DISCUSSION OF PYQ (5:05 PM):

Consider the following: 1. Bacteria 2. Fungi 3. Virus Which of the above can be cultured in an artificial/ synthetic medium? (Prelims 2021) a) 1 and 2 only b) 2 and 3 only c) 1 and 3 only d) 1,2 and 3 Answer: A

Approach:

• Artificial/Synthetic medium means non-living/non-organic medium
• As we know viruses cannot survive without a living host, so viruses cannot be grown in artificial medium.
• But viruses can still be grown in a laboratory if a proper living medium is provided.

Revision of the previous classes:

Congenital disease:

• It is any abnormality in the structure or function of a person that is present right from the time of birth.
• For example- Congenital heart disease, cleft lip, etc.

Acquired disease:

• Any disease which was not present at the time of birth, but developed at a later stage of the life of an organism.

Two types of acquired diseases:

Communicable/ Infectious diseases:

• These diseases are caused by disease-causing organisms called pathogens.

Non- Communicable/ Non Infectious diseases:

• They are not caused by pathogens but by lifestyle or environmental factors.
• For example, hypertension, depression, etc.

Communicable diseases are of two types:

• Contagious diseases: Diseases that spread through direct contact.
• For example Covid-19.
• Non-contagious: Those communicable diseases which don’t spread through direct contact, but through other methods.
• For example- Malaria, Polio, etc.

Vector:

• A vector is an organism that does not cause the disease but spreads the infection by taking pathogens from one organism to the other.

Bacteria:

• It belongs to the Monera classification.
• They are unicellular & prokaryotic.
• Some important bacterial diseases are Tuberculosis, Whooping cough (pertussis), cholera, Pneumonia, tetanus, etc.

Tuberculosis:

• It is a very common disease all over the world.
• Elimination of TB is included under the Sustainable Development Goals.
• It is caused by the pathogen Mycobacterium tuberculosis.
• It mainly affects the lungs- Pulmonary Tuberculosis.
• Other parts of the body can also be affected by Tuberculosis as the Brain, Intestines, Bones, etc. and it is called Extra Pulmonary Tuberculosis.
• TB is a fully treatable disease.

Some symptoms of Pulmonary Tuberculosis:

• Persistent cough for more than two weeks/15 days.
• Afternoon rise of body temperature, due to the life cycle of bacteria.
• Extreme and quick weight loss.
• Blood in the sputum.

Antibiotics:

• Antibiotics are the drug against bacteria.
• They are prescribed along with a detailed drug routine which will have information about the dosage, frequency, and duration of intake.

ANTIBIOTIC RESISTANCE (5:30 PM):

• It is the acquired ability of germs like bacteria and fungi to defeat the drugs that were designed to kill the germs.
• Antibiotic resistance is included in Antimicrobial resistance.
• It is the ability of a microorganism like bacteria or virus which stop an antibiotic, antiviral, or anti-fungal from working against it.
• It can be developed naturally or by misuse of drug therapies like self-medication, animal-based foods over-exposure to antibiotics, etc.
• This condition makes standard treatment ineffective, the infection persists and may spread to others.
• Once any bacteria acquires anti-biotic resistance against a specific drug, the drug will not work on the bacteria regardless of the quantity.
• Acquiring antibiotic resistance is an irreversible phenomenon. 
• It can happen naturally or through misuse of drug routines.
• Under-treatments become ineffective, infections persist and can spread to others.

Which of the following are the reasons for the occurrence of multi-drug resistance in microbial pathogens in India? (Prelims 2019) 1. Genetic predisposition for some people 2. Taking incorrect doses of antibiotics to cure diseases 3. Using antibiotics in livestock farming 4. Multiple chronic diseases in some people. Select the correct answer using the code given: (a) 1 and 2 only (b) 2 and 3 only (c) 1,3 and 4 only (d) 2,3 and 4 only Answer: B Approach: The first statement is not correct because multi-drug resistance can only happen after prolonged exposure to many drugs, and it is not genetically transferred. The fourth statement is not correct as the drugs for different diseases caused by different microorganisms do not have many effects on different micro-organisms.

Acute diseases	Chronic diseases
They are diseases that are of short duration.	They are diseases that are of longer duration.
They are of higher severity.	They are of lower severity.
For example- Cancer, Arthritis, etc.	For example Common Cold, Flu, etc.

VIRAL DISEASES (6:00 PM):

• Some examples include polio, AIDS, dengue, chikungunya, etc.
• We have no anti-viral medicine as such for most viral medicines.
• For most viral diseases, we mainly try to cure the symptoms of the disease rather than the disease, as we saw with COVID-19.

Healthcare:

• Healthcare services are of two types- Preventive and Curative.
• Preventive healthcare includes vaccines, a good lifestyle, awareness, etc.
• Curative healthcare includes giving medicines, surgery, etc.
• Preventive healthcare must be prioritized because steps for preventive healthcare are relatively cheaper and will include the entire population.

Hepatitis:

• Hepatic refers to the liver.
• The liver sees inflammation, swelling, loss of function,m increase in temperature, etc.
• It is caused by the pathogen hepatitis virus.
• The five major types of hepatitis are Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, and Hepatitis E.
• Hepatitis B and C have the highest mortality.
• Hepatitis C has no vaccine.
• Jaundice is a symptom of the liver not functioning properly, under Hepatitis A.

Zika Virus:

• The biological vector is the Aedes mosquito.
• It can also be communicated through body fluids, mother-child transmission, etc.
• It has a symptom of microcephaly an abnormally small head.
• 

• Strategy to prepare for diseases: We must focus only on the diseases that have been in the news. Cause Mode of transmission. Related national schemes. Symptoms. Diagnosis Treatment We must not cover them in detail, but a basic idea would be enough. The span and depth as mentioned in the India Year Book would be enough.

Nipah Virus:

• Symptoms include fever, vomiting, respiratory issues, and inflammation in the brain.
• It is carried mainly by fruit bats, but can also infect domestic animals such as pigs, along with humans.
• It spreads through contact with bodily fluids from infected animals or people

IMMUNITY (6:45 PM):

• Immunity is the balanced state of an organism having adequate defense to fight any unwanted agents.
• Immunity can be both innate & acquired/adaptive.

Innate Immunity:

• It is the non-specific immune response that is activated immediately forming the first line of defence of the individual.
• Here "non-specific" means that innate immunity acts against all kinds of microorganisms.

It includes:

• Physical barriers like skin, mucus membranes, etc.
• Chemical barriers as they are present in saliva, tears, stomach hydrochloric acid, etc.
• Cellular defense like white blood cells ( neutrophils, monocytes, etc.)

Acquired/ Adaptive immunity:

• It is the specific immune response developed against an unwanted agent by exposure of the immune system to it.
• it is slower than innate immunity.

Lymphocytes:

• They are a type of white blood cells.
• Two types of lymphocytes are B cells and T cells.
• T cells later go to the Thymus gland in the neck for getting mature.
• Except for T cells, all other blood cell formation starts from the bone marrow itself.

Antigen-Antibody:

• An Antigen is an entity that causes the body to initiate an immune response.
• An Antibody is a protein produced in response to certain antigens to destroy the antigens.
• The relation between antigen-antibody is similar to lock-key, as we see only specific antibodies in response to specific antigens.
• B cells produce antibodies and their response is called anti-body mediated response.
• Antigen can be any entity but antibodies will always be proteins.

PHAGOCYTOSIS (7:15 PM):

• It is the process by which a cell uses its plasma membrane to engulf a large particle and then break it down.
• T cells use this mechanism to provide cell-mediated immune response.

Immunological memory:

• When the B cells encounter the antigen for the first time, they produce antibodies against it.
• When the B cells( or body) encounter the antigen again, they remember the earlier experience.
• This recall of the antibody response is called immunological or immune memory.
• So we see cases in which once someone gets a disease cured, he/she will never suffer the disease again as commonly seen with chicken pox.
• The immune memory is different for different persons and diseases.
• This is why some people get seasonal diseases many times.

Vaccination:

• Vaccination is a process whereby a person is made immune or resistant to a particular disease by stimulating his own immune system.
• When the body encounters an antigen for the first time, a slow and low-intensity production of antibodies happens.
• The B lymphocytes however remain sensitized and immunological memory is created.
• On subsequent attacks by the same antigen, this memory gets triggered and a fast and high-intensity immune response is generated.
• This provides protection against the antigen.
• Vaccination's aim is to produce a memory of the disease (to trigger an immune response) without making the person experience the disease.

Types of vaccines:

I. Live attenuated vaccine:

• The pathogen is alive but weakened so that it does not cause the disease but retains its capacity to grow.
• For example- the Oral Polio vaccine, and BCG vaccine.

II. Inactivated killed vaccine:

• The pathogen is killed but certain parts of its structure are still able to create an immune response.
• For example- injectable polio vaccine, India-made covid vaccine, etc.

III. Sub-Unit vaccine:

• It uses specific parts of a protein that can act as a pathogen to trigger an immune response.
• For example- for whooping cough.

IV. Conjugate vaccine:

• It uses two specific parts of a pathogen like a protein and a polysaccharide together.
• For example- The pneumococcal conjugate vaccine.

NCERTS for self-study:

• Class 8, Chapter 2
• Class 12, Chapter 8

The topics for the next class are active and passive immunity.