Infectious diseases can spread to health people in the flowing ways.

Through direct or indirect contact

Diseases like, measles, chickenpox and fungal infections can spread through direct contact with an infected person. They also spread through indirect contact, that is, by touching things which an infected person may have had contact with. Many other diseases, like tuberculosis, infection by worms, viral fevers and the common cold, also spread through indirect contact. The germs pass from infected persons to the articles handled by them such as towels, coins, currency notes, door and bus handles, utensils, clothes, handkerchiefs and sheets. The eggs of worms and germs causing intestinal diseases spread through the articles touched by an infected person if he does not wash his hands properly after visiting the toilet.

Diseases Trough air

Some bacterial and viral diseases of the respiratory tract are transmitted through the air. Some germs of influenza and tuberculosis, for example, pass into the air from the nose, throat and lungs of an infected person when he coughs, sneezes, talks or breathes.

Through water

A person can get infected by diseases like hepatitis, typhoid, cholera and dysentery by drinking contaminated water or using such water to wash utensils, and so on. Contaminated water may also carry the eggs and larvae of worms.

Water bodies often get contaminated by faeces washed off the ground by rain water. They may also get contaminated if people use them for bathing and washing, and if untreated sewage is discharged into them. Through the water supplied in towns a city is usually treated for purification, it is often not processed properly.

Through food

Many intestinal diseases spread through vegetables and fruit washed with contaminated water. They may also spread trough UN hygienically prepared cold drinks, ice creams, and so on. Meat which is not processed or cooked properly carries the larvae of worms. Food poisoning, through to communicable as such, is caused by food infected by fungi or bacteria. Food which is not processed or canned properly or which is stored UN hygienically or left uncovered can cause food poisoning. So, can stale food UN pasteurized milk.

Through vectors

Flies and cockroaches carry germs from garbage and sewage and deposit them on food. They spread the germs of diseases like typhoid, dysentery and cholera. Rat fleas carry the germs of plague from rats to human beings. Lice and ticks are some other vectors.

Through bites

Rabies is carried by animals which are infected by the virus. It is transmitted to human beings and other animals through the bite of an infected animal. This deadly disease is carried by dogs, cats, monkeys and raccoons.

The bites of some other animals are very harmful and may be fatal. The venom of some snakes, like cobras and adders, damages the nervous system and treatment must be sought immediately to prevent death. Certain scorpions too are poisonous, and a person who has been stung should be treated immediately.

Prevention of diseases

The following measures can be taken to prevent the occurrence and spread of communicable diseases

a) Drinking water must either be boiled or adequately purified wit the help of a filter. It should be stored in a clean container with a cover.

b) One must not eat which has been lying exposed. Food should be covered to prevent contamination by flies and cockroaches. Food poisoning can also be prevented by avoiding stale food.

c) Vegetables and Fruit should be washed with clean water before they are eaten.

d) It is essential to wash one’s hands with soap before eating or handling food and after visiting the toilet.

e) People suffering from a communicable disease should take simple precautions to prevent the disease from spreading. These including using a handkerchief to blow one’s nose and taking care not o spit in public places. Soiled clothes and the utensils used by the patient should not be washed near a source of drinking water. In the case of diseases like chickenpox, the patient should be kept in isolation.

f) One should maintain personal hygiene, and not share articles of personal use.

g) One must keep one’s surroundings clean. This includes proper disposal of waste, keeping drains clean and not allowing water to stagnate in coolers and pools.

h) Immunization is a very important step, which we shall discuss in detail later.