PARASITES:HABITAT AND ENVIRONMENT

By:

AHMED SARWAR Master in scienceAssam University, Silchar

INTRODUCTION

“A parasite is an organism that sustains itself by living on or within another organism and obtains nutrients from that host organism”

__ Matt Slick”Organ system evolved especially those containing cavity or

surfaces presented a habit for potential parasites.In vertebrates;a. The alimentary canal and its associated glandsb. The blood streamc. The respiratory system , etc.

THE ALIMENTARY CANAL

The mouth , oesophagus and stomach are not common habits for parasites .

Trematodes and Copepodos (Amphibian mouth parasites) Trichonaonas buccalis (Man mouth parasites)

Stomach contains nematode , Haemonchus contortus and larvae of bot flies.

Most sites for intestinal parasites are :Duodenum , ileum , caecum and large intestine.

Contd..

GENERAL ENVIRONMENTAL CONDITIONSDUODENUM This region is highly rich in nutrients , foods. The anterior duodenum is a region of comparative calm, and

is favourable. ILEUM Down the small intestine; the availability of food materials

for intestinal parasites decreases due to the absorption of amino acids and carbohydrates.

There is another source of nutrients availability is cell of intestine itself.

Contd..

GENERAL ENVIRONMENTAL CONDITIONSCOLON AND CAECUM These are the region of comparatively inactive and most of the

intestinal parasites are found in these zones.LIVER Protozoans and several helminthis are the main parasites found in the

liver. Not stable for its chemical compositions. Rich in growth factors such as iron, vitamins, and plasma proteins. For stored materials favourable in or near liver to the parasites.

The blood stream

GENERAL ENVIRONMENTAL CONDITIONS

BLOOD The soluble food materials varies with feeding habit of the

host. A cystoid; without having gut and is dependent on the small

food molecules such as amino acids, glucose, etc. Its comparatively poor medium than duodenum. In Schistoma having boyh gut and well developed digestive

enzyme system they gets high nutritional value by feeding protein in plasma and blood cells.

TISSUE AND OTHER MUSCLE:GENERAL ENVIRONMENTAL CONDITIONS This environment is liable to change suddenly. It contains high degree of ATP and components such as

myoglobin, myosin, actin etc. The most studied parasites of skeletal muscle are probably

the Sarcocystis and the incysted stage of Nimatode.

Physico-Chemical characteristics of environment

In the parasitic environment the major physico-Chemical parameters includes:

pH Oxygen Oxidation-reduction potential.

pH: The hydrogen ion concentration alters sharply from region to region .In mammals ,pH of mouth is about 6.7,but it shows a range of 5.6-7.6.In stomach strongly acidic conditions prevail but their degree of acidity varies remarkably with the condition of animal.

Contd...

Oxygen: The oxygen tension 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.

Oxidation-reduction potential: It has importance to the electron transport of parasites. Reducting condition of oxidation-reduction potential

serves as a signal to trigger many hatching stages in parasitic life cycle.

CONCLUSION

For parasites the host is the total environment. Larval and other reproductive stages may live in the world for longer or shorter periods but this represents merely a necessary phase in the movement from the host to host.

The environment is wholly biotic in origin , as it is provided by a living organism, it is still possible to define each niche by what are essentially abiotic factors such as pH , oxygen tension, redox potential and nutrient availability, as well as truly biotic factors such as other parasites and resident micro organisms.

REFERENCES

Chadwick,V.S & Phillips, S.F 1982 small intestine. London Cheng,T.C 1976, liver and other digestive organs;in

ecological aspects of parasitology(ed. C.R Kennedy) pp.287-302

Kennedy,C.R.1978. ecological aspects of parasitology.NY M.V.K Sukhdo,Lesilieh.Chapel-1994

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