi Leo,

      For parasites like ticks and fleas, you already got answer from Franco 🙂 . For mosquitoes (which is more like a vector of malaria parasites rather than being parasites themselves) the DEET is the main current line of repellent used.

      How the DEET work is not fully understood, but a couple of years ago researchers found that mosquitoes in the lab can become resistant to the DEET and no longer get repelled… although they are not sure if mosquitoes in the wild would do the same… nevertheless this suggest the need of on-going development for a new repellent.

Comments

  • Photo: Claire

    Claire commented on :

    Mark is right that the word ‘midge’ covers lots of species of biting insect and some aren’t considered to be parasites, even though the females feed on human and animal blood. Some however, including the black fly, are vectors or carriers of other parasites, such as the parasitic worm Onchocerca volvulus, but this doesn’t occur in the UK.

    Apparently smidge also works well for mosquitoes using the same mechanism of blocking their sensory receptors, but I haven’t tried it myself!