Health care

Healthcare, Infectious, Non-infectious, and Genetic Diseases form an important part of Science and Technology, as they help us understand how diseases arise, spread, and can be prevented or treated. This topic also covers diseases caused by deficiencies, various syndromes, zoonotic and non-zoonotic diseases, eye-related disorders, and diseases spread by mosquitoes and flies, highlighting the role of the immune system in protection. Additionally, the study of drugs and their classification explains how different medicines act to prevent, control, and cure diseases, contributing to better healthcare and quality of life.

Healthcare: infectious, non-infectious, and genetic diseases

When the functioning of one or more organs or systems of the body is adversely affected, characterized by the appearance of various signs and symptoms, we say that we are not healthy, i.e., we have a disease. 

A wide range of organisms belonging to bacteria, viruses, fungi, protozoans, helminths, etc., could cause diseases in humans. Such disease-causing organisms are called pathogens. Most parasites are therefore pathogens as they cause harm to the host by living in (or on) them.

Diseases have two broad categories: Congenital and Acquired diseases. 

• Congenital Diseases –These are structural or functional abnormalities. These diseases are present in a person since birth. Congenital diseases are genetic disorders (e.g., sickle cell anemia), disorders related to physiology and development (e.g. hair lip or cleft lip).
• Acquired diseases – These diseases are caused by various reasons after birth i.e., infection, disruption, diet, addiction, stress, mutation etc. Acquired diseases are further divided into two types: Infectious disease and Non infectious disease

Non-infectious diseases

Non-infectious Diseases – Factors other than pathogens(Like lifestyle, environment, or aging) cause these diseases. These can’t be spread by contact from one person to another. Thus also known as non-communicable diseases. For these reasons, they are connected to each person, e.g., Cancer, allergy, deficiency diseases, injuries, etc. These may be of various types –

1. Deficiency Diseases – It is caused due to less availability of any essential component of diet or unbalanced diet. For example, kwashiorkor, blood impairment (deficiency), and beriberi.
2. Degenerative Diseases – These diseases are caused due to weakness or old age e.g., Atherosclerosis, Parkinson
3. Allergy – By the presence of foreign substances the person becomes highly stressed, e.g., Rhinitis (nasal related).
4. Addiction – These diseases are caused by addictive drugs, alcohol, and tobacco.
5. Mental Disorders – These diseases are related with stress, anxiety, mental disabilities, madness, schizophrenia and psychosis.
6. Cancer – It is one of the main causes of death in which cells divide continuously, crushing of normal cells, dying of cells due to starvation and starting loss of essential organs.

Infectious diseases

Infectious Diseases – These diseases are caused by pathogens and parasites. These can be transferred from an infected person to a healthy person. Thus also called communicable disease. Transmission may be through direct contact or by factors such as blood and serum.

• Contagious Disease – These diseases are spread by direct contact with a healthy person. For example ring worm,  Conjunctivitis.
• Non-contagious Diseases – These diseases can spread by infected factor carrier (e.g. Dengue, Malaria), blood, serum (AIDS, Typhus fever)

Disease caused by Bacteria

Disease	Causative Bacterium	Main Symptoms	Mode of Transmission
Leprosy (Hansen’s disease)	Mycobacterium leprae	Skin rashes, ulcers, finger/toe deformities, nerve damage	Direct contact with patient, discharge from wounds
Tuberculosis (T.B.)	Mycobacterium tuberculosis	Persistent cough (sometimes with blood), fever, weight loss, weakness	Airborne (coughing, sneezing)
Diphtheria	Corynebacterium diphtheriae	Thick coating in throat, fever, breathing difficulty	Droplets, touching infected items
Tetanus	Clostridium tetani	Muscle stiffness, jaw lock, body cramps	Entry through wounds/cuts
Pneumonia	Diplococcus pneumoniae	Fever, chest pain, cough, breathing difficulty	Airborne droplets
Diarrhoea	Shigella group, E. coli, Salmonella	Watery stool, vomiting, dehydration, weakness	Contaminated food or water
Meningitis	Neisseria meningitidis	Headache, high fever, vomiting, neck stiffness	Contact or droplets from patient
Gonorrhoea	Neisseria gonorrhoeae	Yellow discharge, painful urination, genital inflammation	Sexual contact
Cholera	Vibrio cholerae	Diarrhea, vomiting, dehydration, muscle cramps	Contaminated water/food
Typhoid	Salmonella typhi	Fever, headache, stomach pain, rashes, weakness	Contaminated food/water or contact
Whooping Cough (Pertussis)	Bordetella pertussis	Dry cough with a whooping sound, mild fever, breathing difficulty	Air droplets
Melioidosis	Burkholderia pseudomallei	Fever, cough, headache, chest pain, muscle pain.	Bacteria live in soil and water, and can persist for years in contaminated environments.Person-to-person transmission is very rare

Disease caused by Protozoa

Disease	Causative Organism	Vector / Transmission	Main Symptoms
Amoebiasis (Amoebic Dysentery)	Entamoeba histolytica	Contaminated food & water; spread by houseflies	Loose motions with mucus/blood, stomach cramps, weakness
Giardiasis	Giardia lamblia	Contaminated food & water	Loose motions, stomach ache, headache, loss of appetite
Trypanosomiasis (Sleeping Sickness)	Trypanosoma gambiense	Bite of the Tsetse fly (Glossina palpalis)	Swelling in glands, headache, and constant sleepiness.Kenya has eliminated sleeping sickness
Malaria	Plasmodium sp. (P. vivax, P. falciparum, P. malariae, P. ovale)	Bite of a Female Anopheles mosquito	Fever with chills, headache, vomiting, weakness
Leishmaniasis (Kala-Azar)	Leishmania donovani	Bite of Sandfly	Swelling of spleen & liver, boils on skin, affects nose & throat
Trichomoniasis	Trichomonas vaginalis	Sexual contact	Foamy discharge, itching, burning, vaginitis
Toxoplasmosis	Toxoplasma gondii	Contact with infected animals or contaminated food	Affects the brain and nerves, hydrocephalus, chorioretinitis

Diseases caused by Virus

Disease	Causative Virus	Mode of Transmission	Main Symptoms
AIDS (Acquired Immuno Deficiency Syndrome)	Human Immunodeficiency Virus (HIV)	Unsafe sexual contact, infected blood transfusion, shared needles, mother to child	Weak immune system, weight loss, fever, fatigue, frequent infections
Polio	Poliovirus	Contaminated food and water	Fever, cough, vomiting, paralysis of limbs, and breathing difficulty
Hepatitis A	Hepatitis A Virus (HAV)	Contaminated food and water	Jaundice, loss of appetite, vomiting, yellow eyes, and urine
Hepatitis B	Hepatitis B Virus (HBV)	Infected blood, needles, sexual contact, mother to child	Fever, jaundice, dark urine, liver swelling, low appetite
Hepatitis D	Hepatitis D Virus	carcinogenic to humanscauses of liver cancer	Fever, jaundice, dark urine, liver swelling, low appetiteNo separate vaccine for Hepatitis D
Rabies	Rabies virus	Bite of infected animals (dog, cat, monkey, etc.)	Pain and inflammation at the bite site, fear of water, fits, difficulty swallowing
Mumps	Mumps virus (Paramyxovirus)	Airborne droplets (cough/sneeze)	Swelling of salivary glands, fever, headache, pain while swallowing
Influenza (Flu)	Influenza virus	Airborne droplets from a cough/sneeze	Fever, headache, muscle pain, sore throat, tiredness
Jaundice (Viral type)	Hepatitis viruses (mainly A & E)	Contaminated food and water	Fever, yellow skin and eyes, loss of appetite, weakness
Smallpox	Variola virus	Airborne droplets or direct contact	High fever, rashes, fluid-filled pustules on skin
Common Cold	Rhinovirus	Airborne droplets or contact with an infected surface	Runny nose, sore throat, mild fever, sneezing

Diseases caused by helminths

• Dracunculosis – Also called Nairu disease.
• Some other common examples 
• Trichariasis 
• Filarisis( Japanese Elephantatists) – Caused by Wucharia Boncrafti

Diseases caused by Fungus

Some specific disease

AIDS (Acquired Immuno Deficiency Syndrome)

• Cause: HIV virus
• How it spreads: From body fluids(blood, breastmilk, semen,vaginal fluid) of an infected person, Sexual contact, Through infected needles/syringes, Blood transfusion, From infected mother to her baby during pregnancy, delivery  or breastfeeding, From infected blades/sharp objects
• Symptoms: Swollen lymph glands, Low platelets → fever & bleeding, Night sweating, Weight loss, Memory loss, weak thinking, Higher risk of other infections due to low immunity
• Prevention: Do not share needles/blades, HIV test before blood transfusion, Use new blade while shaving, Safe sexual practices, and healthy lifestyle
• Treatment: ART (Anti-Retroviral Therapy), No complete cure, but treatment effectively controls virus

Naru / Bala (Guinea Worm Disease)

• Cause: Worms (30–125 cm long)
• Transmission: Through contaminated drinking water containing Cyclops microorganisms.
• Causes of disease: Drinking unclean/impure water, Drinking pond/bavdi water, Drinking unfiltered water
• Symptoms: Boils on legs and hands, Severe pain at boil site, Fever, Female worms grow in muscles, If worm dies inside, it poisons lymph nodes
• Prevention: Drink boiled/filtered water
• Treatment: Removal of worm, proper medical care

Swine Flu

• Cause: H1N1 influenza virus
• Spread by contact with infected person
• Symptoms: Sore throat, cough, Cold, Fever, Body aches
• Prevention: Frequent handwashing, Use handkerchief/tissue while coughing, Avoid crowded places , Use mask
• Treatment: Tamiflu tablets as prescribed by doctor

Food Poisoning

• Cause: Eating microbial contaminated( E. coli, salmonella) or spoiled food, Microbes produce toxins that make food poisonous
• Symptoms: Vomiting, nausea, stomach cramps, diarrhoea
• Prevention: Avoid stale or contaminated food, Maintain kitchen hygiene
• Treatment: Timely doctor advice, ORS to prevent dehydration

Cancer

• Cause: Uncontrolled cell division, Rapid and abnormal growth of cells
• Symptoms: Tumour formation, Painless lumps in early stages, Severe pain in later stages, Tumours may occur in tongue, throat, lungs, blood, uterus etc.
• Prevention: Early diagnosis, Avoid tobacco, alcohol, Healthy lifestyle, Safe radiation exposure
• Treatment: Surgery, chemotherapy, radiotherapy (cobalt therapy)

Dengue  

• A viral disease caused by Dengue virus, spread by Aedes aegypti (female) mosquito.  
• Transmission:  Bite of infected Aedes mosquito.  
• Causes:  Mosquito breeding in dirty or stagnant water, Low platelet count
• Symptoms (start after 3–14 days):  Fever with shivering, Headache, Pain in eyes, Joint/body pain, Loss of appetite  Vomiting, Diarrhoea, Red rashes on skin. 
• Prevention:  Do not allow standing water, Clean containers weekly, Use insecticides, Keep coolers dry when not in use  
• Treatment:  As advised by doctor (No self-medication)

Anemia

• Cause: Deficiency of haemoglobin and blood.
• Symptoms: Pale face, Weakness, Tiredness, Giddiness / Vertigo,White boils on tongue
• Prevention: Eat nutritious food: sprouted grains, green vegetables, anjeer, beetroot, brinjal, sesame, etc.
• Treatment: Iron tablets
• Important: Government provides free iron tablets to adolescents.

Mode of Transmission of Disease

Diseases caused by deficiencies

Protein deficiency

Vitamin deficiency

Vitamin name	Chemical name	Disease caused by deficiency	Deficiency Symptoms
A	Ratinol	Night blindness	Difficulty seeing in low light, such as driving at night, and trouble adjusting from bright to dark environments.
		Xerophthalmia(dry eye)	Include dryness, burning, gritty feelings, and difficulty seeing at night.
D	CalciferolOsteomalacia	Rickets disease	Include delayed growth, bone pain, muscle weakness, and skeletal deformities like bowed legs or a protruding breastbone.
E	Tocopherol	Infertility, paralysis
K	NaphthoquinonePhylloquinone	Bleeding,  No formation of blood clot	Excessive bleeding from minor cuts, easy bruising, nosebleeds, and heavy menstrual bleeding.
C	Ascorbic acid	Scurvy	Include fatigue, joint pain, and swollen, bleeding gums.
B 1	Thiamine	Beriberi	Include numbness, tingling, muscle weakness, difficulty walking, and mental confusion.
B 2	Riboflavin	Cheilosis	Include cracked and split corners of the mouth, redness, swelling, dryness, and crusting at the corners of the mouth
B 3	Nicotinic acidNiacin	Pellagra	“3 D’s”: dermatitis (skin rash, especially on sun-exposed areas), diarrhea (digestive issues), and dementia (mental confusion, memory loss).
B 5	Pantothenic acid	Burning feet syndrome	Involves a burning sensation in the hands and feet. Other effects can include fatigue, irritability, numbness, muscle cramps, skin problems.
B 6	Pyridoxine	Dermatitis, Anemia	Include itchiness, dry or cracked skin, redness, and rashes
B 9	Folic acid	Megaloblastic anemia	fatigue, weakness, pale skin, and shortness of breath
B 12	Cyanocobalamin	Pernicious anaemia	Include fatigue, pale skin, and shortness of breath from the anemia itself, as well as neurological issues like numbness, tingling, confusion, and memory problems
B 7 (H)	Biotin	Spectacle eye, fall of hair	Includes hair loss, skin rashes (often around the eyes, nose, and mouth), and brittle nails.

Note:- Vitamin – A,D,E,K are fat soluble. Vitamin– B complex ,C are water soluble

Disease caused by hormone abnormalities

Gland	Hormone secreted	Hyper/hypo secretion	Disease
Adrenal gland	EstrogenTestosterone	Hyper secretion	Conn’s diseaseCushing diseaseHirsutism or adrenal virilismGynaecomastiaOedema
Pancreas	Insulin	Hypo secretion	Diabetes MellitusPolyureaPolydipsiaKetosis
		Hyper secretion	Hypoglycemia
Parathyroid gland	Parathormone	Hypo secretion	Hypocalcemic Tetany
		Hyper secretion	OsteoporosisOsteitis fibrosa cystica
Thyroid gland	Thyroxine	Hypo secretion	CretinismMyxoedemaGoiterHashimoto’s disease
		Hyper secretion	Exophthalmic goiterPlummer’s diseaseGraves disease
Pituitary gland	ADH (Vasopressin)	Hypo secretion	Diabetes insipidus
	Growth hormone	Hypo secretion	DwarfismAteliosis
		Hyper secretion	GigantismAcromegalySimmonds disease
Gonads	Estrogen	Hyper secretion	Irregular menstrual cycle

Syndromes

• Chromosome are thread like structured capable of automatic generation. These are situated in nucleus. These can be studied easily after  staining. They carry hereditary characters from one generation to other generation so these are known as carriers of heredity. 
• 1848, Hofmeister observed chromosomes in pollen grain mother cell of Tradescantia. In 1888, Waldeyer called these structures as chromosomes.
• Autosomes and Sex chromosomes
• 23 pairs of chromosomes means 46 chromosomes are found in human. Out of these 46 chromosomes 44 chromosomes are similar in male and female which are known as somatic or asexual chromosomes or autosomes.
• In males remaining two chromosomes one chromosome is smaller and the other is bigger. These are respectively known as X and Y chromosomes. 
• In female human both the chromosomes are similar and are known as XX chromosomes. 
• Thus in human species, total 44 + XY = 46 chromosomes are found in males and 44+XX = 46 chromosomes in females.
• Broadly, genetic disorders may be grouped into two categories – Mendelian disorders and Chromosomal disorders. 

Chromosomal disorders

• Mendelian disorders are mainly determined by alteration or mutation in a single gene. These disorders are transmitted to the offspring on the same lines as we have studied in the principle of inheritance. The pattern of inheritance of such Mendelian disorders can be traced in a family by the pedigree analysis. Most common and prevalent Mendelian disorders are Haemophilia, Cystic fibrosis, Sickle cell anaemia, Colour blindness, Phenylketonuria, Thalassemia, etc. 
• It is evident that this X-linked recessive trait shows transmission from carrier female to male progeny.

Mendelian disorders

Other syndromes

Zoonotic disease

• Zoonotic diseases are infectious illnesses that spread between animals and humans. 
• Zoonotic diseases spread through contact with infected body fluids, animal bites, contaminated water and eating infected meat. 
• Bats, livestock, rodents, birds, and other vertebrates can carry them.
• The word Zoonoses was coined by Rudolf Virchow (1959).
• World Zoonoses Day is observed on 6 July.
• Theme of 2025  – One health: United against Zoonotic threats

Types	Features	Common examples
Bacterial Zoonoses:	These are diseases caused by bacteria — microscopic single-celled organisms that can release toxins and make you sick.	Anthrax, Brucellosis, Cat scratch disease, Lyme disease, Mycoplasma, Pneumoniae, Plague, Q fever, Salmonella, Tularemia, and Tuberculosis.
Parasitic Zoonoses:	These diseases are caused by parasites such as Worms, Protozoa (single-celled organisms), or external parasites like lice and mites.	Toxoplasmosis, Giardiasis, Liver fluke, Malaria, Taeniasis (a tapeworm infection from pork or beef), and Trichinosis.
Viral Zoonoses:	Viruses are submicroscopic infectious agents that enter our cells to make more copies of themselves.	Japanese encephalitis,  Chikungunya, Rabies, Chandipura, Kyasanur forest disease,  Buffalo Pox, Nipah virus, Gunjan virus, Bhanja virus, Lassa fever, COVID-19, Monkeypox, HIV AIDS, Ebola, Hantaanavian influenza (bird flu), Marburg virus disease, Mpox, and Rabies.

Non-zoonotic disease

• Lumpy Skin Disease – viral, cattle only
• Rinderpest – viral, cattle only (eradicated now)
• Foot and Mouth Disease (FMD) – viral, cattle, sheep, goats, pigs (not in humans)
• Newcastle Disease – viral, poultry only
• Marek’s Disease – viral, poultry only
• Classical Swine Fever (Hog Cholera) – viral, pigs only
• African Swine Fever – viral, pigs only
• Sheep Pox & Goat Pox – viral, sheep/goat only
• Avian Infectious Bronchitis – poultry only
• Bovine Ephemeral Fever – cattle only

State-wide FMD Disease Control Program

• Launch : By Animal Husbandry Minister Joraram Kumawat on September 24, 2025, at Pinjrapole Gaushala (Cowshed) in Pali.
• The 6th round disease control vaccination drive for F.M.D. (Foot-and-Mouth Disease) will be carried out in the state under the National Animal Disease Control Program during the year 2025-26, and the campaign program will run until November 23, 2025.

Autoimmune disease

Immune System – It protects our body from harmful things like viruses, bacteria, and toxins. It works automatically to find and fight these invaders. It sends white blood cells to destroy them before they can make you sick.

Autoimmune diseases are health conditions that happen when your immune system attacks your body instead of defending it. Sometimes, the immune system becomes too active. When there are no germs to fight, it mistakenly attacks your own healthy cells. This attack damages your body’s normal tissues.

Examples

1. Celiac disease                                     7. Inflammatory bowel disease
2. Type 1 Diabetes Mellitus                  8. Rheumatoid arthritis (RA)
3. Addison’s disease                               9. Multiple sclerosis
4. Pernicious anemia                              10. Systemic lupus erythematosus
5. Myasthenia gravis                               11. Psoriasis / Psoriatic arthritis
6. Hashimoto’s thyroiditis                      12. Lichen planus
7. Vitiligo

Rare disease

• WHO defines a rare disease as an often debilitating lifelong disease or disorder with a prevalence of 1 or less per 1000 people. 
• Examples – SMA type 2 , Cystinosis , Pompe , Gaucher disease , Hunter syndrome

Initiative of Rajasthan Government

• Government of Rajasthan announced rare diseases fund of 50 crore
• Rare diseases Day is observed on the last day of February month 
• For diagnosis and treatment of rare diseases center of excellence for medical Genetics will be established at JK loan Hospital, Jaipur
• “Raj Sambal” portal – Rare diseases crowdfunding portal

Disorders

Disorders	Cause / Description	Examples
Biochemical Disorders	Caused by excess or deficiency of biochemicals like hormones, enzymes, or body wastes.	Hormone imbalance, high urea, uric acid, creatinine problems
Exogenous Chemical Disorders	Caused by exposure to pollutants, chemicals, or allergens from the environment.	Asthma, allergy, chemical poisoning
Lifestyle Disorders	Caused by unhealthy food habits, lack of exercise, stress, or addictions.NCDs(Non-Communicable disease) also known as chronic diseases, tend to be of long duration and are the result of a combination of genetic, physiological, environmental and behavioural factors.	Obesity, diabetes, heart disease, hypertension
Mechanical Disorders	Caused by physical injuries or damage to body parts.	Bone fracture, sprain, joint injury
Degenerative Disorders	Related to ageing; tissues or organs gradually lose function.	Arthritis, atherosclerosis, heart disease, hypertension
Genetic Disorders	Caused by defects in genes passed from parents to offspring.	Color blindness, Down syndrome, hemophilia
Mental Disorders	Caused by emotional, social, or psychological problems.	Depression, anxiety, schizophrenia

Eye-related disease

Body parts affected

Disease	The organ affected mainly
Jaundice, Hepatitis	Liver
Japanese encephalitis, Meningitis, Sleeping sickness, Primary Amoebic Meningoencephalitis (PAM)	Brain
Night blindness, Trachoma, Myopia, Hypermetropia, Glaucoma,  color blindness, Cataract, presbyopia	Eye
Malaria	Liver, Kidney
Diarrhoea	Large Intestine
Goiter	Thyroid gland
Tuberculosis, pneumonia	Lungs
Scurvy, Pyorrhea	Teeth gums
Typhoid, Cholera, Dysentery	Intestine
Tetanus, Epilepsy, Rabies	Nervous system
AIDS	Defensive system (WBC) Lymphocytes
Polio	Spinal cord, Throat, backbone, Nervous system
Diphtheria, Whooping cough	Respiratory tube
Plague	Lungs, Lymph node, the area between the two legs
Leprosy	Nervous System Skin
Gonorrhea, Syphilis	Urinary Path

Tests for the diagnosis of diseases

Disease	Test for diagnosis
Kala-azar (leishmaniasis)	Colloidal antimony test
Syphilis	VDRL test
Deficiency of Vitamin C	Capillary fragility test
Diphtheria	SCHICK
Syphilis	Treponemal test
Leukemia	Complete blood count (CBC)
Typhoid	Widal test
AIDS	ELISA, Western blot, CD4 cluster of differentiation
The inflammation-causing factor in the body	ESR (erythrocyte sedimentation rate)
Swine flu	H1N1
(Leprosy)Hansen’s disease	Lepromin test
Color blindness	Ishihara test
Tuberculosis	Mantoux test
Osteoporosis	B.M.D. test
To measure the interaction between platelets and von Willebrand factor	R.I.P.A (Ristocetin-Induced Platelet Aggregation)
Autoimmune hemolytic anemia	Coombs test

Disease spreads from Mosquitoes and flies

Antimicrobial resistance

• AMR – Occurs when bacteria, viruses, fungi, and parasites evolve to resist medicines over time and making antibiotics ineffective against them, making infections harder to treat and increasing the risk of spread of disease, illness and death.
• The World Health Organization (WHO) has identified AMR as one of the top 10 global public health threats.
• Nearly 7,00,000 people die of antimicrobial resistance every year.
• Reason– misuse of antibiotics, inadequate dosage and duration, self-medication

Measures Taken to Rising Anti-Microbial Resistance in The Country

• The national programme on AMR containment was launched
• National Action Plan on Antimicrobial Resistance (NAP-AMR), focusing on the One Health approach, was launched on 19th April 2017.
• ICMR established the AMR Surveillance and Research Network (AMRSN) in 2013,
• The Kerala Drug Control Department launched tests in the first week of January 2024 called Operation Amrith (AMRITH – Antimicrobial Resistance Intervention For Total Health) to prevent the overuse of antibiotics in the state.
• The nPROUD (New Programme for Removal of Unused Drugs) initiative was launched by Kerala to provide a systematic, government-led method for collecting and scientifically disposing of unused and expired medicines from households and pharmacies.

Immune System

At some point in life, everyone experiences infections caused by disease causing agents such as bacteria, viruses, fungi and parasites. We all have a system in the body to prevent these disease causing factors. This system is called the Immune System. This system protects us from the infection caused by disease causing factors. 

Immunity is broadly defined as “the capacity of the body to recognize materials as foreign to itself and to neutralize, eliminate or metabolize them with or without injury to its own tissues”. 

Edward Jenner (1749-1823) is considered to be the father of modern immunobiology.

Type of Immunity

Immunity is of two types : (I) Natural or Innate immunity (II) Acquired Immunity

Natural Immunity

A healthy individual is generally immune to potentially harmful microorganisms through a number of very effective mechanisms. These mechanisms are termed innate or natural immunity. Innate defence consists of

Physical barrier

• This prevents the disease causing micro-organism to enter the body. So this is first defense line. In this, the following organ participate :-

Skin

• The outer tough layer of skin is formed of keratin and is almost impermeable to germs. Sebaceous glands in the skin generate an acidic environment by producing lactic acid which kills many pathogens.
• Fat glands are attached with the hair follicle and they make an oily secretion called sebum. Sebum has lactic acid and fatty acid. These acids maintain the pH between 3 to 5 of the skin. Many of the micro organisms do not grow at this low pH. Intact skin prevent the entry of pathogens and its low pH prevent the growth of most bacteria. 
• Through a small cut in the skin or bites of various insect pathogen enters in the body and they causes infection.

Mucous Membrane

• Epithelial lining of various organs : The respiratory tract, the alimentary tract (the gut) and the urino-genital tract have an exterior epithelial cell layer covered by a protective mucous lining. 
• In the respiratory tract, cilia covering to the external surface of the epithelial cells continually beat upwards towards the nasopharynx and this helps to expel particles and pathogens. 
• Epithelial cells are constantly renewed and their removal expels pathogens lodged on their surface.

Physiological barriers (Body secretions)

• Body secretions such as sweat and secretion from eyes also ward off pathogens. Other body fluids contain molecules which are bactericidal (capable of killing bacteria) . Such as spermine and zinc in seminal fluid, HCL acid in gastric juice, lactoperoxidase in milk, lysozyme enzyme in tears, saliva and nasal secretions.

If the bacteria enter in the body then the other two immunity processes start their functions. 

• First the soluble chemical factors start their bactericidal effect which is called complement system and second by phagocytosis they are killed.

Complement system

• The group of proteins known as ‘complement’ provides another innate immunity mechanism for killing microbes without prior phagocytosis.
• The complement system is a group of more than 30 proteins. Components of some complement system are represented by the letter ‘C’ and with this it is displayed by the number. The number written in it represent the sequence of its discovery. Out of these the most important and the commonly found component is C₃.
• Complement component may also act as opson in (e.g. C36). Opson is that type of antibody whose binding to antigens on virus or bacterium facilitates their subsequent ingestion by the phagocytic cells. Such antibodies can also cause direct destruction of microbes by making their membrane leaky.

Cellular Phagocytic Barrier

• When the micro-organisms or inert particles such as colloidal carbon enter the tissue fluid or blood stream, these are very rapidly engulfed and destroyed by phagocytic cells. Such cells may either be circulating in body fluids or may be fixed in some tissues. This phenomenon is called phagocytosis (literally meaning ‘eating’ by the cell). The engulfment and destruction/digestion of microorganisms is assigned to two major types of cells named as microphages (certain WBC) and macrophages (in Liver and Spleen).
• Important features of phagocytic cells
  1. They rapidly engulf the foreign molecular foreign agent on coming in contact or which they come in contact with.
  2. They contain digestive enzymes to breakdown engulfed material.
  3. They are an important link between innate and acquired immunity

Inflammatory Barrier/Cytokine Barrier

• The various tissues of the body in which the wound developed due to injury or damaged cells due to infection of pathogens, at that spot radness, pain and heat is generated.  In this, most cells of connective tissue and basophil cells of white blood corpuscles, secrete histamine and prostaglandin as chemical warning which generate inflammation. Due to spreading these, the blood capillaries become more permeable.
•  These different complex and sequence wise processes are collectively called inflammatory processes. 
• Plasma and phagocytes come out of the capillaries and do the work. The serum proteins present in plasma also have the bactericidal properties. Accumulation of these at a location, generate inflammation. Phagocytes destroy the micro-organism that enter into the body.

Acquired Immunity

• It is the immunity mediated by lymphocytes and characterized by antigen specificity and memory.
• This is developed by the organism on the basis of former memory power of micro-organism or the metabolic substances produced by them. It develops in the form of resistivity of the disease during the life span of the organism. 

Acquired Immunity–

This immunity is antigen specific. Its main property is memory. When disease causing factors enter into the body for the first time, the immune system reacts by producing antibodies called primary response. 

During this process memory cells are produced. Thus, when the same disease causing factor enters into the body again, then the immune system produces excess antibodies with the help of former memory cells and responds rapidly. This is called secondary immune response.

Acquired immunity is of two types :-

Active Immunity 

• When disease causing organism or antigen enter into the body and antibodies are formed then this type of immunity is called active immunity. This immunity is slow and takes time to become effective but its effect remains for long periods. The natural active immunity is developed when infectious organism enter into body by natural infection while, when disease causing organism or antigen is intentionally introduced in the body by vaccination then artificial active immunity is developed.
• Some infections, such as diphtheria, whooping cough, smallpox and mumps usually induce a lifetime immunity i.e. a patient once recovered does not get the disease subsequently.
• Other diseases such as common cold, influenza, bacillary dysentery and pneumococcal pneumonia confer immunity for a shorter period, sometimes only for a few weeks.

Passive Immunity 

• When the preformed antibodies are introduced into body for the protection then passive immunity is obtained. This immunity develops rapidly but remain effective for a short duration. During pregnancy, the embryo gets IgG through placenta and during lactation the mother provides the new born child IgA through colostrum which are example of passive immunity. 
• The antivenom/antitoxin given in the treatment of snake bite or dangerous disease such as tetanus, rabies, diphtheria, produce the artificial passive immunity.
• It may be developed in the following ways :

1. Transfer of antibodies (e.g. IgG) from mother into foetus across the placenta.
2. Breast fed children also receive antibodies from the mother’s milk.
3. Pooled human immunoglobulin is also used as source of antibody in a number of cases including measles infection and infectious hepatitis.
4. Human immunoglobulin is also given to patients with a congenital inability to make antibody globulin.

Autoimmunity 

• There is a capacity of differentiating between self and the cells of heterogeneous organism in the acquired immunity. It means this immunity develop antibodies only against heterogeneous organism. 
• But sometime, due to heredity, environment or other reasons this immunity makes antibodies against self cells and attacks on its own cells. 
• This type of immunity is called auto immunity and the disease resulting from auto immunity is called auto immune disease. eg.  Rheumatoid arthritis

Herd Immunity

• It means when most people in a community are immune (through vaccination or past infection), the spread of a disease becomes very low. This also protects those who are not immune.
• Examples:
• Polio in India – Mass vaccination created herd immunity, helping to stop the spread.
• Measles – If 90–95% children are vaccinated, the disease cannot spread easily.
• COVID-19 – Communities with high vaccination and past infection levels had reduced spread.

Primary vs Secondary Immune Response

• Primary Response (First time infection/vaccine)
  • The body takes time to recognize the germ.
  • Antibodies are produced slowly and in small amounts.
  • Protection is weak and short-lived.
• Secondary Response (Next time same germ enters)
  • Memory cells (made during first infection) recognize the germ immediately.
  • Antibodies are produced very quickly and in large amounts.
  • Response is stronger, faster, and long-lasting.

Cells of Immune System

Lymphocytes (Lymphoid cells) – are key white blood cells in the immune system that fight infection by recognizing and attacking pathogens. 

• All these are initially derived from the hemopoietic (blood cell producing) stem cells of bone narrow. Stem cells mean undifferentiated cells which can undergo unlimited division and can give rise to one or several different cell types. 
• Stem cells in bone marrow produce lymphocytes.  Bone marrow stem cells also differentiate to produce erythrocytes (red blood cells), thrombocytes (blood platelets), granulocytes and monocytes (white blood cells).
• Lymphocytes are divided into two sub-classes:

The macrophage – These are derived from monocytes.

ANTIGEN AND ANTIBODY

• Antigen – An antigen is any foreign molecule that can trigger a specific immune response. Most antigens are either proteins or very large polysaccharides.
• Antibody – Antibody is a protein molecule produced in animals in response to an antigen. Each antibody molecule is composed of four interlinked polypeptide chains.

Type of immunoglobulins (Antibodies)

There are five major classes of antibodies (or immunoglobulins) distinguished by the amino acid sequences in the heavy chains. These classes are designated as Ig, IgD, IgA, IgE, IgG and IgM (Ig = Immunoglobulin)

• IgE – Role in allergic reactions and protection against parasites.
• IgG – Only antibody that can cross the placenta. Provides passive immunity to the fetus.
• IgM – Largest antibody. First antibody produced in the human body in response to infection.
• IgA – Found in colostrum (mother’s first milk, 2–3 days after childbirth). Protects newborn against infections.
• IgD – Present in small amounts on the surface of immature B lymphocytes. Helps in activation of B-cells

They also differ in their molecular weights and functions.IgG is found in highest concentration (almost 75% of the total immunogloblulins in humans).

Vaccination

People had observed in the past that individuals who recovered from certain diseases are protected for lifetime from recurrences. This gave rise to the concept of immunization. Edward Jenner introduced vaccination in 1796 using cowpox to protect against smallpox.

The objective of vaccination is to introduce the attenuated germs into the body. The body then generates specific population of memory cells. These memory cells can rapidly increase in number on the renewed contact with the same antigen and more antibodies can be produced to provide protection against infection.

Type of Vaccine

Following types of vaccine are used 

Live, Diluted and Attenuated Vaccines 

• In order to make a living attenuated vaccine, pathogenic virus is cultured by tissue culture or cultured in animal embryo such as chick embryo for many generations. Due to which replication properties in human is eliminated. But this virus can be detected by the human immune system. Eg. Rubella, Measles, Rotavirus and Oral polio etc.

Killed or Inactivated Organism Vaccine

• This type of vaccines are created by deactivating a pathogen. For this, usually the pathogenic factor is heated or treated with chemicals such as formaldehyde or phosphorin to destroy their division capacity but the antigen properties of pathogen are preserved so that the immune system can identify it. Examples : Typhoid, Cholera, Pertussis (whooping cough), Rabies and Poliomyelitis.

Toxoid Vaccine

• Some bacterial diseases are not caused by bacteria directly, but they are caused by toxins produced by them. One example of this is – Tetanus. The symptoms of this are not because of Clostridiumtetan or bacteria but it is because of neurotoxin-tetanospasmin secreted by them. it causes tetanus disease. So, to prevent it toxoid vaccines is used. The toxoid vaccine is made by physical and chemical refining process of toxins to make them harmless but its immunogenicity is maintained. For example – diphtheria, tetanus etc.

Conjugate and Unit Vaccines 

• Conjugate vaccines are like recombinant vaccines. They are made from two separate components. They link bacterial sugar coatings (polysaccharides) to a protein carrier, creating stronger immunity, especially in infants; key examples include Haemophilus influenzae type b (Hib), Pneumococcal Conjugate Vaccines (PCV), and Meningococcal Conjugate Vaccines, all preventing severe infections like meningitis, plus the newer Typhoid Conjugate Vaccines (TCV).
• In unit vaccines, only one portion of target pathogen is used for the stimulation of immune response by immune system. In this, a specific protein is isolated from specific pathogen and it is introduced into body as an antigen. Eg. Acellular pertussis vaccine and influenza vaccines 

Engineered Vaccine 

• The production of vaccines at a large scale is done with the help of recombination technique in which the antigen of the pathogen is produced in yeast or bacteria Eg. Hepatitis vaccine

Vaccine

Vaccine	Disease
Men5CV	Meningitis
Hillcol-(BBV-131), Euvichol-Plus	Cholera
RTS,S-01 , R21/Matrix-M, Ad FalciVax	Malaria
MVA-BN , Jynneos	Monkeypox
TAK-003, DengiAll	Dengue
Cadflu-S	Influenza
DPT vaccine	Diphtheria – Pertussis ( Whooping cough) – Tetanus
MMR vaccine	Attenuated strain of measles, mumps and Rubella
Pentavalent vaccine	Diphtheria, Pertussis, Tetanus, Hepatitis B, and Hib
BCG(Bacillo Calmette Guerin) vaccine	Tuberculosis (TB)
Pneumococcal vaccine	Pneumococcal diseases (pneumonia, meningitis, ear/sinus infections)
JE vaccine	Japanese encephalitis
EnteroMix vaccine	Cancer (ready for clinical use made by Russia)

Mission Indradhanush 

• It is a health mission launched  on 25 December 2014.
• The aim is to reach at least 90% vaccination.

Intensified Mission Indradhanush 5.0

• Aim To enhance immunization coverage for all vaccines provided under the Universal Immunization Programme (UIP) as per the National Immunization Schedule (NIS).
• It is being conducted across all the districts in the country and includes children up to 5 years of age (Previous campaigns included children up to 2 years).
• Provides 12 vaccine free of cost against  preventable diseases
• Diphtheria, Pertussis, Tetanus, Polio, Measles, Rubella, severe form of Childhood Tuberculosis, Hepatitis B and Meningitis & Pneumonia caused by Hemophilus Influenza type B ,  Rotavirus diarrhoea, Pneumococcal Pneumonia and Japanese Encephalitis

Drugs and their classification

Drugs are chemicals of low molecular masses (~100 – 500u). These interact with macromolecular targets and produce a biological response. When the biological response is therapeutic and useful, these chemicals are called medicines and are used in diagnosis, prevention and treatment of diseases. If taken in doses higher than those recommended, most of the drugs used as medicines are potential poisons. Use of chemicals for therapeutic effect is called chemotherapy.

Classification of Drugs

Basis of Classification	Details
On the basis of pharmacological effect	This classification is based on pharmacological effect of the drugs. It is useful for doctors because it provides them the whole range of drugs available for the treatment of a particular type of problem. For example, analgesics have pain killing effect, antiseptics kill or arrest the growth of microorganisms.
On the basis of drug action	It is based on the action of a drug on a particular biochemical process. For example, all antihistamines inhibit the action of the compound, histamine which causes inflammation in the body. There are various ways in which action of histamines can be blocked.
On the basis of chemical structure	It is based on the chemical structure of the drug. Drugs classified in this way share common structural features and often have similar pharmacological activity. For example, sulphonamides have common structural feature, given below. HN – NHR Structural features of sulphonamides
On the basis of molecular targets	Drugs usually interact with biomolecules such as carbohydrates, lipids, proteins and nucleic acids. These are called target molecules or drug targets. Drugs possessing some common structural features may have the same mechanism of action on targets. The classification based on molecular targets is the most useful classification for medicinal chemists.

Neurologically Active Drugs

Antimicrobials

Diseases in human beings and animals may be caused by a variety of microorganisms such as bacteria, virus, fungi and other pathogens.An antimicrobial tends to destroy/prevent development or inhibit the pathogenic action of microbes such as bacteria (antibacterial drugs), fungi (antifungal agents), virus (antiviral agents), or other parasites (antiparasitic drugs) selectively. Antibiotics, antiseptics and disinfectants are antimicrobial drugs.

Provisions for medical and health in budget 2025-26

• MAA Fund’ of Rs 3,500 crores constituted for free testing and medicines to the general public. Interstate portability implemented in MAA scheme. 
• Free medicine at home for senior citizens above 70 years of age. 
• Diabetic clinics established in all district hospitals. 
• Digital X-ray, TRU-NAAT and CB-NAAT machine will be available at CHCs for a TB free state.
• MAA Eye Voucher Scheme applicable for free eye check up and operation.
• 148 Urban Ayushman Arogya Mandirs (UAAM) will be established.
• Upgradation of Vitreo Retina Surgery Unit in Bikaner Hospital.
• Augmentation of Spinal Injury Centre capacity to 120-bed capacity at Jaipur, Bikaner, Jodhpur, Udaipur, Kota.
• Rs 195 crore for cancer unit and cottage ward in Kota Medical College.
• Establishment of Ultra Advanced Burn Care Centre at each divisional headquarters
• Rs 500 crore for upgradation of Rajasthan Institute of MedicalSciences (RIMS), Jaipur; 
• Rs 50 crore provision for ‘Fit Rajasthan‘ campaign; Emphasis on reducing the amount of oil in the diet by 10%.
• Under New AYUSH Policy Rs 11 lakh incentive was provided by declaring villages as Ayushman Arogya Gram.
• Food laboratories will be established in 7 districts (Hanumangarh, Sawai Madhopur, Jaisalmer, Pali, Sirohi, Chittorgarh and Dungarpur).

Feature	Description / Explanation
Popular Sovereignty	The Constitution represents the will of the people; its legitimacy is derived from them. Supremacy lies with the people, not the legislature.
Parliamentary System of Government	The executive is not separate from the legislature but responsible to it. Follows the British parliamentary model. The President is a nominal head; real powers lie with the Prime Minister/Chief Minister. Dissolution of the lower house is possible.
Supremacy of the Constitution	Parliament, state legislatures, and other institutions must function within constitutional limits. The judiciary acts as the constitutional interpreter and guardian. Under Article 13, it can strike down unconstitutional laws.
Written and Most Comprehensive Constitution	Balances rigidity and flexibility; influenced by multiple sources.
Unitary and Federal Features	A federal system with unitary characteristics.
Emergency Provisions	Articles 352–360.
Democratic Features	Universal adult suffrage, citizenship, and fundamental duties.
Secularism and Socialism	Social welfare, reservation policies.
Fundamental Rights	Guarantees citizens’ fundamental rights.
Directive Principles of State Policy	Guide the state in policy-making.
Parliamentary Sovereignty & Judicial Supremacy	Ensures balanced governance.
Three-tier Government	Central, state, and local governance.
Judiciary	Integrated, hierarchical, independent, and balancing; power of judicial review.
Living Constitution	Flexible and adaptable according to time and circumstances.
Independent Bodies	Constitutional and non-constitutional bodies.
Cooperative Committees	Established for various social, economic, and administrative purposes.