Lecture 13

Any malfunctioning process which interferes with the normal functioning of the body is called a disease

A. Congenital disease (Innate) B. Acquired disease

The disease which is present from birth (e.g. hole in the heart in infants).

They are caused by some genetic abnormality or metabolic disorder or malfunctioning of an organ.

The diseases which may occur after birth during one’s lifetime.

(i) Infectious diseases: (ii) Degenerative diseases: iii) Deficiency diseases: (iv) Cancer

The diseases which can be transmitted from diseased healthy person to e.g. measles.

The diseases caused by the malfunction of some vital organs of the body e.g. heart failure.

These are caused due to nutritional deficiency such as that of minerals or vitamins in the diet e.g. anaemia(Fe), Beri- beri (Vitamin B)

This is an abnormal, uncontrolled and unwanted growth of cells. e.g. breast cancer.

(i) Communicable diseases. ii) Non-communicable diseases.

The diseases which can be transmitted from an infected person to a healthy person.

These diseases do not spread from an affected person to a healthy person.

1)direct transmission 2)indirect transmission

1) Direct contact between the infected person and the healthy person: 2) Droplet infection 3) Contact with soil 4) Animal bite

Diseases like small pox, chicken pox, syphilis spread through direct contact.

The infected person throws out tiny droplets of mucus by coughing, sneezing or spitting. These droplets may contain the pathogen. By inhaling the air containing the droplets, a healthy person may get the infection. Diseases like common cold, pneumonia, influenza, measles, tuberculosis and whooping cough spread through droplet infection.

contaminated with disease-causing viruses and bacteria.

Viruses of rabies are introduced through the wound caused by the bite of rabid animals, especially dogs. The virus is present in the saliva of the rabid animals.

1) By vectors such as houseflies, mosquitoes, and cockroaches. 2) Air-borne 3) Object borne 4) Water borne:

The pathogens of certain diseases reach the human body through some intermediate agents.

Examples: Houseflies carry the causative organisms of cholera on their legs and mouth parts from the faeces and sputum of infected persons to food and drinks and contaminate them. When this contaminated food is taken by a healthy person, he gets the infection. Similarly, mosquitoes carry virus of dengue and malarial parasite which causes malaria.

pathogens may reach humans with air and dust.

Many diseases are transmitted through the use of contaminated articles, such as clothes, utensils, toys, door handles, taps, syringes and surgical instruments