Introduction
The condition of body to function physically, socially and mentally well is called its health.
A body with good physical and mental condition we call it a healthy body. It is not just a body free from disease or weakness but a state of thorough physical, mental and social well-being.
A particular abnormal condition or function affecting the part or the entire organism is called a disease.
A body infected with a disease is called a diseased body.
Causes of diseases
Diseases are caused as result of following reasons:
- Lack of nutritious and sufficient food.
- Unhealthy and dirty surroundings.
- Contact with an infected person.
- Using the personal belongings of an infected person.
- Eating untreated water and food from an unclean and unhygienic place.
- Lack of hygienic practices.
Acute disease
The diseases that persist for only a short period of time are called acute diseases. For example, cough, cold, fever, etc.
As acute diseases lasts for a short period of time it doesnot get enough time to cause any fatal effects to the general health.
Chronic disease
The diseases that persist for a longer period of time or even lifetime are called chronic diseases. For example, elephantiasis, cholesterol, heart attack, cancer, emphysema bronchitis.
Fig. Elephantiasis
Due to its longevity chronic diseases imparts major effects on the general heath of a person suffering from chronic disease.
Infectious disease
The diseases caused due to the infections spread by microbes such as bacteria, virus, fungi, etc. are called infectious diseases.
For example, chicken pox, AIDS, dengue, fever, cold are caused by virus.
Fig. Chicken Pox
Typhoid, cholera, tuberculosis are caused by bacteria.
Malaria, kala azar are caused by protozoa.
These diseases are spread by the microbes.
They can be transferred from an infected person to a healthy by several means. Therefore, infectious diseases are also called communicable diseases.
Non-infectious Diseases
The diseases that are caused by the means other than microbes are called non-infectious diseases.
They are mainly caused by internal means like personla hygiene, environmental factors, genetic disorder, etc.
For example, cancer, diabates, heart disease, stroke, chronic lung disease, etc.
Fig. Person suffering from heart attack
As they are not caused by microbes therefore they do not spread from an infected person to a healthy person through any means. Therefore, they are also called non-communicable diseases.
Modes of transmission of disease
The diseases that spreads from an infected person to a healthy and disease free person are called communicable diseases.
These diseases spreads when an infected person sneezes or coughs, they throw tiny droplets of water into the air that contains the microbes of the infection.
A healthy person standing nearby when inhale the air they take in the infected air and may fall sick.
Some example of communicable diseases are chicken pox, tuberculosis, Pneumonia, etc.
These diseases also spreads when the excreta of an infected person somehow gets mixed with drinking water used by other people to drink.
Diseases like cholera, typhoid spreads through this means and cause disease to a new host.
Communicable diseases also spread through sexual intercourse between an infected person and a healthy person.
Therefore, diseases like Acquired Immune Deficiency Syndrome (HIV/AIDS), syphilis are sexually transmitted diseases (STDs).
Acquired Immune Deficiency Syndrome (HIV/AIDS) can also spread through other means like blood-to-blood contact with an infected person by using same syringes in hospitals, or using same personal belongings (for example, razor, toothbrush, etc.).
Acquired immune deficiency syndrome (HIV/AIDS) can also spread to a healthy baby from their mother during pregnancy or by breast feeding.
Some diseases like skin infections, ringworm, conjuvitis are spread by direct contact with infected person through handshakes, touch or kiss.
Many diseases are carried from an infected person to a healthy person through animals. Such animals are called vectors.
Mosquitoes and houseflies are good examples of such vectors.
The female anopheles mosquito spreads Malaria whereas Female Aedes mosquito spreads Dengue.
Houseflies sits on garbage, drains, human and animal excreta and then flies off and sits on uncovered food consumed by healthy person. This way houseflues transmits the disease to the new healthy host.
How to prevent the spread of diseases
Spread of diseases from an infected host to a healthy host can be prevented to a great extent if are aware of certain points and follow certain hygienic practices.
We can prevent airborne diseases by avoiding exposure to overcrowded areas, using masks to cover nose and mouth while going out.
We can prevent water borne diseases by making water free from germs by boiling them, using disinfectants like chlorine to kill the microbes in water, using proper water filtration equipments available in markets.
We can prevent vector borne diseases by preventing the growth of vectors in our surroundings. This can be done by keeping our surrounding clean, cleaning stagnant water (in potholes, coolers, pots, tyres or beakers), covering the drains and garbage bins, practising proper garbage disposal habits, etc.
Avoid using public toilets.
Avoid drinking water and food from unhygienic and dirty places.
Always wash hands thoroughly before eating food.
Avoid using others’ personal belongings.
Manitain proper hyigienic habits.
Avoid using the same syringe used to inject previous patients, blades or razors used to shave previous customers in salon.
How to treat diseases
The two ways to treat diseases are to reduce the effects of diseases and to inhibit the growth or kill the disease causing microbes.
In order to reduce the effects of the disease take medicines to reduce pain and fever to some extent accompanied with adequate rest to conserve energy.
Each kind of disease causing microbes like virus, bacteria, fungi, protozoa have their separate and unique biochemical life processes. The life processes of one organism are not shared by other organism.
The bacterial infections can be cured by using antibiotics.
Antibiotics are the medicines that inhibits the growth or kills the bacteria cauisng microbes by blocking the pathway for bacterial synthesis but doesnot affect its own pathway.
The antibiotics block the biochemical processes used by bacteria to build cell wall that protects them. Consequently, the growing bacteria cannot make cell walls and dies at the end.
But viruses on the other hand have very less biochemical life processes of their own and hence uses our mechanisms for their life processes that results in lesser number of virus specific targets to hit by the antibiotics. Therefore, antibiotics cannot cure viral diseases or infections. But still there are many anti-viral drugs available in the market.
Specialised cells called immune cells in human body fights off disease causing microbes and kills them everytime such microbes enter the body.
If the specialised cells kills the microbes then we don’t fall sick.
Availablity of proper, sufficient and nutritious food is necessary to stay healthy.
If a body suffers from a particular disease once then there are lesser chances of suffering from it again because when a bodysuffers from an infectious disease for the first time it fights against it and kills it.
The the immune cells win the fight then we are disease free or else we fall sick.
The cells remembers how to respond to that specific disease due to which when the body encounters from the same disease next time, it responds to it with increased vigour. This helps to eliminate the infection at a greater speed.
Vaccination
Vaccine is a biological preparation that resembles a disease causing microbe.
Vaccination is the process in which vaccine is given to improve the immunity of the body against a specific disease. Vaccination are available for diseases like tetanus, diptheria, whooping cough, measles, polio, chicken pox, etc.
The microbe injected into the body through vaccination is a dead or a weak microbe and hence does not affect the body. Therefore the immune system is able to manage.
But at the same time the immune syatem also recognizes the microbe and the ways to fight it back.
When the same microbe comes to affect the body next time then the immune system recognizes it and fights back thereby prevents us from getting sick.
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