Human Diseases


The diseases can be simply defined as a disturbance in the normal functioning of the body, among which few affects only to the particular organ system and some affect the entire body of an organism. There are numerous diseases which vary in their signs, symptoms, and causes. Pathology is the branch of medicines which mainly deals with the study of disease, the nature of diseases, its cure, diagnosis, etc.

Let us study certain communicable human diseases along with its causes and preventions.

Communicable disease

Common Diseases

A disease, which spreads from one person to another person, is termed as the communicable disease. It is also referred as infectious diseases or transmissible diseases.

Causes of communicable disease

The agents causing communicable diseases include Virus, Bacteria, protozoa, and Fungi.



These microbes are small infectious agents which are present in food, air and in the water. They penetrate very easily into our body through the mouth, nose, cuts, injuries, scratches on the skin from the environment (from the soil, water, and air) and other infectious agents and causes severe infections which may also lead to the person’s death. The viral infections can be easily transmitted from person to person.

AIDS, Polio, Measles, Influenza are a few examples of infections caused by a virus.



There are millions and billions of beneficial and harmful bacteria present all around us. Few among them are present both inside and outside our body always, by protecting our body from the disease-causing microbes. These bacteria are called as beneficial bacteria. The other group of bacteria, cause harm by entering into our body. These bacteria generally, engulf, reproduce kill the protective bacteria and cause harm to the host cells by releasing toxins. Tuberculosis, Whooping cough, Typhoid, Cholera, are few examples of infections caused by bacteria.



They are single-celled, microscopic, eukaryotic organisms. Malaria and other immune system disorders are few examples of infections caused by the protozoan.



They are threadlike parasites, which cannot synthesize their food and feeds on other organic material in which they live in. Ringworm, Athlete’s foot are a few examples of infections caused by fungi.

There are other agents, who act as a carrier or vectors and they carry the disease-causing microorganisms and spread from one person to another person. These vectors include mosquitoes, rats, house flies, etc.

Control and Prevention of communicable disease

Listed below are few precautions, which should be carried to avoid infection and other spreading diseases.

  • Drink only boiled and filtered water.
  • Maintain a proper hygiene in a food which we eat.
  • Maintain cleanliness around us.
  • Keep our body clean and tidy by having the regular bath.
  • Wear clean and ironed clothes.
  • Avoid the entry of vectors like mosquitoes, rats, house flies, cockroaches by spraying insecticides.
  • Disinfectants and other antiseptics can be used to destroy the microbes.
  • Fish plays a vital role in destroying mosquitoes and their larvae by eating them. So by introducing fish aquarium in our home, we can prevent mosquitoes from transmitting diseases.

There are many diseases which develop from the environmental problems, through nutrition deficiency, blood-related issues, chromosomal disorders, and so on.

To know more information about the different human disease along with its symptoms, diagnosis, treatment, visit BYJU’S.

Practise This Question

From the pictures given below identify why there are so many varities in butterflies and chillies?