IMMUNITY & IMMUNISATION

 

IMMUNITY & IMMUNISATION

    

Microbes vs Pathogen:

·        Microbes are simple microorganisms - unicellular or multicellular

·        Pathogens are disease causing microbes

o   Bacteria, Fungus, Virus, Protozoa

·        Prokaryotes and Eukaryotes

·        Bacteriophage: Virus infecting Bacteria

·        Retrovirus

o   goes against the Central Dogma of Life (DNA => RNA => Protein)

o   RNA has genetic material

o   Can undergo Reverse Transcription

Antigen:     

·        Substance that is capable of stimulating an immune response (to produce an antibody).

o   surface proteins, antibody generation

·        Self antigens (auto-antigens) and Foreign antigens(hetero-antigens)

·        Antigens are targeted by antibodies.

o   Each antibody (immune response) is specifically produced by the immune system to match an antigen after cells in the immune system come into contact with it; this allows a precise identification or matching of the antigen and the initiation of a tailored response.

Antibodies:

·        Generated by WBCs, antigen specific

Immunity:

·        Innate

o   non-specific, immediate, since birth

·        Acquired

o   Develops over lifetime

o   Strong and specific during 2nd attack

o   Lymphocytes(specialised WBCs) involved:

§  Humoral Immunity

§  B-Cell - release antibodies in the blood

§  Cell mediated immunity [Rejection of organs while transplantation]

§  T-Cells

§  Killer cells - attack pathogen directly

§  Helper cells - signal both B-Cell and Killer cells

§  Suppressor T-cells - calm down the Killer cells 

·        Active

o   Self immunity - WBCs

o   Long term

·        Passive

o   Injecting Antibodies from outside

o   Short term

o   eg. Colostrum

 

NOTE:

·        HIV directly attacks T-cells

·        T-cells have involvement of Thymus gland

·        B-cell - 1st found in Bursa of birds

 

Vaccination

·        Activated lymphocytpes(memory cells) - Primary and Secondary Immune Response

·        Zoonoses - Animal to Human transmission

·        Forms

o   Live Attenuated

§  Stronger Humoral and Cell Mediated Immunity

§  Vaccine Derived Infection in Immunodeficient individual

§  eg. Oral Polio Vaccine ( Sabin Vaccine )

o   Killed/Inactivated

§  Safer, weaker immunity

§  Inactivated Polio Vaccine ( Salk Vaccine )

§  Cholera Vaccine 

o   Recombinant Vaccines

§  rDNA Technology to add antigen of pathogen on the DNA using genetic engineering

§  Hepatitis-B and Influenza vaccines

·        Herd Immunity

o   Increase protection for non-vaccinated individuals by increasing the barrier against spread of infection

o   Vital role in global eradication of Small Pox and aiding in Polio also.

Mission Indradhanush

 

·        Universal Immunisation programme

o   Launched in 1985 to provide vaccination against life threatening diseases

o   Stagnated recently with only 65% coverage and 1% annual growth

o   Revamped as Mission Indradhanush in 2014 

·        Goal: Full immunisation with all available vaccines for children upto 2 years and pregnant women

·        Initially

o   7 vaccine preventable diseases

o   Target: 90% coverage by 2020

·        Accelerated to 5% annual coverage

·        Revised:

o   New vaccines added

o   Target preponed to December 2018

 

·        Coverage:

o   Bacteria

1.    Diptheria

2.    Pertusis or Whooping Cough

3.    Tetanus

4.    Hepatitis-B

5.    TB

6.    Haemophilus Influenzae Type B or Pneumonia

7.    Pneumococcal diseases

o   Viral

1.    Polio - Both OPV and IPV

2.    Measles

3.    Rubella

4.    Rotavirus

5.    Japanese Enchepalitis

6.    Diarrhoea

Anti Microbial Resistance

 

What:

·        Resistance development against antimicrobial medicines to which they were sensitive earlier

·        DR genes passed onto next generation - superbugs

 

How:

·        Mutation in the pathogen upon contact with the Anti microbial drug

 

Impact:

·        Infections do not respond to standard line of treatment

·        Prolonged illness

·        Increased cost of treatment

·        Increasing death rate

Why:

·        Unregulated OTC sale of Antibiotics w/o prescription

·        Unregulated use of veterinary medicines

·        Mixing of drugs in food and fodder for growth of animals - cow, chicken, pork etc

·        Dumping of Pharma waste leading to frequent exposure

·        Even actions like bathing in Ganga have led to AMR

 The Mission Indradhanush, depicting seven colours of the rainbow, will aim to cover all those children by 2020 who had not been vaccinated, or were partially vaccinated, against seven vaccine-preventable diseases — diphtheria, whooping cough, tetanus, polio, tuberculosis, measles and hepatitis B.

Under Universal Immunization program, Children were given vaccine for Polio, Measels, Childhood TB, Hepatitis B, Tetanus, Diphtheria, Pertussis (whooping cough)

 Although organisms such as bacteria function as parasites, the usage of the term "parasitic disease" is usually more restricted. The three main types of organisms causing these conditions are protozoa (causing protozoan infection), helminths (helminthiasis), and ectoparasites

Dracunculiasis, also called guinea worm disease (Parasite or worm), Yaws (Bacteria), Small Pox (virus) already eradicated from India

Acute flaccid paralysis (AFP): Polio is a disease caused by a virus. But AFP can also arise for other reasons, including infection by non-polio pathogens. the country’s polio surveillance system has indicated a sharp increase during recent years in the number of non-polio AFP cases. 

A pentavalent vaccine is five individual vaccines conjugated in one intended to actively protect infant children from 5 potentially deadly diseases: Haemophilus Influenza type B (the bacteria that causes meningitis, pneumonia and otitis), Whooping Cough (or Pertussis), Tetanus, Hepatitis B and Diphtheria