Modes of Disease Transmission

Simple Personal Hygiene

Health is defined as the physical, mental, social, and emotional fitness of a person. Hygiene is the science and practice of maintaining this good health. Personal hygiene involves four major aspects:

1. Cleanliness

• Hands and Skin: Must be washed regularly, especially after using toilets, to prevent picking up germs from public objects. A daily bath keeps skin clean, removes body odour, and clears sweat pores. Undergarments and handkerchiefs must be washed daily.
• Hair: Requires frequent washing and regular combing to stay healthy and free of parasites like head lice.
• Teeth: Should be cleaned at least twice a day (morning and night) to prevent cavities and gum infections. The mouth must be washed after every meal.
• Nose: Always breathe through the nose, never the mouth. Use a handkerchief when sneezing or blowing the nose.
• Eyes: Wash with clear water two or three times daily. To prevent infections like Trachoma and conjunctivitis, never share towels or applying sticks (like those used for kajal).
• Ears: Clean wax with a soft, moist swab. Never insert sharp objects into the ear as it may injure the eardrum.

2. Physical Exercise

• Essential for all age groups to improve blood circulation.
• Long gentle walks are excellent for the elderly, while exercise should be regular and systematic for everyone.

3. Rest and Sleep

• Adequate sleep is vital for organs, including the brain, to rest.
• Adults require 6-7 hours of continuous, undisturbed sleep, while infants sleep most of the day.

4. Healthy Habits

• Maintain regular timings for going to bed and eating.
• Bowels should ideally be cleared every day in the morning.
• Avoid tobacco (cancer-causing), alcohol, and unnecessary stimulants and sedatives.
• Ensure living rooms are well ventilated, as fresh air brings oxygen and sunlight kills germs.

Social Hygiene and Sanitation

• Public places (schools, offices, cinemas) and eating establishments must be kept clean and fly-free.
• Eatables must be covered, and utensils thoroughly washed with soap and hot water.
• Public drains and garbage should be covered and frequently sprinkled with disinfectants like bleaching powder.
• Civic bodies must supply clean drinking water and manage efficient sewage disposal.

Control of Disease-Carriers (Vectors)

Vectors are intermediate carriers of pathogens. Controlling insects and animals that spread diseases is a major priority for public health.

Houseflies ("Public Enemy No. 1")

• Transmission Methods: They spread dysentery, cholera, and typhoid. They pick up filth on their hairy bodies/legs, pour out saliva or vomit on food, deposit excreta on human food, and can directly transfer germs (like trachoma) by sitting on eyes.
• Control: Eliminate breeding places by covering and decomposing refuse. Spray houses with insecticides and protect food and sleeping babies with covers and nets.

Mosquitoes and Diseases

• Anopheles: Spreads malaria (caused by a protozoan called Plasmodium).
• Culex: Spreads elephantiasis/filariasis (caused by a nematode worm).
• Aedes: Spreads yellow fever and dengue (caused by viruses).
• Transmission: Germs are injected via mosquito saliva when they bite to suck blood.
• Control: Spray insecticides to kill adults, eliminate puddles, spray oil on stagnant water to suffocate larvae, and introduce biological controls like Gambusia fish that devour mosquito larvae.

Cockroaches & Rats

• Cockroaches: Breed in manholes/sewers, spoil food and clothes, and may carry viral diseases, potentially including cancer-causing viruses. Best controlled by spraying insecticides.
• Rats: Serious domestic pests that eat food and carry the rat-flea. The rat-flea acts as a parasite carrying plague germs. Controlled using traps and rat poisons (raticides).

Contamination of Water and Water-Borne Diseases

Contamination occurs when disease-causing germs enter drinking water. Sources of contamination include leaking sewage, open defecation/urination near water bodies, and animal waste runoff.

Industrial & Agricultural Water Pollutants

• Industrial Mercury: Causes abnormalities in the nervous system.
• Tannery Wastes: May contain anthrax-causing bacilli.
• Pesticides (like DDT): The most serious pollutants; cause hormonal imbalances and lead to cancer.
• Fluorides: Cause tooth, bone, and muscular disorders, and can be fatal in high concentrations.

Three Common Water-Borne Diseases

• 1. Cholera:
  Infection of the intestinal tract by the bacterium Vibrio cholerae.
  Symptoms: Severe diarrhoea, vomiting, dehydration, and lack of urination (leading to fatal accumulation of urea in the blood).
  Transmission: Contaminated water, dust, flies, or dirty hands of food handlers.
• 2. Dysentery:
  Occurs in two forms:
  • Bacillary dysentery: Caused by the bacterium Shigella. Common in children. Symptoms include loose motions, intestinal pain, and mild fever. Treated with antibiotics.
  • Amoebic dysentery: Caused by the protozoan Entamoeba histolytica. Enters via contaminated water/food, feeds on red blood cells in the large intestine, and forms cysts that pass through faeces to infect others.
• 3. Hepatitis:
  Viral infection causing inflammation of the liver. Hepatitis A is transmitted via contaminated water (while B and C pass through blood/body fluids).
  Symptoms: Body ache, yellowish eyes, deep yellow urine (due to bile pigments), and an enlarged liver.
  Prevention: Hepatitis vaccine, maintaining proper hygiene, and avoiding fat-rich foods.