Why do We Fall Ill
· Health means a state of mental, physical, and social well-being.
· The health of an organism largely depends on his/her surroundings or the environment.
· Major causes of poor health are – the garbage, which is thrown in an open area nearby residence or streets, or/and the open drain water lying stagnant around the residence area.
· The public cleanliness is the key of good health.
· Some diseases, last only for a short period of time, are known as acute diseases. E.g. cold, fever, etc.
· The diseases that last for a long period of time, even as much as a lifetime, are known as chronic diseases. E.g. asthma, osteoporosis, etc.
· Chronic diseases, normally, have very severe long-term effects on people’s health as compared to the acute diseases.
· When microbes are the immediate causes of a disease, it is known as infectious diseases.
· Some of the major agents of infectious diseases are viruses, bacteria, fungi, and some single-celled animals (protozoans).
· Some diseases are caused by the multicellular organisms; such as worms.
· Kala-azar or black fever is caused by a protozoan parasite of genus Leishmania (shown in the image given below).
· Acne is caused by staphylococci bacteria (shown in the image given below).
· Sleeping sickness is caused by protozoan organism namely Trypanosoma (shown in the image given below).
Means of Spread
· Most of the microbial agents can commonly move from an affected person to other in number of ways.
· The microbial agents are ‘communicated,’ therefore, also known as communicable diseases.
· Some of the microbes can spread through the air; example of such airborne diseases are common cold, pneumonia, and tuberculosis.
· Some diseases can also be spread through water, known as waterborne diseases. E.g. cholera etc.
· Some diseases are transmitted by different animals including human beings; in fact, these animals carry the infecting agents. Therefore, such animals are intermediaries and known as ‘vectors’.
· Mosquitoes are the most common vectors.
· Infectious diseases can be prevented by means of public health hygiene measures.
· Infectious diseases can be prevented through proper immunization (in advance).