2 Sept 2025·3 min read·

Diseases

A disease is a condition that disrupts the normal functioning of the body or its organs.
It may be caused by infections, lifestyle, genetics, or environmental factors.
Understanding diseases is crucial for exams like BPSC/CDPO/DPRO, especially in Bihar where diseases like Kala-azar, Malaria, and Diarrhea are endemic.

Classification of Diseases

1. Communicable Diseases

Spread from person to person via pathogens (bacteria, virus, etc.)
Examples: Malaria, Tuberculosis, Covid-19, Cholera, Measles
Caused by: Virus, Bacteria, Protozoa, Fungi, Worms

2. Non-Communicable Diseases (NCDs)

Do not spread; often due to lifestyle/genetics
Examples: Diabetes, Hypertension, Cancer, Heart diseases

📝 PYQ (BPSC): Which of the following is a communicable disease? → Tuberculosis
📝 Expected MCQ: Which is a non-communicable disease? → Diabetes

Types of Pathogens & Examples

Bacteria → Cholera, Tuberculosis, Typhoid
Virus → COVID-19, AIDS, Hepatitis, Measles
Protozoa → Malaria, Kala-azar
Fungi → Ringworm, Athlete's foot
Helminths → Filariasis, Worm infestations

📝 Expected MCQ: Which disease is caused by protozoa? → Kala-azar
📝 PYQ (CDPO): Which of these is viral? → Hepatitis

Symptoms vs Causes

Symptoms are effects (fever, cough, swelling)
Causes are agents (virus, bacteria, etc.)
Example: TB symptoms = cough, weight loss; cause = Mycobacterium tuberculosis

Major Diseases in Bihar

1. Kala-azar

Vector-borne (sand fly), caused by protozoa
Common in districts like Muzaffarpur, Vaishali, Samastipur
Govt runs National Kala-azar Elimination Programme

2. Malaria

Transmitted by female Anopheles mosquito
Common in flood-prone regions (e.g., Bhagalpur, Munger)

3. Diarrhea

Due to poor sanitation and contaminated water
Bihar has high burden in monsoon season

4. Tuberculosis (TB)

Airborne disease, chronic in slum areas
Bihar has high prevalence due to crowding & malnutrition

📝 Expected MCQ: Kala-azar is spread by? → Sand fly
📝 PYQ: Which Bihar districts are endemic for Kala-azar? → Muzaffarpur, Vaishali

Deficiency Diseases

Vitamin A → Night blindness
Vitamin C → Scurvy
Iron → Anemia (high in Bihar women)
Iodine → Goitre
Protein → Kwashiorkor, Marasmus

📝 PYQ: Night blindness is caused due to deficiency of? → Vitamin A
📝 Expected MCQ: Which deficiency causes anemia? → Iron

Modes of Disease Transmission

Airborne → TB, COVID-19
Waterborne → Cholera, Diarrhea
Vector-borne → Malaria, Kala-azar
Direct Contact → Skin diseases, STDs
Contaminated food → Typhoid, Hepatitis A

National Health Programs Relevant to Bihar

Ayushman Bharat Yojana → Health insurance for poor
National Tuberculosis Elimination Program (NTEP)
Kala-azar Elimination Program
Universal Immunization Program (UIP) – for children
Janani Suraksha Yojana (JSY) – promotes institutional delivery
Poshan Abhiyan – tackles child malnutrition

📝 Expected MCQ: Kala-azar elimination is targeted under which program? → NVBDCP
📝 Expected MCQ: Free health insurance for poor in India? → Ayushman Bharat

Prevention & Control

Vaccination (e.g., Polio, Measles)
Use of mosquito nets, clean drinking water
Nutrition programs to prevent deficiencies
Awareness through ASHA workers in rural Bihar
Sanitation and hygiene drives (Swachh Bharat)

PYQs + Expected MCQs

📝 PYQ (BPSC): Malaria is caused by...? → Plasmodium (protozoa)
📝 PYQ (CDPO): Which disease is due to deficiency of iron? → Anemia
📝 Expected MCQ: What is the cause of cholera? → Bacteria (Vibrio cholerae)
📝 Expected MCQ: Which vector spreads malaria? → Female Anopheles mosquito
📝 Expected MCQ: What causes TB? → Mycobacterium tuberculosis

Quick Revision Points

Diseases → Communicable (Malaria, TB) vs Non-communicable (Diabetes, Cancer)
Kala-azar → Sand fly, Bihar endemic
Deficiency diseases → Iron → Anemia, Vitamin A → Night blindness
Govt programs → Ayushman Bharat, Kala-azar Elimination, Poshan Abhiyaan
Prevention → Vaccines, clean water, nutrition, hygiene

Sources Used

NCERT Class 9–10 Science – Why Do We Fall Ill?
Lucent GK – Biology Section
Drishti Quick Book – Science
Ghatna Chakra & EduTeria PYQs – BPSC, CDPO, DPRO
National Health Mission Bihar Reports
NVBDCP – Vector-borne Disease Program
Ministry of Health & Family Welfare