Microbes and Disease: Meaning, Diseases Caused by Microorganisms

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Meaning of Microbes and Diseases

  • Microbes are those microorganisms that are minute, unicellular and cannot be seen with naked eyes.

  • The harmful microorganisms are called pathogens.

  • Useful microorganisms prevent the growth of harmful bacteria.

  • A few useful microorganisms are bacteria, fungi, and protozoa.

Uses of Microorganisms

  • Food Industry and Beverages.

  • They help in processing and preservation of food.

  • Microorganisms help in enhancement of soil fertility and cleaning.

  • In the pharmaceutical industry, antibiotics are injected into the body and the body learns to fight off the diseases. For e.g. mumps and the measles.


  • Microflora is the aggregate collection of microorganisms present in the human body.

  • Bacteria live in a symbiotic relationship with the humans.

  • Microflora produces vitamin K crucial for blood clotting.

  • The invasion of the foreign bodies is also prevented by acting against the deadly microbes.

Four Sites of Entrance of Microbes in Human Body

Four sites of entrance of microbes in human body

Four Sites of Entrance of Microbes in Human Body

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Respiratory Tract (Mouth and Nose)

Example is influenza virus which causes the flu.

Gastrointestinal Tract (Mouth Oral Cavity)

Example is Vibrio cholera which causes cholera.

Urogenital Tract

Example is Escherichia coli which causes cystitis.

Breaks in the Skin Surface

Example is tetanus caused by Clostridium tetani.

Microbes Cause Illness

  • They reach their target site in the body.

  • Get attached to the target site they are trying to infect.

  • They multiply rapidly.

  • Nutrients are obtained from the host.

  • Avoid and survive attack by the host’s immune system.

Infectious Disease and the Microbes

Infectious disease and the microbes

Infectious disease

Microbes causing disease

Type of microbe


Varicella zoster





German measles




Mycobacterium tuberculosis


Bubonic plague

Yersinia pestis


Whooping cough

Bordetella pertussis



Trichophyton rubrum


Athletes’ foot

Trichophyton mentagrophytes



Plasmodium falciparum


Microbe Awareness

  • Keeping immunization up to date.

  • Preparing and handling food carefully.

  • Using antibiotics only for infections caused by bacteria.

  • In case of rapidly worsening infection the doctor should be reported.

  • Staying alert to disease threats.

  • Healthy habits need to be endorsed such as eating well, getting enough sleep, exercising, and avoiding tobacco and illegal drug use.


Q. What are the seven types into which Microorganisms can be divided?


Microorganisms can be divided into seven types namely bacteria, archaea, protozoa, algae, fungi, viruses, and multicellular animal parasites (helminths).

Q. What are the four different sites through which microbes can enter a human body?


The four different sites through which microbes can enter a human body are:

i) Respiratory tract

ii) Urogenital tract

iii) Gastrointestinal tract

iv) Skin surface

Q. What are the types of microbes involved in infectious diseases Chickenpox, Ringworm, Athletes’ foot, and Malaria?


Infectious disease and Type of microbe

Infectious disease Type of microbe

Chickenpox Virus

Ringworm Fungus

Athletes’ foot Fungus

Malaria Protozoan