Harmful Micro-organisms

IMYP1 Bio Term 2 Week 1

1. HARMFUL MICROORGANISMS W e previously learnt that there are organisms that are extremely small and can’t be viewed without the help of a microscope. T hese organisms are called microorganisms. some of them are quite helpful but some are harmful, they cause diseases.

2. Harmful microorganisms can spoil our food, leather, clothing etc. One another harmful effect of microorganisms is that they cause diseases in plants, animals and even human beings. Microorganisms include bacteria, algae, fungi, archaea, and protozoa . Harmful microorganisms which cause disease are known as infectious agents.  These are harmful in nature and are also called pathogens .

3. 1) Pathogens can mostly cause communicable diseases.        •  Communicable diseases are the diseases which are transmitted from one person to another by different modes of infection. Body fluids of the infectious person carry disease causing organisms. e.g. Discharge from nose, mouth, eyes and the faeces carry these pathogens. Healthy person coming in contact with such infected discharges develops the disease and becomes sick.

4. 2) Pathogens select carriers to reach their particular host. Insects, rodents, sometimes even sheep, pigs and many other animals become carriers for pathogens to reach their final host . 3) Pathogens can be microorganisms which obtain nourishment from the host. e.g. Bacteria, Viruses, Fungi, Protozoa, Helminths.

5. Harmful effects of microorganisms Microorganisms show many harmful effects on us . Some of the effects are clarified below. Except for genetic and congenital factors, most of the diseases are caused by certain microorganisms.

6. Harmful microorganisms not only damage the human body, but also the food we eat. Sometimes , they multiply on food and release toxic products, hence cause food poisoning. To avoid food poisoning, food preservation is done in various ways like pasteurization, salting, boiling etc .

7. Modes of infection Infection is the transmission of pathogens from diseased individual to healthy individual.

8. Common diseases in human beings

9. Prevention of infection We can prevent the spread of infection by using a handkerchief while sneezing or coughing. Antibiotics are widely used to control the infection. Antibiotics are used to cure a variety of diseases caused by fungi, bacteria and protozoa . Infection can be prevented by using some bacteria or fungi which produce specific chemicals to prevent the growth of microbes causing disease . Diseases can be prevented by vaccination. Vaccination is the process of administering vaccines.