HUMAN AND MICROBIAL INTERACTION

1. HUMAN AND MICROBIAL INTERACTION Dr. Gemza Shah

2. NATURE OF INTERACTION BETWEEN MICROBES AND HUMAN • Transient microbiota may be present for days, weeks, or months • Normal microbiota permanently colonize the host.

3. HUMAN GIT SHOWING NORMAL FUNCTIONS OF NON PATHOGENIC MICROBES

4. TYPES OF INTERACTION BETWEEN HUMANS AND MICROBES • Commensalism- Microbes that do not help or harm us are commensals. • Example: Most of the normal flora in the body. • Mutualism- Microbes and host benefit • Example: A microbe producing vitamins in the intestine • Parasitism-Microbe benefits and harms the host • Example: Pathogens • Opportunistic Pathogen-Normally harmless organism becomes pathogenic in a compromised host

5. COMMENSALISM • Commensalism is a class of relationship between two organisms where one organism benefits but the other is neutral (there is no harm or benefit). 

6. COMMENSALISM • One of the best examples would be the relationship between cattle egret and cows and sheep (or cattle). The cattle egret is called so because it is often seen with cattle and livestock. Whenever horses, cows and other such livestock graze in fields, they tend to stir up and move many insects that have been resting on the grass. The cattle egret then catches them and preys upon them. The cattle egrets benefit from this because they manage to get the insects that they wish to prey on whereas the cattle remains unaffected.

7. MUTUALISM • Mutualism is a positive reciprocal relationship between two species. Through this relationship both species enhance their survival, growth or fitness. To a certain extent the relationship is more a reciprocal exploitation rather than a cooperative effort on the part of the individuals involved. • Its simply the living together of two organisms in a mutually beneficial relationship. .

8. PARASITISM • A form of symbiosis in which one organism (called parasite) benefits at the expense of another organism usually of different species (called host). The association may also lead to the injury of the host. • Ectoparasites live on the body surface of the host; endoparasites live in their hosts' organs, tissues, or cells and often rely on a third organism (the carrier, or vector) to transmit them to the host. 

9. PARASITISM • The organism that benefits in a parasitic relationship is called the parasite. • The organism that is harmed in a parasitic relationship is called the host.

10. COMMON PARASITES

11. PARASITE-TAENIA SAGINATA • Taeniasaginata, also known as the beef tapeworm, is a parasite of both cattle and humans, causing taeniasis in humans. • Taeniasaginata occurs where cattle are raised by infected humans maintaining poor hygiene, human feces are improperly disposed of, meat inspection programs are poor, and where meat is eaten without proper cooking.

12. TAENIA WORM I HUMAN EYE PARASITISM

13. REASONS FOR WHICH PATHOGENS ENTER INTO HUMAN BODY Pathogenic bacteria enter through: • Cuts • Contaminated food or water • Close contact with an infected person • Contact with the faeces of an infected person • Breathing in the exhaled droplets when an infected person coughs or sneezes • Indirectly, by touching contaminated surfaces – such as taps, toilet handles, toys and nappies.

14. STEPS TO INFECTION

15. PREDISPOSING FACTORS OF THE HOST Make the body more susceptible to disease • Short urethra in females • Inherited traits such as the sickle-cell gene • Climate and weather • Fatigue • Age • Lifestyle • Chemotherapy

16. BENEFICIAL EFFECTS OF MICROBES Production of FoodsMicrobes are a key component in both home and industrial food preparation. Lactic acid bacteria are used to make yogurt, cheese, sour cream, buttermilk and other fermented milk products. Vinegars are produced by bacterial acetic acid fermentation. Yeast is used in the manufacture of beer and wine and for the leavening of breads. It is also involved in fermentations to convert corn and other vegetable carbohydrates.

17. BENEFICIAL EFFECTS OF MICROBES Medical, Pharmaceutical and Biotechnological ApplicationsCertain microbes can help us in the fight against other microbes. In human and veterinary medicine, that are used to  treat and prevent infectious diseases, microbes are a source of antibiotics and vaccines. Microbes and Humans The microbes that normally live in association with humans on the various surfaces of the body (called the normal flora), such as Lactobacillus and Bifidobacterium, are known to protect their hosts from infections and otherwise promote nutrition and health

18. HARMFUL EFFECTS OF MICROBES • The harmful effects of microbes include diseases, destruction of crops, food items. • Micro-organisms, especially molds, can trigger respiratory infections and allergies if they grow in our workplaces or homes. • The parasitic worm infestations can result in iron deficiency anaemia • The round worms, hookworms and round worms result in growth retardation in children.

19. INFECTIONS BY PATHOGENS • The normal flora of the human body can be disturbed in cases of nutritional deficiencies due to which the immune/defense systems of the body become weak. • As the immunity falls low the human body falls a prey to the pathogenic microbes • The intake of excessive antibiotics or strong chemotherapeutic drugs can also cause an imbalance between the pathogenic and non pathogenic microbes hence resulting in infections.

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