Classification of Protozoan Parasites – Parasites

by Vincent Racaniello, PhD

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    00:01 So protozoan parasites can be further classified in a variety of ways. There can be amoebas for example.

    00:10 Here is an example of an ameoba parasite that causes disease of humans This happens to be Entamoeba histolytica. Amoeba of course move by extending pseudopods and streaming their cytoplasm in the direction of the pseudopod.

    00:28 Entamoebas are protozoan parasites that are amoebas. They alternate between trophozoites which are in the form in the host and the cyst form which is in the environment.

    00:39 So again, a nice way of enabling passage of the entamoeba from host to host, the passage occurs via the cyst and the trophozoite grows in the host. So that's Entamoeba histolytica.

    00:52 Another classification of these protozoan parasites is as flagellates.

    00:57 Some of them have flagella that enable them to move in fluids. An example of this is Giardia shown in this picture.

    01:06 Typically, the protozoan parasites, that in fact, the intestinal tract, that are flagellated alternate between trophozoite and cyst forms.

    01:19 But there's another category of this flagellated protozoan parasites that infect the blood.

    01:25 Those are transmitted by arthropods. So these are Trypanosomes in the blood.

    01:30 They don't alternate between two forms as do the intestinal protozoan parasites.

    01:36 These rather have one form but they're transmitted by arthropods so that protects them outside of the host.

    01:42 Then we have the ciliates. There are many ciliated protozoans but only one of them is a human parasite.

    01:51 And that's shown here in this photograph, it's in the phylum Ciliophora and it's called Balantidium coli.

    02:00 So this is the only ciliated protozoan parasite known to cause disease in people.

    02:08 As I said there are many many other ciliated parasites but they are harmless.

    02:12 This photo is actually quite nice because you can see the tiny cilia around the entire organism and these are constantly in motion and they enable the organism to move.

    02:24 And lastly, we hava category of what we call apicomplexans. This is based on a morphological feature of this protozoan parasite.

    02:34 And the epidemy of apicomplexan parasites are the Plasmodium species which cause malarias.

    02:41 And these are characterized by intracellular replication.

    About the Lecture

    The lecture Classification of Protozoan Parasites – Parasites by Vincent Racaniello, PhD is from the course Microbiology: Introduction.

    Included Quiz Questions

    1. It is transmitted through an arthropod vector
    2. It moves using pseudopods
    3. It is an amoeba
    4. It alternates between trophozoite and cyst form
    1. Balantidium coli
    2. Entamoeba histolytica
    3. Trypanosoma
    4. Giardia
    5. Plasmodium

    Author of lecture Classification of Protozoan Parasites – Parasites

     Vincent Racaniello, PhD

    Vincent Racaniello, PhD

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    By AESOOK B. on 10. August 2020 for Classification of Protozoan Parasites – Parasites

    the tone of voice and eye contact good just like in a classroom