PARASITIC EFFECTS ON HOSTS


EFFECTS OF PARASITES ON HOSTS

parasitic castration-2 paracastration-4 neoplasia -4 neoplasia-5 neoplasia-3 neoplasia-2neoplasia-1 liver of a sheep infected by fasciola liver fluke in liver

In general, the parasites cause weakening of the body of their hosts by causing the deprivation of nutrients, fluids and metabolites as they compete with their hosts for the same. They may also cause pathological effects in their hosts such as

  1. Parasitic castration,300px-Fasciola_hepatica
  2. Hypertrophy,
  3. Hyperplasia
  4. Neoplasia,
  5. Gigantism,
  6. Pathogenic effects.

1. HYPERTROPHY-Some parasites cause an abnormal increase in the volume/size of the infected host cells. This kind of parasitic effect is called hypertrophy.of sheep

e.g.  Hypertrophy is exhibited by RBC’s that are infected by plasmodium.

hypertrophy-hyperplasiais.jpg hypertrophy in RBCF._hepatica_hypertrophia_of_bile_duct

hypertrophh1

2. HYPERPLASIA-`Some parasites cause an abnormal increase in the number of cells . This kind of parasitic effect is called hyperplasia.

e.g.,  Fasciola hepatica causes the thickening of bile ducts in the sheep by stimulating  cell division.

3. NEOPLASIA-Some parasites cause an abnormal growth in the host cells in a tissue to form new structures. This kind of parasitic effect is called Neoplasia.

e.g.,  Hyperplasia caused by some viruses in man leads to cancer.fasciola in bile duct of sheep

4. GIGANTISM-Some parasites cause an abnormal increase in the size of the host. This kind of parasitic effect is called Gigantism.

e.g., The larval stages of Fasciola hepatica cause gigantism in snail, an intermediate host.

5. PARASITIC  CASTRATION-Some parasites cause the degeneration of gonads of the host, making it sterile. This effect is called Parasitic castration.

e.g., Sacculina (root headed barnacle, a crustacean), which lives as an ectoparasite on crab(Carcinus maenas) causes the degeneration of gonads of the ovaries in it.

6. PATHOGENIC EFFECTS-Most of the parasites cause various types of diseases like

A. Malaria by Plasmodium sps,

B. Amoebiasis by Entamoeba histolytica,

C. Elephantiasis by Wuchereria bancrofti,

D. African sleeping sickness by Trypanosoma gambiense,

E. Delhi boils/Taskent ulsers/ Oriental sores by Leishmania    tropica,

F.  Kala azar/ Dum dum fever/ Visceral leishmanniasis by Leishmania donovani,

paracastration-4casration-3

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About balarangaiahnarapuram

TEACHER M.Sc in ZOOLOGY M.Sc in PSYCHOLOGY B.Ed
This entry was posted in BIOLOGY IN HUMAN WELFARE and tagged , , , , . Bookmark the permalink.

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