• Question: which parasite has the most powerful bite?

    Asked by Nikkita to Claire on 15 Jun 2016.
    • Photo: Claire Bourke

      Claire Bourke answered on 15 Jun 2016:

      Thanks for your question Nikkita. The strength of a bite is difficult to quantify and compare between different species of parasite, but there are many parasites that bite. Of the insect parasites mosquitos, sandflies and black flies can all be itchy and sore, but the pain caused by the bite is perhaps less dangerous than their potential to infect the person who is bitten with other diseases. For example mosquito bites can transmit malaria parasites, sandflies can transmit another single-celled parasite called Leishmania and black flies can transmit a parasitic worm species called Onchocerca volvulus. So maybe its not the power of the bite, but how dangerous it can be that we need to think about?! Other parasites that bite us include ticks and fleas and some worms also bite, such as hookworm, which latch onto the lining of the gut to feed on blood of infected people…ouch!

      Another thing to think about is that sometimes the cleverest parasites are the ones that can bite but that we can’t feel. For example, mosquitos bite people so that they can feed on their blood and if their bite is very obvious then the person might notice and kill them or swat them away which means they don’t get as much blood; a better strategey is to bite in a less obvious way (or at night when people are sleeping) so that the mosquito gets to feed for longer. So again, powerful may not always be best when it comes to parasites.

Comments

  • Photo: Franco

    Franco commented on :

    @Nikkita
    Blood-feeding insects can be divided into two groups, the ‘capillary’ feeders and ‘pool’ feeders. Insects like mosquitos are capillary feeders, they insert a tube- or needle-like structure into the host’s skin until they find a capillary. This is usually not associated with pain. Pool feeders, like blackflies, sandflies, tsetse flies, or ticks are less subtle in their approach. With their sharp mouthparts, they cut a hole into the skin and feed on the blood flowing into the wound (they create a pool of blood, that’s why they are called like that). This is far more painful for the host. The exception is the tick: although ticks are also pool feeders, they inject substances which block pain (called analgesics) into the skin, and substances which keep the blood flowing (called anticoagulants), mainly because ticks feed for up to 24-48 hours, so if they caused pain they would be too likely to be detected and removed by the host (for example by biting off or scratching).

    So in both cases it’s not so much a bite, in the first type of feeding it’s more like a needle and syringe (capillary feeders), while in the second case (pool feeders) it is more like cutting a hole into the skin. So although as Claire said it is a bit difficult to measure and compare, I would say that pool feeders have probably the more powerful bite, certainly the more painful bite*! (*ticks excepted)

  • Photo: Linda

    Linda commented on :

    Well scripted Claire but @Nkkita, take note, the mosquitoes, sand flies and black flies are vectors that carry this parasite and unintentionally pass the parasite to man when they bite. Parasite themselves do not bite, their vector or carrier does.