Why Do We Fall ill?

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4 Means of Spread and Principle of Prevention of Infectious Diseases

Some diseases are transmitted through some sources like contaminated food, water, and air. The chronic disease like AIDS is transmitted through blood transfusions, sexual intercourse, by sharing injection needles, even from mother to child by breastfeeding. A disease can either be air-borne or water-borne or food-borne based on transmitting agents.

1. Air-borne diseases

The transmission of these microbes occurs through the little droplets coughed out when an infected person sneezes or coughs.
Such disease-causing microbes are spread through air like, common cold, pneumonia and tuberculosis.

2. Water-borne disease

The transmission of these microbes occurs when the excreta of an infected person get mixed with the drinking water.
Such microbes affect a healthy person when he drinks this water like, Cholera.

3. Sexually-transmitted disease

These pathogens are transmitted by sexual contact from one partner to the other like, Syphilis and AIDS.

4. Spread of disease through vectors.

In this case, Vectors are carrier of the disease or infection.
For example, Mosquitoes (Anopheles) are vector of a disease, called malaria.

Differences between symptoms and signs

Symptoms	Signs
Symptoms indicate the presence of a disease.	Signs provide information about the presence of a particular disease.
They are a collective indication of a number of diseases in a particular part of organ.	They are distinct for different disease.

Principle of Treatment

Treatment is the method to deal with a disease once a person is infected but it has certain limitations.
Even after medication, infected person can serve as a source of infection.
Hence prevention is better than cure.
However, advanced technology has improvised the principle of treatment and prevention so that medicine for almost every disease is available now.
There are two ways to treat an infectious disease.
- Reduce the effects of the disease
- Kill the cause of the disease
The method of treatment based on the symptoms and signs are not an effective way of prevention. This is because the chance of recurrence is high.
Diseases that are caused either by bacteria or viruses or protozoa can be treated based on the types of agent and pathway, the pathogens follow to cause infection.