Parasite Habit and environment.pptxxxxxc
- 1. A Presentation on: Parasites: habitat and environment Submitted to Dr. Meenakshi Bawari Associate Professor Dept. of Life Science and Bioinformatics Assam University,Silchar Submitted by Sanghamitra Das Roll no: 15 M.Sc 3rd Semester Dept. of Life Science and Bioinformatics Assam University, Silchar
- 2. Introduction What are Parasites? An organism living in or within another organism in order to obtain nutrients, grow or multiply often in a state that directly or indirectly harms the host. In other words parasites are those organisms which survive at the cost of their host. For example: Fasciola hepatica
- 3. Habitat of parasites: Definition of Habitat: A habitat is a place where an organism meets all the environmental conditions an organism needs to survive. Most favourable habitat for a Parasite: Organs system evolved especially those containing cavity or surfaces present the most favourable habitat for a parasite. InVertebrates: a. The alimentary canal and its associated glands. b. The blood stream c. The respiratory system
- 4. The Alimentary canal: Mouth , Oesophagus and stomach are less common habitat for parasites. Exceptions: a.Trichomonas buccalis ( Man mouth parasite) b. Haemonchus contortus ( Cattle stomach parasite) Most favourable site for parasites are: Duodenum , Ileum, Caecum and Large intestine.
- 5. GENERAL ENVIRONMENTAL CONDITIONS: DUODENUM: This region is rich in high nutrient food materials and is thus favourable for the parasites. ILEUM : Down the small intestine; the availability of food materials for intestinal parasites decreases due to absorption of amino acids and carbohydrates But there is another source of nutrient availability and these are the cells of intestine itself.
- 6. GENERAL ENVIRONMENTAL CONDITIONS COLON AND CAECUM: The caecum is a special favourable site for parasites such as Entamoeba . This is a site of comparative inactivity. In herbivores the caecum is the site where cellulose digestion takes place, a process aided by bacterial action. LIVER: Protozoans and several helminths are the main parasites found in liver. For example: Fasciola hepatica The hepatic tissues are rich in factors such as iron, vitamins, and plasma proteins. The liver tissues are also rich in stored food materials which are available for uptake by the parasites.
- 7. GENERAL ENVIRONMENTAL CONDITIONS BLOOD In blood the soluble food materials varies with the feeding habit of the host. A Cestode , which lacks gut is completely depended on the small food molecules of absorbable dimensions such as amino acids, glucose, etc. Schistosoma mansoni ( blood fluke) possesses both a gut and a well- developed digestive enzymes , they get high nutritional value by feeding on the protein present in plasma and blood cells. Fig: Schistosoma mansoni Fig: Snail with Schistomiasis
- 8. GENERAL ENVIRONMENTAL CONDITIONS: MUSCLE TISSUE : Muscle is not generally favoured site for parasites. This is probably related to the nature of its function, which results in an environment which is liable to change suddenly. The muscle tissues are rich in ATP and components such as myoglobin, myosin, actin , etc. The most studied parasites of skeletal muscle are probably the protozoan Sarcocystis and the encysted stage of the nematode Trichinella spiralis . Fig: A muscle affected by Sarcocyst
- 9. PHYSICO-CHEMICAL PARAMETERS OF PARASITIC ENVIRONMENT In parasitic environment the major physico-chemical parameters include: pH Oxygen concentration Oxidation-reduction potential ( Redox potential) pH: The hydrogen ion concentration alters sharply from region to region. In mammals , pH of mouth is 6.7. In stomach strongly acidic conditions prevail but their degree of acidity varies remarkably with the condition of animal
- 10. Contd… Oxygen concentration: The oxygen concentration is of special interest in relation to possible aerobic or anaerobic metabolism of intestinal parasites. It also effects greatly the nutritional state and level of host. Oxygen-reduction potential: It is of importance in the electron transport of parasites. Reducing conditions serve as a signal to trigger many hatching stages in parasite life cycle, such as hatching of coccidian oocysts, trematode cysts, nematode eggs.
- 11. CONCLUSION For parasites the host is their total environment. The environment is wholly biotic in origin, as it is provided by living organisms.
- 12. REFERENCES Chadwick, V.S & Philips, S.F 1982 small intestine. London Kennedy, 1978, Ecological aspects of Parasitology,NY Links:httpsP://books.google.co.in/books? isbn=0521428114
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