• Question: how many types of parasites are there?

    Asked by 649spar22 to Mark, Linda, Arporn Koi, Franco, Claire on 11 Jul 2016.
    • Photo: Linda Anagu

      Linda Anagu answered on 11 Jul 2016:

      Broadly we have ecto (live outside the body) and endoparasites (live inside the body), but there are numrous types 649par22.

    • Photo: Franco Falcone

      Franco Falcone answered on 11 Jul 2016:

      @649spar22, If you take the widest definition of ‘parasite’, which will include viruses as well, then there are more parasitic species than non-parasitic species, so I guess hundreds of millions or something like that. This is because parasitism is a very successful survival strategy.
      If you want to know how many of these can infect humans, and this is not counting viruses, I have read that there are about 300 species of worms and 70 protozoa which can infect humans, but I never spent time counting them.

    • Photo: Arporn Koi Wangwiwatsin

      Arporn Koi Wangwiwatsin answered on 11 Jul 2016:

      Hi 649,
      As Franco said, there are pleeeeenty of types of parasites. They might have evolved and become specialists to certain host, or become generalists and able to infect a wide range of hosts. And also many hosts can have more than 1 types of parasites.

      To help make sense of this huge variety, people have tried to group them by some criteria. THis can be, ecto- or endo- parasites depending on whether they live inside or outside bodies. Or it can be grouped based on their body shape and anatomy; for examples, parasitics worms can be grouped into round, fluke (they are flat-like-a-leaf type), or tapeworm. Then there are also parasites that are not worms and these are protozoa. They can also be grouped based on their structure as seen under a microscopes.

      There are a huge varieties and they used huge range of strategies to survive, and that’s what I like about parasites!