Disease causing Microorganisms in Humans – Notes Class 8

Disease-causing microorganisms can be of different types such as bacteria, fungi, viruses, protozoa, etc. These microorganisms enter the body of humans, plants, and animals who become the host for them. They rely on the host for nutrition. Inside the body of living things, these microorganisms target particular types of cells and inhibit their normal functioning. They start to multiply inside the human body and affect multiple cells which leads to diseases in them.

What are Microbes?

Organisms that cannot be seen through the naked eye but only through a microscope are termed microorganisms. Humans, plants, and animals suffer from various diseases in their life. Microorganisms can be single-celled as well as multicellular and can be both harmful and useful to humans. Many organisms cause diseases in humans. These microorganisms may enter the body of humans directly or through some carriers such as mosquitoes, flies, etc. For example, Dengue and malaria are spread by the virus carried by mosquitoes. Microorganisms are present almost everywhere in the world, from mountains to deep oceans and from the hot Sahara Desert to areas with temperatures below freezing point. We shall briefly discuss the uses of microorganisms and look at disease-causing microorganisms in detail.

Microbes and Diseases

As we discussed, various microorganisms are harmful to humans and cause various diseases in humans. These microorganisms are called pathogens and come in contact with humans through environmental factors such as air, water, and food. They may also travel from one person to another through direct or indirect contact. Diseases that travel through contact from an infected person to a healthy person are called communicable diseases. Examples common cold, TB, Hepatitis, etc. Let us look at the diseases caused by various microorganisms.

Disease Caused by Microorganisms

Disease	Microorganism
Tuberculosis	Bacteria
Typhoid	Bacteria
Cholera	Bacteria
Plague	Bacteria
Tetanus	Bacteria
Ringworm	Fungi
Athlete’s Foot	Fungi
Malaria	Protozoa
Sleeping Sickness	Protozoa
Dysentery	Protozoa
Wart	Virus
Common Cold	Virus
HIV	Virus
Ebola	Virus
Covid	Virus

Apart from these microorganisms also cause diseases in plants as well as animals. Some of these diseases are:

Diseases Caused by Microorganisms in Animals

Disease	Microorganism
Foot and Mouth disease	Bacteria
Anthrax (In both humans and plants)	Virus

Diseases Caused by Microorganisms in Plants

Disease	Microorganism	Transmission Mode
Citrus canker	Bacteria	Air
Yellow vein mosaic of Bhindi (Okra)	Virus	Insect
Rust of wheat	Fungi	Air, Seeds

Apart from causing disease, microorganisms like fungi cause spoilage of food by growing on the surface of food. The fungi multiply very quickly on the food with time. If this spoilt food is consumed, it may cause food poisoning and may sometimes even lead to death. To avoid spoilage of food, various preservation techniques such as pickling, dehydration, etc. are used.

FAQs on Disease causing Microorganisms in Humans

Q1: Name some diseases caused by microorganisms in plants.

Answer:

Diseases such as yellow vein mosaic and rust of wheat are caused by microorganisms in plants.

Q2: How pickling helps in preserving food?

Answer:

The process of pickling uses salt and oil. The use of salt removes moisture from the food and prevents the growth of microorganisms and oil cuts off the supply of fresh oxygen to the food item which helps to preserve the food.

Q3: What is pasteurization?

Answer:

The process of boiling milk at a high temperature for some time and then immediately cooling it is known as pasteurization.

Q4: Which microorganism causes TB? Which part of the body is affected in the disease?

Answer:

TB or Tuberculosis is caused by bacteria. This disease affects the lungs and the respiratory system in humans and can also prove fatal.