Types of Parasitism

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Types of Parasitism


Parasitism is a close association between two organisms of different species, of which one, called the parasite, obtains food, shelter from the body of other organism termed as its host. In this type of association the parasite is the gainer and the host is the loser. Host may be sometimes adversely affected by the parasite thus parasite limits the population of the host. The parasite is generally smaller than the host.Resolve all Your Biology Doubts from Physics Wallah.

I) Types of parasites

Parasites are classified into different categories on the basis of different criteria. Sometimes a single parasite may belong to more than one category.

  1. Ectoparasites

These are parasites which attach to skin, hair and any other surface of the host.

e.g. Pediculus humanus (louse), mites & leeches etc.

  1. Endoparasites

These are parasites which live within the body of host. Depending on where they live in the body of the host, endoparasites are of following types.

a) Coelozoic parasites

They live in the cavities within the body of the host. e.g. Trichomonas vaginalis, a flagellate parasite that lives in the vagina of women. Parasites such as the round worms and tape worms, which live in the cavity of the intestine of their hosts, are also distinguished as enterozoic parasites.

b) Histozoic parasites or Intercellular parasites

These are parasites which live between the cells in the tissues of the host. Entamoeba histolytica lives in the wall of the caecum and colon of the man, Wuchereria bancrofti lives in the lymph vessels and lymph glands of man are histozoic parasites.

c) Cytozoic parasites or Intracellular parasites

These are endoparasites which live within the cells of the host. Plasmodium (malarial parasite) that lives with in the cells of the liver and in the red blood cells of man at different stages during its life history, Leishmania donovani that lives in the reticulo-endothelial cells of man are cytozoic parasites.

  1. Obligate parasites

These are organisms which can live only as parasites and cannot live independently. Moreover some obligate parasites can live only in a specific host.

e.g. – Adult Taenia solium can live in the intestine of the human host and not in other mammals.

  1. Facultative parasites

These are those parasites which can live independently if host is not available.

e.g. – Mycobacterium tuberculosis, which causes tuberculosis in man.

  1. Hyperparasites

These are animals which live as parasites on the parasites of other animals.

e.g. – Nosema notabilis (a cnidosporan) is a hyperparasite of Sphaerospora polymorpha (another cnidosporan) that lives as a parasite in the urinary bladder of the toad fish.

  1. Pathogenic parasites

Those parasites which cause disease in the host are called pathogenic.

e.g. – Plasmodium, Leishmania, Taenia species, Ascaris, Wuchereria etc.

  1. Non pathogenic parasites

These are parasites which do not cause any disease in the host.

e.g. – Trichomonas hominis found in human intestine.

Entamoeba gingivalis in the gums of humans.

  1. Temporary or intermittent parasites

These parasites are not constantly associated with the host but they obtain nourishment from the host time to time.

e.g. – female mosquitoes, bed bugs and leeches etc.

  1. Monogenetic parasites

These parasites complete their life cycle in only a single host.

e.g. – Ancylostoma duodenale, parasite of intestine of man etc.

  1. Digenetic parasites

These parasites complete their life cycle in two hosts.

e.g. – Fasciola hepatica completes its life cycle in sheep and snail. Taenia solium completes its life cycle in man and pig.

Types of Parasitism Pdf

Types of Parasitism

Types of Parasitism

Types of Parasitism

Types of Parasitism

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