WHY DO WE FALL ILL

IMPORTANT TERMS

Health: - According to the World Health Organisation (WHO), health is a state of complete physical, mental and social well-being and not merely an absence of disease or infirmity.

Disease: - Any deviation from normal functioning or state of complete physical, mental or social well-being is called disease.

Immunisation: - Immunisation is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine.

Vaccine: - Preparation of weakened infectious agents or their products that can be injected or given orally to prevent specific disease.

Symptoms: - A symptom is a departure from normal function or feeling which is noticed by a patient, reflecting the presence of an unusual state, or of a disease.

Sign: - A sign is an objective indication of presence of a particular disease, which the physicians will look for on the basis of the symptoms.

Vector: - A vector is an organism that does not cause disease by itself but which spreads infection by conveying pathogens from one host to another.

Host: - An organism that is infected with or is fed upon by a parasitic or pathogenic organism (for example, a virus, nematode, fungus).

Antibiotics: - Antibiotics, also called antibacterials, are a type of antimicrobial drug used in the treatment and prevention of bacterial infections.

 

TYPES OF DISEASES

1. Acute Diseases: - Diseases which last for very short period of time are called acute diseases. Since it is over very soon, it does not have time to cause major effects on general health. Eg. Common cold, fever.

2. Chronic Diseases: - Diseases which last for a long time, even as much as a life time are called chronic diseases. Eg. Tuberculosis, cancer.

3. Congenital Diseases: - These diseases are present since birth. They are caused due to genetic abnormality or due to metabolic disorders or malfunctioning of any organ. Eg. Colour blindness.

4. Acquired diseases: - These diseases are those which develop after birth. Acquired diseases can be classified into two types:

 

a. Infectious or communicable diseases

Diseases which can be transmitted from one individual to another directly or indirectly are called communicable or infectious diseases. These diseases are caused by some biological agents or pathogens such as virus, bacteria, fungi etc. Examples of such disease are tuberculosis, cholera etc.

b. Non-infectious or non-communicable diseases.

Diseases which cannot be transmitted from one individual to another directly or indirectly are called non-communicable or non-infectious diseases. These diseases are restricted only to those persons who are suffering from them. For example, scurvy, cancer etc.

INFECTIOUS AGENTS

The infectious agents mainly fall into four categories:

Bacteria: - Typhoid fever, Cholera, Tuberculosis, Anthrax

Viruses: - Common cold, Influenza, Dengue Fever, AIDS

Protozoan Microbes: - Malaria, Kala-azar

Fungi: - Skin infections

Disease	Causative agent
Typhoid Fever	Salmonella typhimurium
Cholera	Vibrio cholerae
Tuberculosis	Mycobacterium tuberculosis
Anthrax	Bacillus anthracis
AIDS	HIV (human immunodeficiency virus)
Malaria	Plasmodium species
Kala-Tzar	Leishmania
Acne	Staphylococcus bacteria
Sleeping sickness	Trypanosoma

 

 

MEANS OF SPREADING DISEASES

Air borne	Water borne	Sexually transmitted	Vector borne
Transmitted through air when droplets of pathogens are expelled into the air due to coughing, sneezing or talking.	Waterborne diseases are caused by pathogenic microorganisms that most commonly are transmitted in contaminated fresh water. Infection commonly results during bathing, washing, drinking, in the preparation of food, or the consumption of food that is infected.	Transmitted through sexual contact. Also spread through blood to blood contact with infected people, or from an infected mother to her baby during pregnancy or through breast feeding.	Vector-borne diseases are illnesses that are transmitted by vectors, which include mosquitoes, ticks, and fleas.
Most likely to be spread in overcrowded or poorly ventilated housing.	Most likely to spread in absence of safe supplies of drinking water.	Not spread by casual physical contact.	These vectors can carry infective pathogens such as viruses, bacteria, and protozoa, which can be transferred from one host (carrier) to another.
Chickenpox, Influenza, Measles, Smallpox, Cryptococcosis, and Tuberculosis.	Typhoid, cholera and Hepatitis A	Syphilis, AIDS	Malaria, Dengue Fever

 

CONDITIONS NECESSARY FOR GOOD HEALTH

• Public cleanliness by providing good sewage and rain water disposal systems and    proper garbage disposals
• Availability of safe and clean drinking water
• Availability of adequate, nutritious food
• Social equality and harmony
• Good economic conditions and jobs

 

IMPORTANT POINTS TO REMEMBER

1. ‘Symptoms’ of disease are the things that we feel as being wrong. These indicate that there may be a disease but don’t indicate what the disease is whereas ‘Signs’ of disease are what physicians will look for on the basis of the symptoms. It will give a more definite indication of presence of a particular disease.
2. Antibiotics like Penicillin are used to treat bacterial infections as these block the bacterial processes that build the cell wall. Viruses do not have these biochemical pathways like bacteria and that is the reason why antibiotics do not work against viral infections.
3. Human cell lacks cell wall, so Penicillin has no effect on us.
4. Categories of infectious agents are important to decide what kind of treatment is required.
5. If microbes enter the body from the air via nose, they are likely to affect the lungs.
6. If microbes enter the body through mouth, they can stay in the gut lining like typhoid causing bacteria or they can go to the liver, like the viruses that cause jaundice.

 

INTERESTING FACTS

• For many years, everybody used to think that peptic ulcer is caused due to a stressful life which led to a lot of acid secretion in the stomach. Barry Marshall and Warren showed that patients could be cured of peptic ulcer only when the bacteria Helicobacter pylori were killed off from the stomach.
• Cow is ‘vacca’ in Latin and cowpox is ‘vaccinia’. From these roots, the word ‘vaccination’ has come into our usage.
• Hereditary is one unavoidable factor that can cause some lifelong and fatal illnesses. For instance, diabetes, breast cancer.
• Living cell is a dynamic place. Something or the other is always happening. Cells move from place to place. Even in cells that do not move, there is a continuous repair going on.
• When you fall asleep while overthinking, the mind remains active as if you were awake, which is why you tend to wake up tired.
• A mother who falls sick can usually continue to breastfeed. Breast milk does not transmit illness to the baby. Instead, the antibodies produced by the mother’s body to combat the illness pass to the baby and help prevent baby from getting sick.